{"id":3323,"date":"2025-03-27T10:54:17","date_gmt":"2025-03-27T14:54:17","guid":{"rendered":"https:\/\/blogs.mathworks.com\/matlab\/?p=3323"},"modified":"2025-04-03T09:31:10","modified_gmt":"2025-04-03T13:31:10","slug":"parallel-computing-in-matlab-have-you-tried-threadpools-yet","status":"publish","type":"post","link":"https:\/\/blogs.mathworks.com\/matlab\/2025\/03\/27\/parallel-computing-in-matlab-have-you-tried-threadpools-yet\/","title":{"rendered":"Parallel computing in MATLAB: Have you tried ThreadPools yet?"},"content":{"rendered":"<div class = rtcContent><h2  style = 'margin: 20px 10px 5px 4px; padding: 0px; line-height: 25px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 20px; font-weight: 700; text-align: left; '><span>Give ThreadPool a try<\/span><\/h2><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>If you have some parallel MATLAB code and want to try something that <\/span><span style=' font-weight: bold;'>may<\/span><span> make it go faster then I suggest opening your Parallel pool as follows before running your code.<\/span><\/div><div style=\"background-color: #F5F5F5; margin: 10px 15px 10px 0; display: inline-block\"><div class=\"inlineWrapper\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 4px; padding: 6px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >parpool(<\/span><span style=\"color: #a709f5;\">\"Threads\"<\/span><span >)<\/span><\/span><\/div><\/div><\/div><div  style = 'margin: 10px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>The result will probably be one of the following:<\/span><\/div><ul  style = 'margin: 10px 0px 20px; padding-left: 0px; font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-size: 14px; '><li  style = 'margin-left: 56px; line-height: 21px; min-height: 0px; text-align: left; white-space: pre-wrap; '><span>Your code goes faster than it did before<\/span><\/li><li  style = 'margin-left: 56px; line-height: 21px; min-height: 0px; text-align: left; white-space: pre-wrap; '><span>It's pretty much the same speed as it was before<\/span><\/li><li  style = 'margin-left: 56px; line-height: 21px; min-height: 0px; text-align: left; white-space: pre-wrap; '><span>You get an error message<\/span><\/li><\/ul><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>Whatever the result, you may be wondering what's happening here. That's what this post is all about. <\/span><\/div><h2  style = 'margin: 20px 10px 5px 4px; padding: 0px; line-height: 25px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 20px; font-weight: 700; text-align: left; '><span>The default parallel pool in MATLAB is a ProcessPool<\/span><\/h2><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>Before you start using parallel constructs such as <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parfor.html\"><span style=' font-family: monospace;'>parfor<\/span><\/a><span> and <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parallel.pool.parfeval.html\"><span style=' font-family: monospace;'>parfeval<\/span><\/a><span> from Parallel Computing Toolbox, you need to create a pool of workers and one way of doing this is to use the <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parpool.html\"><span style=' font-family: monospace;'>parpool<\/span><\/a><span> function.<\/span><\/div><div style=\"background-color: #F5F5F5; margin: 10px 15px 10px 0; display: inline-block\"><div class=\"inlineWrapper outputs\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 4px 4px 0px 0px; padding: 6px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >defaultPool = parpool() <\/span><span style=\"color: #008013;\">% This opens a parallel pool using the default profile<\/span><\/span><\/div><div  style = 'color: rgb(33, 33, 33); padding: 10px 0px 6px 17px; background: rgb(255, 255, 255) none repeat scroll 0% 0% \/ auto padding-box border-box; font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; overflow-x: hidden; line-height: 17.234px; '><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsTextElement\" uid=\"526B2271\" prevent-scroll=\"true\" data-testid=\"output_0\" tabindex=\"-1\" style=\"width: 1145px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\" textElement eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"253\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"text output \" style=\"max-height: 264px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">Starting parallel pool (parpool) using the 'Processes' profile ...\r\nConnected to parallel pool with 8 workers.\r\n\r\ndefaultPool = \r\n\r\n ProcessPool with properties: \r\n\r\n            Connected: true\r\n           NumWorkers: 8\r\n                 Busy: false\r\n              Cluster: Processes (Local Cluster)\r\n        AttachedFiles: {}\r\n    AutoAddClientPath: true\r\n            FileStore: [1x1 parallel.FileStore]\r\n           ValueStore: [1x1 parallel.ValueStore]\r\n          IdleTimeout: 30 minutes (30 minutes remaining)\r\n          SpmdEnabled: true<\/div><\/div><\/div><\/div><\/div><div  style = 'margin: 10px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>Out of the box, the default type of parallel pool in MATLAB is a <\/span><span style=' font-family: monospace;'>ProcessPool<\/span><span> and we can see that this is the type of environment that has been created for me above. In a <\/span><span style=' font-family: monospace;'>ProcessPool<\/span><span>, each of the workers have their own <\/span><a href=\"https:\/\/en.wikipedia.org\/wiki\/Process_(computing)\" target=\"_blank\" rel=\"noopener\"><span>process<\/span><\/a><span> and so are completely independent and isolated from each other. They have their own memory, for example, and cannot see each other's memory<\/span><\/div><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>A way of visualizing a <\/span><span style=' font-family: monospace;'>ProcessPool<\/span><span> is shown below<\/span><\/div><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><img class = \"imageNode\" src = \"http:\/\/blogs.mathworks.com\/matlab\/files\/2025\/03\/parpoolTypes_1-1.png\" width = \"451\" height = \"194\" alt = \"process_workers.png\" style = \"vertical-align: baseline; width: 451px; height: 194px;\"><\/img><\/div><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>Back in R2020a, a new type of parallel pool was made available in MATLAB where each worker is a <\/span><a href=\"https:\/\/en.wikipedia.org\/wiki\/Thread_(computing)\" target=\"_blank\" rel=\"noopener\"><span>thread<\/span><\/a><span> instead of a process. Naturally enough, one of these is referred to as a <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parallel.threadpool.html\"><span>ThreadPool<\/span><\/a><span>. Workers in a <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parallel.threadpool.html\"><span>ThreadPool<\/span><\/a><span> are much less isolated, existing in the same process which means, among other things, that they share the same memory<\/span><\/div><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span> <\/span><img class = \"imageNode\" src = \"http:\/\/blogs.mathworks.com\/matlab\/files\/2025\/03\/parpoolTypes_2-1.png\" width = \"451\" height = \"194\" alt = \"thread_workers.png\" style = \"vertical-align: baseline; width: 451px; height: 194px;\"><\/img><span> <\/span><\/div><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>Let's close down our existing <\/span><span style=' font-family: monospace;'>ProcessPool<\/span><span> and open up a <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parallel.threadpool.html\"><span>ThreadPool<\/span><\/a><\/div><div style=\"background-color: #F5F5F5; margin: 10px 15px 10px 0; display: inline-block\"><div class=\"inlineWrapper outputs\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 4px 4px 0px 0px; padding: 6px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >delete(defaultPool) <\/span><span style=\"color: #008013;\">% Close down existing parallel pool<\/span><\/span><\/div><div  style = 'color: rgb(33, 33, 33); padding: 10px 0px 6px 17px; background: rgb(255, 255, 255) none repeat scroll 0% 0% \/ auto padding-box border-box; font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; overflow-x: hidden; line-height: 17.234px; '><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsTextElement\" uid=\"E3F70121\" prevent-scroll=\"true\" data-testid=\"output_1\" tabindex=\"-1\" style=\"width: 1145px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\" textElement eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"17\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"text output \" style=\"max-height: 261px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">Parallel pool using the 'Processes' profile is shutting down.<\/div><\/div><\/div><\/div><div class=\"inlineWrapper outputs\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 0px; padding: 6px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >threadPool = parpool(<\/span><span style=\"color: #a709f5;\">\"Threads\"<\/span><span >)<\/span><\/span><\/div><div  style = 'color: rgb(33, 33, 33); padding: 10px 0px 6px 17px; background: rgb(255, 255, 255) none repeat scroll 0% 0% \/ auto padding-box border-box; font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; overflow-x: hidden; line-height: 17.234px; '><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsTextElement\" uid=\"71990146\" prevent-scroll=\"true\" data-testid=\"output_2\" tabindex=\"-1\" style=\"width: 1145px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\" textElement eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"32\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"text output \" style=\"max-height: 261px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">Starting parallel pool (parpool) using the 'Threads' profile ...\r\nConnected to parallel pool with 8 workers.<\/div><\/div><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsVariableStringElement\" uid=\"C944C2F3\" prevent-scroll=\"true\" data-testid=\"output_3\" tabindex=\"-1\" style=\"width: 1145px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\"textElement eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"108\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"variable output \" style=\"max-height: 261px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><span class=\"variableNameElement\" style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">threadPool = <\/span><\/div><div style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"> ThreadPool with properties: \r\n\r\n           NumWorkers: 8\r\n                 Busy: false\r\n            FileStore: [1x1 parallel.FileStore]\r\n           ValueStore: [1x1 parallel.ValueStore]\r\n<\/div><\/div><\/div><\/div><\/div><\/div><div  style = 'margin: 10px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>From the output of <\/span><span style=' font-family: monospace;'>parpool<\/span><span> alone, you can see that there are differences between <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parallel.threadpool.html\"><span style=' font-family: monospace;'>ThreadPool<\/span><\/a><span>s and <\/span><span style=' font-family: monospace;'>ProcessPool<\/span><span style=' font-family: monospace;'>s<\/span><span>. A <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parallel.threadpool.html\"><span style=' font-family: monospace;'>ThreadPool<\/span><\/a><span> doesn't have an IdleTimeout, for example. Open one up, walk away from MATLAB for as long as you like, and when you return the <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parallel.threadpool.html\"><span style=' font-family: monospace;'>ThreadPool<\/span><\/a><span> will still be open. A <\/span><span style=' font-family: monospace;'>ProcessPool<\/span><span>, on the other hand, will close down if you do nothing with it for 30 minutes.<\/span><\/div><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>Let's close down our <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parallel.threadpool.html\"><span>ThreadPool<\/span><\/a><span> and look at some of the other differences between these pool types. <\/span><\/div><div style=\"background-color: #F5F5F5; margin: 10px 15px 10px 0; display: inline-block\"><div class=\"inlineWrapper outputs\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 4px 4px 0px 0px; padding: 6px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >delete(threadPool) <\/span><span style=\"color: #008013;\">% Close down the parallel pool <\/span><\/span><\/div><div  style = 'color: rgb(33, 33, 33); padding: 10px 0px 6px 17px; background: rgb(255, 255, 255) none repeat scroll 0% 0% \/ auto padding-box border-box; font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; overflow-x: hidden; line-height: 17.234px; '><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsTextElement\" uid=\"AB679A88\" prevent-scroll=\"true\" data-testid=\"output_4\" tabindex=\"-1\" style=\"width: 1145px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\" textElement eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"17\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"text output \" style=\"max-height: 261px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">Parallel pool using the 'Threads' profile is shutting down.<\/div><\/div><\/div><\/div><\/div><h2  style = 'margin: 3px 10px 5px 4px; padding: 0px; line-height: 25px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 20px; font-weight: 700; text-align: left; '><span>ThreadPools start up faster than ProcessPools<\/span><\/h2><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>Threads are more lightweight than processes and one consequence of this is that it is quicker to start a <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parallel.threadpool.html\"><span>ThreadPool<\/span><\/a><span> than a <\/span><span style=' font-family: monospace;'>ProcessPool<\/span><span>.<\/span><\/div><div style=\"background-color: #F5F5F5; margin: 10px 15px 10px 0; display: inline-block\"><div class=\"inlineWrapper\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 0px none rgb(33, 33, 33); border-radius: 4px 4px 0px 0px; padding: 6px 45px 0px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >tic<\/span><\/span><\/div><\/div><div class=\"inlineWrapper outputs\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 0px none rgb(33, 33, 33); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 0px; padding: 0px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >processPool = parpool(<\/span><span style=\"color: #a709f5;\">\"Processes\"<\/span><span >)<\/span><\/span><\/div><div  style = 'color: rgb(33, 33, 33); padding: 10px 0px 6px 17px; background: rgb(255, 255, 255) none repeat scroll 0% 0% \/ auto padding-box border-box; font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; overflow-x: hidden; line-height: 17.234px; '><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsTextElement\" uid=\"80A48DDE\" prevent-scroll=\"true\" data-testid=\"output_5\" tabindex=\"-1\" style=\"width: 1145px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\" textElement eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"253\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"text output \" style=\"max-height: 264px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">Starting parallel pool (parpool) using the 'Processes' profile ...\r\nConnected to parallel pool with 8 workers.\r\n\r\nprocessPool = \r\n\r\n ProcessPool with properties: \r\n\r\n            Connected: true\r\n           NumWorkers: 8\r\n                 Busy: false\r\n              Cluster: Processes (Local Cluster)\r\n        AttachedFiles: {}\r\n    AutoAddClientPath: true\r\n            FileStore: [1x1 parallel.FileStore]\r\n           ValueStore: [1x1 parallel.ValueStore]\r\n          IdleTimeout: 30 minutes (30 minutes remaining)\r\n          SpmdEnabled: true<\/div><\/div><\/div><\/div><div class=\"inlineWrapper outputs\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 0px; padding: 6px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >processTime = toc<\/span><\/span><\/div><div  style = 'color: rgb(33, 33, 33); padding: 10px 0px 6px 17px; background: rgb(255, 255, 255) none repeat scroll 0% 0% \/ auto padding-box border-box; font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; overflow-x: hidden; line-height: 17.234px; '><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsVariableStringElement\" uid=\"5454713D\" prevent-scroll=\"true\" data-testid=\"output_6\" tabindex=\"-1\" style=\"width: 1145px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\"textElement eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"20\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"variable output \" style=\"max-height: 261px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><span class=\"variableNameElement\" style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">processTime = <\/span>28.7807<\/div><\/div><\/div><\/div><\/div><div class=\"inlineWrapper outputs\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 0px; padding: 6px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >delete(processPool)<\/span><\/span><\/div><div  style = 'color: rgb(33, 33, 33); padding: 10px 0px 6px 17px; background: rgb(255, 255, 255) none repeat scroll 0% 0% \/ auto padding-box border-box; font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; overflow-x: hidden; line-height: 17.234px; '><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsTextElement\" uid=\"531687D6\" prevent-scroll=\"true\" data-testid=\"output_7\" tabindex=\"-1\" style=\"width: 1145px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\" textElement eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"17\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"text output \" style=\"max-height: 261px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">Parallel pool using the 'Processes' profile is shutting down.<\/div><\/div><\/div><\/div><\/div><div  style = 'margin: 10px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>You may wonder why I am always deleting pools before moving on. This is because creating concurrent parallel pools in the same MATLAB session is not supported. Let's now time how long it takes to create a ThreadPool<\/span><\/div><div style=\"background-color: #F5F5F5; margin: 10px 15px 10px 0; display: inline-block\"><div class=\"inlineWrapper\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 0px none rgb(33, 33, 33); border-radius: 4px 4px 0px 0px; padding: 6px 45px 0px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >tic<\/span><\/span><\/div><\/div><div class=\"inlineWrapper outputs\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 0px none rgb(33, 33, 33); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 0px; padding: 0px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >threadPool = parpool(<\/span><span style=\"color: #a709f5;\">\"Threads\"<\/span><span >)<\/span><\/span><\/div><div  style = 'color: rgb(33, 33, 33); padding: 10px 0px 6px 17px; background: rgb(255, 255, 255) none repeat scroll 0% 0% \/ auto padding-box border-box; font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; overflow-x: hidden; line-height: 17.234px; '><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsTextElement\" uid=\"B8D0D3C3\" prevent-scroll=\"true\" data-testid=\"output_8\" tabindex=\"-1\" style=\"width: 1145px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\" textElement eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"32\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"text output \" style=\"max-height: 261px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">Starting parallel pool (parpool) using the 'Threads' profile ...\r\nConnected to parallel pool with 8 workers.<\/div><\/div><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsVariableStringElement\" uid=\"D7F77DC7\" prevent-scroll=\"true\" data-testid=\"output_9\" tabindex=\"-1\" style=\"width: 1145px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\"textElement eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"108\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"variable output \" style=\"max-height: 261px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><span class=\"variableNameElement\" style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">processPool = <\/span><\/div><div style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"> ThreadPool with properties: \r\n\r\n           NumWorkers: 8\r\n                 Busy: false\r\n            FileStore: [1x1 parallel.FileStore]\r\n           ValueStore: [1x1 parallel.ValueStore]\r\n<\/div><\/div><\/div><\/div><\/div><div class=\"inlineWrapper outputs\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 0px; padding: 6px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >threadTime = toc<\/span><\/span><\/div><div  style = 'color: rgb(33, 33, 33); padding: 10px 0px 6px 17px; background: rgb(255, 255, 255) none repeat scroll 0% 0% \/ auto padding-box border-box; font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; overflow-x: hidden; line-height: 17.234px; '><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsVariableStringElement\" uid=\"21CC1D5E\" prevent-scroll=\"true\" data-testid=\"output_10\" tabindex=\"-1\" style=\"width: 1145px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\"textElement eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"20\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"variable output \" style=\"max-height: 261px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><span class=\"variableNameElement\" style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">threadTime = <\/span>0.0992<\/div><\/div><\/div><\/div><\/div><div class=\"inlineWrapper outputs\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 0px; padding: 6px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >delete(threadPool)<\/span><\/span><\/div><div  style = 'color: rgb(33, 33, 33); padding: 10px 0px 6px 17px; background: rgb(255, 255, 255) none repeat scroll 0% 0% \/ auto padding-box border-box; font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; overflow-x: hidden; line-height: 17.234px; '><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsTextElement\" uid=\"E296475C\" prevent-scroll=\"true\" data-testid=\"output_11\" tabindex=\"-1\" style=\"width: 1145px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\" textElement eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"17\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"text output \" style=\"max-height: 261px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">Parallel pool using the 'Threads' profile is shutting down.<\/div><\/div><\/div><\/div><\/div><div  style = 'margin: 10px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>Let's plot the results.<\/span><\/div><div style=\"background-color: #F5F5F5; margin: 10px 15px 10px 0; display: inline-block\"><div class=\"inlineWrapper\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 0px none rgb(33, 33, 33); border-radius: 4px 4px 0px 0px; padding: 6px 45px 0px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >barh([processTime,threadTime])<\/span><\/span><\/div><\/div><div class=\"inlineWrapper\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 0px none rgb(33, 33, 33); border-bottom: 0px none rgb(33, 33, 33); border-radius: 0px; padding: 0px 45px 0px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >yticklabels([<\/span><span style=\"color: #a709f5;\">\"Processes\"<\/span><span >,<\/span><span style=\"color: #a709f5;\">\"Threads\"<\/span><span >]);<\/span><\/span><\/div><\/div><div class=\"inlineWrapper outputs\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 0px none rgb(33, 33, 33); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 0px; padding: 0px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >xlabel(<\/span><span style=\"color: #a709f5;\">'Pool startup time (s)'<\/span><span >)<\/span><\/span><\/div><div  style = 'color: rgb(33, 33, 33); padding: 10px 0px 6px 17px; background: rgb(255, 255, 255) none repeat scroll 0% 0% \/ auto padding-box border-box; font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; overflow-x: hidden; line-height: 17.234px; '><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsFigure\" uid=\"97CE1613\" prevent-scroll=\"true\" data-testid=\"output_12\" tabindex=\"-1\" style=\"width: 1145px;\"><div class=\"figureElement eoOutputContent\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"figure output \"><img decoding=\"async\" class=\"figureImage figureContainingNode\" src=\"http:\/\/blogs.mathworks.com\/matlab\/files\/2025\/03\/parpoolTypes_3-1.png\" style=\"width: 560px;\"><\/div><div class=\"outputLayer selectedOutputDecorationLayer doNotExport\" aria-hidden=\"true\"><\/div><div class=\"outputLayer activeOutputDecorationLayer doNotExport\" aria-hidden=\"true\"><\/div><div class=\"outputLayer scrollableOutputDecorationLayer doNotExport\" aria-hidden=\"true\"><\/div><div class=\"outputLayer navigationFocusLayer doNotExport\" aria-hidden=\"false\" tabindex=\"-1\" role=\"application\" aria-label=\"figure output \"><\/div><\/div><\/div><\/div><div class=\"inlineWrapper outputs\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 0px; padding: 6px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >fprintf(<\/span><span style=\"color: #a709f5;\">\"It is %.2f times faster to create a Threads pool than a Processes pool\\n\"<\/span><span >,processTime\/threadTime)<\/span><\/span><\/div><div  style = 'color: rgb(33, 33, 33); padding: 10px 0px 6px 17px; background: rgb(255, 255, 255) none repeat scroll 0% 0% \/ auto padding-box border-box; font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; overflow-x: hidden; line-height: 17.234px; '><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsTextElement\" uid=\"905E8ED9\" prevent-scroll=\"true\" data-testid=\"output_13\" tabindex=\"-1\" style=\"width: 1145px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\" textElement eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"17\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"text output \" style=\"max-height: 261px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">It is 290.20 times faster to create a Threads pool than a Processes pool<\/div><\/div><\/div><\/div><\/div><div  style = 'margin: 10px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>Your mileage may vary but I am sure that your overall result will be the same as mine: It is significantly faster to create a ThreadPool than a ProcessPool.  <\/span><\/div><h2  style = 'margin: 3px 10px 5px 4px; padding: 0px; line-height: 25px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 20px; font-weight: 700; text-align: left; '><span>Code run on a Threads pool is often faster, primarily because of shared memory<\/span><\/h2><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>All of the workers in a <\/span><span style=' font-family: monospace;'>ProcessPool<\/span><span> have their own, independent piece of memory. If you want a worker to see something from elsewhere, either from the main MATLAB process or from another worker, the data needs to be sent to it. You often don't realize this because convenience functions such as <\/span><span style=' font-family: monospace;'>parfor<\/span><span> do the work for you automatically but you can <\/span><span style=' font-weight: bold;'>see<\/span><span> it with <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parallel.pool.ticbytes.html\"><span style=' font-family: monospace;'>ticBytes<\/span><\/a><span style=' font-family: monospace;'>\/<\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parallel.pool.tocbytes.html\"><span style=' font-family: monospace;'>tocBytes<\/span><\/a><span> which measures memory movement between client and workers.<\/span><\/div><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>Consider this function<\/span><\/div><div style=\"background-color: #F5F5F5; margin: 10px 15px 10px 0; display: inline-block\"><div class=\"inlineWrapper\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 0px none rgb(33, 33, 33); border-radius: 4px 4px 0px 0px; padding: 6px 45px 0px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span style=\"color: #0e00ff;\">function <\/span><span >[t,out] = poolExample(n)<\/span><\/span><\/div><\/div><div class=\"inlineWrapper\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 0px none rgb(33, 33, 33); border-bottom: 0px none rgb(33, 33, 33); border-radius: 0px; padding: 0px 45px 0px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >data = rand(n);<\/span><\/span><\/div><\/div><div class=\"inlineWrapper\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 0px none rgb(33, 33, 33); border-bottom: 0px none rgb(33, 33, 33); border-radius: 0px; padding: 0px 45px 0px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >timer = tic();<\/span><\/span><\/div><\/div><div class=\"inlineWrapper\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 0px none rgb(33, 33, 33); border-bottom: 0px none rgb(33, 33, 33); border-radius: 0px; padding: 0px 45px 0px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span style=\"color: #0e00ff;\">parfor <\/span><span >i = 1:n<\/span><\/span><\/div><\/div><div class=\"inlineWrapper\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 0px none rgb(33, 33, 33); border-bottom: 0px none rgb(33, 33, 33); border-radius: 0px; padding: 0px 45px 0px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >    out(i) = data(i,:) * data(:,i);<\/span><\/span><\/div><\/div><div class=\"inlineWrapper\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 0px none rgb(33, 33, 33); border-bottom: 0px none rgb(33, 33, 33); border-radius: 0px; padding: 0px 45px 0px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span style=\"color: #0e00ff;\">end<\/span><\/span><\/div><\/div><div class=\"inlineWrapper\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 0px none rgb(33, 33, 33); border-bottom: 0px none rgb(33, 33, 33); border-radius: 0px; padding: 0px 45px 0px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >t = toc(timer);<\/span><\/span><\/div><\/div><div class=\"inlineWrapper\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 0px none rgb(33, 33, 33); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 0px 0px 4px 4px; padding: 0px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span style=\"color: #0e00ff;\">end<\/span><\/span><\/div><\/div><\/div><div  style = 'margin: 10px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>We open a <\/span><span style=' font-family: monospace;'>ProcessPool<\/span><\/div><div style=\"background-color: #F5F5F5; margin: 10px 15px 10px 0; display: inline-block\"><div class=\"inlineWrapper outputs\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 4px 4px 0px 0px; padding: 6px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >processPool = parpool(<\/span><span style=\"color: #a709f5;\">\"Processes\"<\/span><span >);<\/span><\/span><\/div><div  style = 'color: rgb(33, 33, 33); padding: 10px 0px 6px 17px; background: rgb(255, 255, 255) none repeat scroll 0% 0% \/ auto padding-box border-box; font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; overflow-x: hidden; line-height: 17.234px; '><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsTextElement\" uid=\"61E293F2\" prevent-scroll=\"true\" data-testid=\"output_14\" tabindex=\"-1\" style=\"width: 1145px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\" textElement eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"32\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"text output \" style=\"max-height: 261px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">Starting parallel pool (parpool) using the 'Processes' profile ...\r\nConnected to parallel pool with 8 workers.<\/div><\/div><\/div><\/div><\/div><div  style = 'margin: 10px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>and run the code<\/span><\/div><div style=\"background-color: #F5F5F5; margin: 10px 15px 10px 0; display: inline-block\"><div class=\"inlineWrapper\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 0px none rgb(33, 33, 33); border-radius: 4px 4px 0px 0px; padding: 6px 45px 0px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >ticBytes(processPool)<\/span><\/span><\/div><\/div><div class=\"inlineWrapper\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 0px none rgb(33, 33, 33); border-bottom: 0px none rgb(33, 33, 33); border-radius: 0px; padding: 0px 45px 0px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >[processPoolTime,result] = poolExample(2000);<\/span><\/span><\/div><\/div><div class=\"inlineWrapper outputs\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 0px none rgb(33, 33, 33); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 0px; padding: 0px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >tocBytes(processPool)<\/span><\/span><\/div><div  style = 'color: rgb(33, 33, 33); padding: 10px 0px 6px 17px; background: rgb(255, 255, 255) none repeat scroll 0% 0% \/ auto padding-box border-box; font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; overflow-x: hidden; line-height: 17.234px; '><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsTextElement\" uid=\"0E8D1BCB\" prevent-scroll=\"true\" data-testid=\"output_15\" tabindex=\"-1\" style=\"width: 1145px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\" textElement eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"179\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"text output \" style=\"max-height: 261px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">             <strong style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">BytesSentToWorkers<\/strong>    <strong style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">BytesReceivedFromWorkers<\/strong>\r\n             <strong style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">__________________<\/strong>    <strong style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">________________________<\/strong>\r\n\r\n    <strong style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">1    <\/strong>         3.201e+07                  4357          \r\n    <strong style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">2    <\/strong>        3.2012e+07                  6318          \r\n    <strong style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">3    <\/strong>        3.2007e+07                  2105          \r\n    <strong style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">4    <\/strong>         3.202e+07                 15634          \r\n    <strong style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">5    <\/strong>        3.2009e+07                  3802          \r\n    <strong style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">6    <\/strong>        3.2007e+07                  2105          \r\n    <strong style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">7    <\/strong>        3.2007e+07                  1625          \r\n    <strong style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">8    <\/strong>        3.2012e+07                  6422          \r\n    <strong style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">Total<\/strong>        2.5608e+08                 42368          <\/div><\/div><\/div><\/div><\/div><div  style = 'margin: 10px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>The time taken to run the function on the <\/span><span style=' font-family: monospace;'>ProcessPool<\/span><span> is<\/span><\/div><div style=\"background-color: #F5F5F5; margin: 10px 15px 10px 0; display: inline-block\"><div class=\"inlineWrapper outputs\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 4px 4px 0px 0px; padding: 6px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >fprintf(<\/span><span style=\"color: #a709f5;\">\"Parallel loop completed on Process pool in %.2f seconds\\n\"<\/span><span >,processPoolTime)<\/span><\/span><\/div><div  style = 'color: rgb(33, 33, 33); padding: 10px 0px 6px 17px; background: rgb(255, 255, 255) none repeat scroll 0% 0% \/ auto padding-box border-box; font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; overflow-x: hidden; line-height: 17.234px; '><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsTextElement\" uid=\"6007B638\" prevent-scroll=\"true\" data-testid=\"output_16\" tabindex=\"-1\" style=\"width: 1145px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\" textElement eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"17\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"text output \" style=\"max-height: 261px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">Parallel loop completed on Process pool in 0.35 seconds<\/div><\/div><\/div><\/div><div class=\"inlineWrapper outputs\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 0px; padding: 6px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >delete(processPool)<\/span><\/span><\/div><div  style = 'color: rgb(33, 33, 33); padding: 10px 0px 6px 17px; background: rgb(255, 255, 255) none repeat scroll 0% 0% \/ auto padding-box border-box; font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; overflow-x: hidden; line-height: 17.234px; '><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsTextElement\" uid=\"9AAF69A5\" prevent-scroll=\"true\" data-testid=\"output_17\" tabindex=\"-1\" style=\"width: 1145px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\" textElement eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"17\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"text output \" style=\"max-height: 261px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">Parallel pool using the 'Processes' profile is shutting down.<\/div><\/div><\/div><\/div><\/div><div  style = 'margin: 10px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>In this example, the entire array <\/span><span style=' font-family: monospace;'>data<\/span><span> is sent from the client MATLAB process <\/span><span style=' font-weight: bold;'>to every worker<\/span><span>. The array is of size <\/span><span style=' font-family: monospace;'>2000*2000*8 = 3.2e+07<\/span><span> and I have 8 workers so there is <\/span><span style=' font-family: monospace;'>2.56e+08<\/span><span> bytes, almost quarter of a gigabyte, of data movement. Such data movement takes time. The tragedy is that each of these copies of <\/span><span style=' font-family: monospace;'>data<\/span><span> is identical and are never changed in the body of the loop so all of that time is due to wasted effort. <\/span><\/div><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>With a Threads pool, memory is shared between workers which vastly reduces the movement of data between them. As such, parallel code run on a Threads pool is often faster than that on a process pool since you don't need to pay data movement costs.  <\/span><\/div><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>I can show you that the code is indeed faster on a <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parallel.threadpool.html\"><span>ThreadPool<\/span><\/a><span>:<\/span><\/div><div style=\"background-color: #F5F5F5; margin: 10px 15px 10px 0; display: inline-block\"><div class=\"inlineWrapper outputs\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 4px 4px 0px 0px; padding: 6px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >threadsPool = parpool(<\/span><span style=\"color: #a709f5;\">\"Threads\"<\/span><span >);<\/span><\/span><\/div><div  style = 'color: rgb(33, 33, 33); padding: 10px 0px 6px 17px; background: rgb(255, 255, 255) none repeat scroll 0% 0% \/ auto padding-box border-box; font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; overflow-x: hidden; line-height: 17.234px; '><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsTextElement\" uid=\"995F58E6\" prevent-scroll=\"true\" data-testid=\"output_18\" tabindex=\"-1\" style=\"width: 1145px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\" textElement eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"32\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"text output \" style=\"max-height: 261px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">Starting parallel pool (parpool) using the 'Threads' profile ...\r\nConnected to parallel pool with 8 workers.<\/div><\/div><\/div><\/div><div class=\"inlineWrapper\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 0px none rgb(33, 33, 33); border-radius: 0px; padding: 6px 45px 0px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >[threadPoolTime,result] = poolExample(2000);<\/span><\/span><\/div><\/div><div class=\"inlineWrapper outputs\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 0px none rgb(33, 33, 33); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 0px; padding: 0px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >fprintf(<\/span><span style=\"color: #a709f5;\">\"Parallel loop completed on Threads pool in %.2f seconds\\n\"<\/span><span >,threadPoolTime);<\/span><\/span><\/div><div  style = 'color: rgb(33, 33, 33); padding: 10px 0px 6px 17px; background: rgb(255, 255, 255) none repeat scroll 0% 0% \/ auto padding-box border-box; font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; overflow-x: hidden; line-height: 17.234px; '><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsTextElement\" uid=\"CDBFC48F\" prevent-scroll=\"true\" data-testid=\"output_19\" tabindex=\"-1\" style=\"width: 1145px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\" textElement eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"17\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"text output \" style=\"max-height: 261px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">Parallel loop completed on Threads pool in 0.03 seconds<\/div><\/div><\/div><\/div><div class=\"inlineWrapper outputs\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 0px; padding: 6px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >fprintf(<\/span><span style=\"color: #a709f5;\">\"The loop ran %.2fx faster on a Threads pool\\n\"<\/span><span >,processPoolTime\/threadPoolTime);<\/span><\/span><\/div><div  style = 'color: rgb(33, 33, 33); padding: 10px 0px 6px 17px; background: rgb(255, 255, 255) none repeat scroll 0% 0% \/ auto padding-box border-box; font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; overflow-x: hidden; line-height: 17.234px; '><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsTextElement\" uid=\"96EADC34\" prevent-scroll=\"true\" data-testid=\"output_20\" tabindex=\"-1\" style=\"width: 1145px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\" textElement eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"17\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"text output \" style=\"max-height: 261px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">The loop ran 10.71x faster on a Threads pool<\/div><\/div><\/div><\/div><\/div><div  style = 'margin: 10px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>and I can tell you that the <\/span><span style=' font-weight: bold;'>primary<\/span><span> reason why this code is faster on a is because of shared memory but what I can't do is demonstrate this because <\/span><span style=' font-family: monospace;'>ticBytes\/tocBytes<\/span><span> don't work in a <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parallel.threadpool.html\"><span>ThreadPool<\/span><\/a><span>: <\/span><\/div><div style=\"background-color: #F5F5F5; margin: 10px 15px 10px 0; display: inline-block\"><div class=\"inlineWrapper\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 1px solid rgb(217, 217, 217); border-bottom: 0px none rgb(33, 33, 33); border-radius: 4px 4px 0px 0px; padding: 6px 45px 0px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >ticBytes(threadsPool)<\/span><\/span><\/div><\/div><div class=\"inlineWrapper\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 0px none rgb(33, 33, 33); border-bottom: 0px none rgb(33, 33, 33); border-radius: 0px; padding: 0px 45px 0px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >[threadPoolTime,result] = poolExample(2000);<\/span><\/span><\/div><\/div><div class=\"inlineWrapper outputs\"><div  style = 'border-left: 1px solid rgb(217, 217, 217); border-right: 1px solid rgb(217, 217, 217); border-top: 0px none rgb(33, 33, 33); border-bottom: 1px solid rgb(217, 217, 217); border-radius: 0px; padding: 0px 45px 4px 13px; line-height: 18.004px; min-height: 0px; white-space: nowrap; color: rgb(33, 33, 33); font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace, Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; '><span style=\"white-space: pre\"><span >tocBytes(threadsPool)<\/span><\/span><\/div><div  style = 'color: rgb(33, 33, 33); padding: 10px 0px 6px 17px; background: rgb(255, 255, 255) none repeat scroll 0% 0% \/ auto padding-box border-box; font-family: Menlo, Monaco, Consolas, \"Courier New\", monospace; font-size: 14px; overflow-x: hidden; line-height: 17.234px; '><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsWarningElement\" uid=\"A1F6FC5B\" prevent-scroll=\"true\" data-testid=\"output_21\" tabindex=\"-1\" style=\"width: 1145px; white-space: normal; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\"diagnosticMessage-wrapper diagnosticMessage-warningType eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"19\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"warning output \" style=\"max-height: 261px; white-space: normal; font-style: normal; color: rgb(179, 98, 5); font-size: 12px;\"><div class=\"diagnosticMessage-messagePart\" style=\"white-space: pre-wrap; font-style: normal; color: rgb(179, 98, 5); font-size: 12px;\">Warning: Thread-based pools do not support measuring bytes sent to or received from workers.<\/div><div class=\"diagnosticMessage-stackPart\" style=\"white-space: pre; font-style: normal; color: rgb(179, 98, 5); font-size: 12px;\"><\/div><\/div><\/div><div class=\"inlineElement eoOutputWrapper disableDefaultGestureHandling embeddedOutputsTextElement\" uid=\"F8831724\" prevent-scroll=\"true\" data-testid=\"output_22\" tabindex=\"-1\" style=\"width: 1145px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\"><div class=\" textElement eoOutputContent\" tabindex=\"-1\" data-previous-available-width=\"1108\" data-previous-scroll-height=\"61\" data-hashorizontaloverflow=\"false\" role=\"article\" aria-roledescription=\"Use Browse Mode to explore \" aria-description=\"text output \" style=\"max-height: 261px; white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">             <strong style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">BytesSentToWorkers<\/strong>    <strong style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">BytesReceivedFromWorkers<\/strong>\r\n             <strong style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">__________________<\/strong>    <strong style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">________________________<\/strong>\r\n\r\n    <strong style=\"white-space: pre; font-style: normal; color: rgb(33, 33, 33); font-size: 12px;\">Total<\/strong>           NaN                      NaN           <\/div><\/div><\/div><\/div><\/div><div  style = 'margin: 10px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>which leads us to our next point.<\/span><\/div><h2  style = 'margin: 20px 10px 5px 4px; padding: 0px; line-height: 25px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 20px; font-weight: 700; text-align: left; '><span>There are some MATLAB features that don't work on ThreadPools, which is why they are not the default yet<\/span><\/h2><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>I have many conversations with MATLAB users that go like this:<\/span><\/div><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span style=' font-weight: bold;'>Them: <\/span><span>\"Can you help me make my parallel MATLAB code go faster please\"?<\/span><\/div><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span style=' font-weight: bold;'>Me<\/span><span>: \"Sure. I'm a bit busy right now but in the meantime just try a <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parallel.threadpool.html\"><span>ThreadPool<\/span><\/a><span>\"<\/span><\/div><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span style=' font-weight: bold;'>Them:<\/span><span> \"Wow! It went faster. Why isn't this the default?\"<\/span><\/div><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>and the reason why it isn't the default is that a <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parallel.threadpool.html\"><span>ThreadPool<\/span><\/a><span> doesn't yet cover all of the MATLAB language. This is something that we are actively working on of course and if you take a look at the <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/release-notes.html\"><span>release notes for parallel computing<\/span><\/a><span> you'll see that, at the time of writing, most recent releases include some additional work related to <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parallel.threadpool.html\"><span>ThreadPool<\/span><\/a><span>. <\/span><\/div><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>Out of the box, we've decided that the default should be the pool type that supports the most stuff. If you disagree with this thinking then you can <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parallel-preferences.html\"><span>change the default pool type for your own MATLAB via Parallel Preferences<\/span><\/a><span>.<\/span><\/div><h2  style = 'margin: 20px 10px 5px 4px; padding: 0px; line-height: 25px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 20px; font-weight: 700; text-align: left; '><span>A ThreadPool can't scale to more than one compute node<\/span><\/h2><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>It's tempting to consider <\/span><span style=' font-family: monospace;'>ProcessPool<\/span><span> as legacy. Sooner or later, you think to yourself, all of the MATLAB language will be supported by <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parallel.threadpool.html\"><span>ThreadPool<\/span><\/a><span>, MathWorks will make it the default and we'll never look back. <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parallel.threadpool.html\"><span style=' font-family: monospace;'>ThreadPool<\/span><\/a><span> for ever! <\/span><\/div><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>However, there will always be one very important use case for <\/span><span style=' font-family: monospace;'>ProcessPool<\/span><span> and that is on multi-node High Performance Computing (HPC) systems. Since compute nodes on a HPC cluster are independent but connected machines with their own memory etc, you can only use a  <\/span><span style=' font-family: monospace;'>ProcessPool<\/span><span style=' font-family: monospace;'> <\/span><span>if you want to scale your code to run on multiple nodes. You can't use a shared memory <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parallel.threadpool.html\"><span style=' font-family: monospace;'>ThreadPool<\/span><\/a><span> because there is no shared memory between nodes. <\/span><\/div><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><span>Loosely speaking I think of a <\/span><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/parallel.threadpool.html\"><span style=' font-family: monospace;'>ThreadPool<\/span><\/a><span> as being 'OpenMP-like' and <\/span><span style=' font-family: monospace;'>ProcessPool<\/span><span> as being 'MPI-like'. If that statement makes no sense at all to you, don't worry about it, just know that the key to scaling MATLAB code to multiple nodes and thousands of CPU cores is <\/span><span style=' font-family: monospace;'>ProcessPool<\/span><span style=' font-family: monospace;'>s.<\/span><span> <\/span><\/div><h2  style = 'margin: 20px 10px 5px 4px; padding: 0px; line-height: 25px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 20px; font-weight: 700; text-align: left; '><span>Resources and further reading<\/span><\/h2><ul  style = 'margin: 10px 0px 20px; padding-left: 0px; font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-size: 14px; '><li  style = 'margin-left: 56px; line-height: 21px; min-height: 0px; text-align: left; white-space: pre-wrap; '><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/run-code-on-parallel-pools.html\"><span>Run Code on Parallel Pools<\/span><\/a><\/li><li  style = 'margin-left: 56px; line-height: 21px; min-height: 0px; text-align: left; white-space: pre-wrap; '><a href = \"https:\/\/uk.mathworks.com\/help\/parallel-computing\/choose-between-thread-based-and-process-based-environments.html\"><span>Choose between Thread-Based and Process-Based Environments<\/span><\/a><\/li><\/ul><div  style = 'margin: 2px 10px 9px 4px; padding: 0px; line-height: 21px; min-height: 0px; white-space: pre-wrap; color: rgb(33, 33, 33); font-family: Helvetica, Arial, sans-serif, Helvetica, Arial, sans-serif; font-style: normal; font-size: 14px; font-weight: 400; text-align: left; '><\/div>\r\n<\/div><script type=\"text\/javascript\">var css = '.eoOutputWrapper { width: calc(90vw - 10px) !important; } \/* Styling that is common to warnings and errors is in diagnosticOutput.css *\/.embeddedOutputsErrorElement {    min-height: 18px;    max-height: 550px;} .embeddedOutputsErrorElement .diagnosticMessage-errorType {    overflow: auto;} .embeddedOutputsErrorElement.activeOutput .eoOutputContent {    user-select: text; 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Hence we needa selector for each.*\/.embeddedOutputsTextElement .eoOutputContent::selection,.embeddedOutputsTextElement .eoOutputContent ::selection,.embeddedOutputsVariableStringElement .eoOutputContent ::selection {} .textElement,.rtcDataTipElement .textElement {    padding-top: 2px;} .embeddedOutputsTextElement.inlineElement,.embeddedOutputsVariableStringElement.inlineElement {} .inlineElement .textElement {} .embeddedOutputsTextElement.rightPaneElement,.embeddedOutputsVariableStringElement.rightPaneElement {    min-height: 16px;} .rightPaneElement .textElement {    padding-top: 2px;    padding-left: 9px;}'; var head = document.head || document.getElementsByTagName('head')[0], style = document.createElement('style'); head.appendChild(style); style.type = 'text\/css'; if (style.styleSheet){ style.styleSheet.cssText = css; } else { style.appendChild(document.createTextNode(css)); }<\/script>","protected":false},"excerpt":{"rendered":"<div class=\"overview-image\"><img src=\"https:\/\/blogs.mathworks.com\/matlab\/files\/2025\/03\/parpoolTypes_3-1.png\" class=\"img-responsive attachment-post-thumbnail size-post-thumbnail wp-post-image\" alt=\"\" decoding=\"async\" loading=\"lazy\" \/><\/div><p>Give ThreadPool a tryIf you have some parallel MATLAB code and want to try something that may make it go faster then I suggest opening your Parallel pool as follows before running your... <a class=\"read-more\" href=\"https:\/\/blogs.mathworks.com\/matlab\/2025\/03\/27\/parallel-computing-in-matlab-have-you-tried-threadpools-yet\/\">read more >><\/a><\/p>","protected":false},"author":176,"featured_media":3317,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[68,42,17,14,85],"tags":[],"_links":{"self":[{"href":"https:\/\/blogs.mathworks.com\/matlab\/wp-json\/wp\/v2\/posts\/3323"}],"collection":[{"href":"https:\/\/blogs.mathworks.com\/matlab\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.mathworks.com\/matlab\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.mathworks.com\/matlab\/wp-json\/wp\/v2\/users\/176"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.mathworks.com\/matlab\/wp-json\/wp\/v2\/comments?post=3323"}],"version-history":[{"count":3,"href":"https:\/\/blogs.mathworks.com\/matlab\/wp-json\/wp\/v2\/posts\/3323\/revisions"}],"predecessor-version":[{"id":3332,"href":"https:\/\/blogs.mathworks.com\/matlab\/wp-json\/wp\/v2\/posts\/3323\/revisions\/3332"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.mathworks.com\/matlab\/wp-json\/wp\/v2\/media\/3317"}],"wp:attachment":[{"href":"https:\/\/blogs.mathworks.com\/matlab\/wp-json\/wp\/v2\/media?parent=3323"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.mathworks.com\/matlab\/wp-json\/wp\/v2\/categories?post=3323"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.mathworks.com\/matlab\/wp-json\/wp\/v2\/tags?post=3323"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}