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Filename :
latencytap.txt
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latencytap.stp - Show Reasons and Durations for Processes Sleeping The latencytap.stp script collects data on the intervals processes are deactivated (sleeping). The script categorizes the reasons for the sleeps by analyzing the backtraces and displays a sorted list of the top 20 causes from largest total sum time sleeping to smallest. The output is updated every 30 seconds. The script needs to be compiled with the '--all-modules' option to produce reasons for sleeps caused by modules. Optionally, this script can be used with the '-c' or '-x' options to focus on a specific PID. $ stap latencytap.stp --all-modules -w Reason Count Average(us) Maximum(us) Percent% kernel workqueue thread 109 1232008 14462131 44% Waiting for event (poll) 3 13340013 20020024 13% Waiting for event (poll) 148 200224 200381 9% RCU grace period kernel thread 7 4010912 9997792 9% 5 5615087 9997712 9% jdb2() kernel thread 2 10716824 14449748 7% Application requested delay 2 9999829 9999833 6% jdb2() kernel thread 3 288906 541672 0% RCU grace period kernel thread 8 2542 2994 0% 7 2519 2958 0% Creating block layer request 1 1599 1599 0% Submitting block IO 15 103 118 0% jdb2() kernel thread 3 333 395 0% Waiting for event (epoll) 1 342 342 0% Creating block layer request 1 271 271 0%