Mike Galbraith 55ffb7a6bd perf sched: Add -C option to measure on a specific CPU ... To refresh, trying to sched record only one CPU results in bogus latencies as below. I fixed^Wmade it stop doing the bad thing today, by following task migration events properly. Before: marge:/root/tmp # taskset -c 1 perf sched record -C 0 -- sleep 10 marge:/root/tmp # perf sched lat ----------------------------------------------------------------------------------------- Task | Runtime ms | Switches | Average delay ms | Maximum delay ms | ----------------------------------------------------------------------------------------- Xorg:4943 | 1.290 ms | 1 | avg: 1670.132 ms | max: 1670.132 ms | hald-addon-stor:3569 | 0.091 ms | 3 | avg: 658.609 ms | max: 1975.797 ms | hald-addon-stor:3573 | 0.209 ms | 4 | avg: 499.138 ms | max: 1990.565 ms | audispd:4270 | 0.012 ms | 1 | avg: 0.015 ms | max: 0.015 ms | .... marge:/root/tmp # perf sched trace|grep 'Xorg:4943' swapper-0 [000] 401.184013288: sched_stat_runtime: task: Xorg:4943 runtime: 1233188 [ns], vruntime: 19105169779 [ns] rt2870TimerQHan-4947 [000] 402.854140127: sched_stat_wait: task: Xorg:4943 wait: 580073 [ns] rt2870TimerQHan-4947 [000] 402.854141770: sched_migrate_task: task Xorg:4943 [140] from: 1 to: 0 rt2870TimerQHan-4947 [000] 402.854143854: sched_stat_wait: task: Xorg:4943 wait: 0 [ns] rt2870TimerQHan-4947 [000] 402.854145397: sched_switch: task rt2870TimerQHan:4947 [140] (D) ==> Xorg:4943 [140] Xorg-4943 [000] 402.854193133: sched_stat_runtime: task: Xorg:4943 runtime: 56546 [ns], vruntime: 11766332500 [ns] Xorg-4943 [000] 402.854196842: sched_switch: task Xorg:4943 [140] (S) ==> swapper:0 [140] After: marge:/root/tmp # taskset -c 1 perf sched record -C 0 -- sleep 10 marge:/root/tmp # perf sched lat ----------------------------------------------------------------------------------------- Task | Runtime ms | Switches | Average delay ms | Maximum delay ms | ----------------------------------------------------------------------------------------- amarokapp:11150 | 271.297 ms | 878 | avg: 0.130 ms | max: 1.057 ms | konsole:5965 | 1.370 ms | 12 | avg: 0.092 ms | max: 0.855 ms | Xorg:4943 | 179.980 ms | 1109 | avg: 0.087 ms | max: 1.206 ms | hald-addon-stor:3574 | 0.212 ms | 9 | avg: 0.040 ms | max: 0.169 ms | hald-addon-stor:3570 | 0.223 ms | 9 | avg: 0.037 ms | max: 0.223 ms | klauncher:5864 | 0.550 ms | 8 | avg: 0.032 ms | max: 0.048 ms | The 'Maximum delay ms' results are now sane. Signed-off-by: Mike Galbraith <efault@gmx.de> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>		2009-10-12 09:10:55 +02:00
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perf	perf sched: Add -C option to measure on a specific CPU	2009-10-12 09:10:55 +02:00