Hello, On Tue, Feb 06, 2018 at 09:50:02PM +0800, Du, Changbin wrote: > Hello all, > I am using perf sched tool to analyzer sched data on my machine. But it seems > that > 'perf sched latency' report incorrect 'Switches'. What I did is as below. > > First, record... > $ sudo perf sched record time pi 2000000 > /dev/null > > Then check statistics. It says 'pi' only sched-in 1 time. > $ sudo ./perf sched latency | grep pi > compiz:4054 | 6.389 ms | 30 | avg: 0.023 ms | max: > 0.122 ms | max at: 94546.021080 s > pi:4059 | 2083.241 ms | 1 | avg: 0.007 ms | max: > 0.007 ms | max at: 94545.201435 s > > But the sched event show 'pi' has been sched-in 7 times. > $ sudo ./perf sched script | grep pi: > pi 4059 [001] 94545.820858: sched:sched_switch: pi:4059 > [120] S ==> kworker/1:1:32237 [120] > kworker/1:1 32237 [001] 94545.820868: sched:sched_switch: > kworker/1:1:32237 [120] R ==> pi:4059 [120] > pi 4059 [001] 94545.885412: sched:sched_switch: pi:4059 > [120] S ==> kworker/1:1H:320 [100] > kworker/1:1H 320 [001] 94545.885419: sched:sched_switch: > kworker/1:1H:320 [100] R ==> pi:4059 [120] > pi 4059 [001] 94545.907869: sched:sched_switch: pi:4059 > [120] S ==> kworker/1:1H:320 [100] > kworker/1:1H 320 [001] 94545.907875: sched:sched_switch: > kworker/1:1H:320 [100] R ==> pi:4059 [120] > pi 4059 [001] 94545.908104: sched:sched_switch: pi:4059 > [120] S ==> kworker/1:1H:320 [100] > kworker/1:1H 320 [001] 94545.908108: sched:sched_switch: > kworker/1:1H:320 [100] R ==> pi:4059 [120] > pi 4059 [001] 94545.916135: sched:sched_switch: pi:4059 > [120] S ==> kworker/1:1H:320 [100] > kworker/1:1H 320 [001] 94545.916154: sched:sched_switch: > kworker/1:1H:320 [100] R ==> pi:4059 [120] > pi 4059 [001] 94546.812856: sched:sched_switch: pi:4059 > [120] S ==> kworker/1:1:32237 [120] > kworker/1:1 32237 [001] 94546.813148: sched:sched_switch: > kworker/1:1:32237 [120] R ==> pi:4059 [120] > pi 4059 [001] 94546.885227: sched:sched_switch: pi:4059 > [120] S ==> i915/signal:1:207 [98] > i915/signal:1 207 [001] 94546.885232: sched:sched_switch: > i915/signal:1:207 [98] D ==> pi:4059 [120] > pi 4059 [001] 94547.285049: sched:sched_switch: pi:4059 > [120] x ==> swapper/1:0 [120] > > Does anyone know why? Thank you! :)
It seems your data doesn't have wakeup event which is required by the 'perf sched latency'. Thanks, Namhyung > > -- > Thanks, > Changbin Du > -- > To unsubscribe from this list: send the line "unsubscribe linux-perf-users" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
