From: "Du, Changbin" <changbin.du@intel.com>
To: jolsa@redhat.com, peterz@infradead.org,
linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org
Cc: changbin.du@intel.com
Subject: A problem about 'perf sched latency'
Date: Tue, 6 Feb 2018 21:50:02 +0800 [thread overview]
Message-ID: <20180206135002.sn32vfqgfz326rcb@intel.com> (raw)
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! :)
--
Thanks,
Changbin Du
next reply other threads:[~2018-02-06 13:58 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-06 13:50 Du, Changbin [this message]
2018-02-08 0:57 ` Namhyung Kim
2018-02-08 3:05 ` Du, Changbin
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