Messages in this thread | | | Subject | Re: [PATCH] sched/fair: change where we report sched stats | From | Mike Galbraith <> | Date | Thu, 11 Dec 2014 04:34:16 +0100 |
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On Wed, 2014-12-10 at 16:48 -0500, Josef Bacik wrote: > On 12/10/2014 01:23 AM, Mike Galbraith wrote: > > On Tue, 2014-12-09 at 13:21 -0500, Josef Bacik wrote: > > > >> This patch moves stat stuff to after the schedule, right as we are waking up, > > > > But sleep/block ends when the task is awakened/enqueued, not when it > > gets the CPU. You're adding scheduling latency, breaking accounting. > > > > Yes I'm aware of that. I don't care if the delay time is slightly > higher than normal, I care about knowing exactly why we were sleeping to > begin with. I suppose I could leave the accounting part where it is and > then just fire the tracepoint when it's put on the CPU so we get the > best of both worlds, but honestly I don't feel like adding the extra > scheduling latency into the accounting is that big of a deal. Thanks,
I think sleep/iowait should remain what they are, sleep/iowait end at wakeup. I don't think waker trace is useless either for that matter. Who/when ends a sleep period is just as much a part of the picture as what triggered that sleep. Waker scheduling latency, thumb twiddling etc. extend sleep.
Shrug, maintainer call. I don't recall ever having any difficulty determining why a task went to sleep, so don't get it.
-Mike
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