Messages in this thread | | | From | Valentin Schneider <> | Subject | Re: [PATCH v4 17/19] sched: Add migrate_disable() tracepoints | Date | Thu, 29 Oct 2020 17:56:12 +0000 |
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On 29/10/20 17:43, Peter Zijlstra wrote: > On Thu, Oct 29, 2020 at 04:27:26PM +0000, Valentin Schneider wrote: >> Don't you want those directly after the ->migration_disabled write? >> esp. for migrate_enable(), if that preempt_enable() leads to a context >> switch then the disable->enable deltas won't reflect the kernel view. >> >> That delta may indeed include the time it took to run the stopper and >> fix the task's affinity on migrate_enable(), but it could include all >> sorts of other higher-priority tasks. > > I can put them in the preempt_disable() section I suppose, but these > tracers should be looking at task_sched_runtime(), not walltime, and > then the preemption doesn't matter. >
True. I was thinking of how to process it downstream, and the first thing that came to mind was that rd->overutilized flag which we do monitor fairly closely; however that is system-wide while migrate_disable() is task-specific.
> Also, a distinct lack of actual users atm.. :/
If you'd rather ditch this one altogether until someone asks for it, that also works for me.
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