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SubjectRe: [PATCH 3/3] context_tracking,x86: remove extraneous irq disable & enable from context tracking on syscall entry

* Ingo Molnar <mingo@kernel.org> wrote:

> > 2. To suppress the timing tick, we need to get some timing for,
> > um, the scheduler? I wasn't really sure about this one.
>
> So we have variable timeslice timers for the scheduler implemented,
> they are off by default but they worked last someone tried them. See
> the 'HRTICK' scheduler feature.
>
> And for SCHED_FIFO that timeout can be 'never' - i.e. essentially
> stopping the scheduler tick. (within reason.)

Also note that this bit in context_tracking_enter():

if (state == CONTEXT_USER) {
trace_user_enter(0);
vtime_user_enter(current);
}


is related to precise time measurement of user/kernel execution times,
it's not needed by the scheduler at all, it's just exported to
tooling. It's not fundamental to the scheduler.

Thanks,

Ingo


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