Messages in this thread | | | Date | Fri, 1 May 2015 18:37:09 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH 3/3] context_tracking,x86: remove extraneous irq disable & enable from context tracking on syscall entry |
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* 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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