* Rik van Riel <[email protected]> wrote:
> On 05/01/2015 12:37 PM, Ingo Molnar wrote:
>
> > 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.
>
> Any objections to the idea from the other thread to simply keep the
> time accumulating in buffers in local_clock() units, and only update
> the task vtime once a second or so?
So I really think per syscall overhead is the wrong thing to do for
anything that a common distro enables.
I see very little use for such precise, high-freq measurements on
normal systems - and abnormal systems could enable it dynamically just
like they can enable syscall auditing.
I.e. I don't mind the occasional crazy piece of code, as long as it
does not hurt the innocent.
Thanks,
Ingo
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