[API] How many time to be context-switched?

[Joel Fernandes]

Please reply always to kernelnewbies.

On Nov 27, 2016 11:09 AM, "Ricardo Biehl" <rbpoficial at gmail.com> wrote:
>
> 2016-11-27 16:01 GMT-02:00, Joel Fernandes <agnel.joel at gmail.com>:
> > On Nov 27, 2016 9:44 AM, "Ricardo Biehl" <rbpoficial at gmail.com> wrote:
> >>
> >>         As a question I've made on Stackexchange
> >>         <
> >
http://stackoverflow.com/questions/40579919/how-many-time-to-be-context-switched
> >>:
> >>
> >> I'm developing a real-time program where scheduler's context-switches
> >> might interfere its performance.
> >> ---
> >> Suppose I need to do many consecutive (but optional) operations (I
> >> mean I'm able to cancel some of them) of the same type in every
> >> execution of a timer-oriented signal handler.
> >> Could I check how much time left until my thread get context-switched?
> >> [...] and then I can cancel/jump some operations for a better
> >> performance at all.
> >>
> >> If yes, how can I do it (in C code)?
> >>
> >
> > If you use SCHED_FIFO, then at the right RT priority level, you should
not
> > context switch anyway. Time quantas apply only to regular CFS tasks or
when
> > RT throttling is activated.
> >
> > Also note that interrupts and softirqs cause variability and
interruptions
> > no matter what you do or how you schedule.
> >
> > J.
>
> Thank you Joel!
>
> Another small question: Can I use pthread_cond_signal[broadcast]() (a
> non async-signal-safe function) inside signal handler, given I know
> pthread_cond_wait() hasn't been called at the same time?

Should be, as per docs it wakes up *IF* any threads are blocked on cond.

Thanks,
Joel

> >
> >> Huge thanks!
> >>
> >> --
> >> Ricardo Biehl Pasquali
> >>
> >> _______________________________________________
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> >
>
>
> --
> Ricardo Biehl Pasquali
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