domain switch

Leandro Bucci guestleandro11 at gmail.com
Sun Jan 3 12:20:36 CET 2021


perfect thank you so much for the explanation

Il dom 3 gen 2021, 12:06 Philippe Gerum <rpm at xenomai.org> ha scritto:

>
> Leandro Bucci <guestleandro11 at gmail.com> writes:
>
> > is it possible to have the same thing for tasks instead of threads?
> >
>
> task == thread
>
> > Il dom 3 gen 2021, 11:31 Philippe Gerum <rpm at xenomai.org> ha scritto:
> >
> >>
> >> steve freyder via Xenomai <xenomai at xenomai.org> writes:
> >>
> >> > Right.
> >> >
> >> >
> >> > AKA, "mode switch", a switch from "primary mode" to "secondary mode",
> >> > or vice versa.
> >> >
> >> > One place you can find that information is in:
> >> >
> >> > /proc/xenomai/sched/acct
> >> >
> >> > there are two fields MSW, and CSW which count mode/context switches
> >> > per-process. This requires an open, a read loop to locate the desired
> >> > pid and extract the desired information, then either rewind or
> >> > close/reopen to do it again - all of which will almost surely generate
> >> > more mode/context switching.
> >> >
> >>
> >> If that helps, there is also the option of getting the thread stats by
> >> program, using int cobalt_thread_stat(pid_t pid, struct
> >> cobalt_threadstat *stat), declared in sys/cobalt.h. pid refers to a
> >> thread identifier (as obtained from gettid(2) in the context of the
> >> target thread). It must refer to a Cobalt thread, otherwise the call
> >> would fail with -ESRCH.
> >>
> >> The mode switch count is present in the returned information block
> >> (->msw). cobalt_thread_stat() would not cause any mode switch. It can be
> >> called by any thread regardless of its type (i.e. regular or Cobalt).
> >>
> >> --
> >> Philippe.
> >>
>
>
> --
> Philippe.
>


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