Re: [PATCH v6 1/2] posix-timers: Prefer delivery of signals to the current thread

[Marco Elver]

On Thu, 16 Mar 2023 at 13:31, Marco Elver <elver@xxxxxxxxxx> wrote:
>
> From: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
>
> POSIX timers using the CLOCK_PROCESS_CPUTIME_ID clock prefer the main
> thread of a thread group for signal delivery.     However, this has a
> significant downside: it requires waking up a potentially idle thread.
>
> Instead, prefer to deliver signals to the current thread (in the same
> thread group) if SIGEV_THREAD_ID is not set by the user. This does not
> change guaranteed semantics, since POSIX process CPU time timers have
> never guaranteed that signal delivery is to a specific thread (without
> SIGEV_THREAD_ID set).
>
> The effect is that we no longer wake up potentially idle threads, and
> the kernel is no longer biased towards delivering the timer signal to
> any particular thread (which better distributes the timer signals esp.
> when multiple timers fire concurrently).
>
> Signed-off-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
> Suggested-by: Oleg Nesterov <oleg@xxxxxxxxxx>
> Reviewed-by: Oleg Nesterov <oleg@xxxxxxxxxx>
> Signed-off-by: Marco Elver <elver@xxxxxxxxxx>

Gentle ping...

Thanks,
-- Marco