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
