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* timerfd question
@ 2021-11-11 22:52 Ken Brown
  2021-11-12  9:41 ` Corinna Vinschen
  0 siblings, 1 reply; 2+ messages in thread
From: Ken Brown @ 2021-11-11 22:52 UTC (permalink / raw)
  To: cygwin-devel

This question is almost certainly too vague to be answerable, but I'll try 
anyway.  Is there any obvious reason that it's bad to have two timers running 
simultaneously, one using timerfd (started via timerfd_settime) and one using a 
POSIX timer (started via timer_settime)?

Here's the context: Emacs runs timers.  Until recently it used timerfd if 
available, and otherwise a POSIX timer.  After a recent change, it starts both 
kinds of timers.  This causes a severe slowdown on Cygwin 
(https://debbugs.gnu.org/cgi/bugreport.cgi?bug=51734#32).  The easiest thing is 
just to disable that change on Cygwin, but I'd feel better understanding why 
this is a problem.

Ken

^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: timerfd question
  2021-11-11 22:52 timerfd question Ken Brown
@ 2021-11-12  9:41 ` Corinna Vinschen
  0 siblings, 0 replies; 2+ messages in thread
From: Corinna Vinschen @ 2021-11-12  9:41 UTC (permalink / raw)
  To: cygwin-developers

On Nov 11 17:52, Ken Brown wrote:
> This question is almost certainly too vague to be answerable, but I'll try
> anyway.  Is there any obvious reason that it's bad to have two timers
> running simultaneously, one using timerfd (started via timerfd_settime) and
> one using a POSIX timer (started via timer_settime)?

They don't share code, nor threads.  I don't see a reason they should
influence each other.  Both are starting timers and handle them
in independent threads.

> Here's the context: Emacs runs timers.  Until recently it used timerfd if
> available, and otherwise a POSIX timer.  After a recent change, it starts
> both kinds of timers.  This causes a severe slowdown on Cygwin
> (https://debbugs.gnu.org/cgi/bugreport.cgi?bug=51734#32).  The easiest thing
> is just to disable that change on Cygwin, but I'd feel better understanding
> why this is a problem.

A STC might be helpful.


Corinna

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2021-11-11 22:52 timerfd question Ken Brown
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