On Mon, Apr 28, 2014 at 1:42 PM, Stepan Kasal <kasal@xxxxxx> wrote:
> From: Paolo Bonzini <bonzini@xxxxxxx>
> Date: Mon, 21 May 2012 09:52:42 +0200
>
> Backported from Gnulib.
>
> 2012-05-21 Paolo Bonzini <bonzini@xxxxxxx>
>
> poll/select: prevent busy-waiting. SwitchToThread() only gives away
> the rest of the current time slice to another thread in the current
> process. So if the thread that feeds the file decscriptor we're
> polling is not in the current process, we get busy-waiting.
> * lib/poll.c: Use SleepEx(1, TRUE) instead of SwitchToThread().
> Patch from Theodore Leblond.
> * lib/select.c: Split polling out of the loop that sets the output
> fd_sets. Check for zero result and loop if the wait timeout is
> infinite.
>
> Signed-off-by: Stepan Kasal <kasal@xxxxxx>
> ---
> compat/poll/poll.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/compat/poll/poll.c b/compat/poll/poll.c
> index 31163f2..a9b41d8 100644
> --- a/compat/poll/poll.c
> +++ b/compat/poll/poll.c
> @@ -605,7 +605,7 @@ restart:
>
> if (!rc && timeout == INFTIM)
> {
> - SwitchToThread();
> + SleepEx (1, TRUE);
> goto restart;
> }
>
> --
> 1.9.2.msysgit.0.158.g6070cee
>
Thanks for taking the effort!
Acked-by: Erik Faye-Lund <kusmabite@xxxxxxxxx>
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