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Re: [Qemu-devel] [PATCH] cpus: reset throttle_thread_scheduled after sle
From: |
Juan Quintela |
Subject: |
Re: [Qemu-devel] [PATCH] cpus: reset throttle_thread_scheduled after sleep |
Date: |
Wed, 07 Jun 2017 18:26:39 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/25.2 (gnu/linux) |
Felipe Franciosi <address@hidden> wrote:
> Currently, the throttle_thread_scheduled flag is reset back to 0 before
> sleeping (as part of the throttling logic). Given that throttle_timer
> (well, any timer) may tick with a slight delay, it so happens that under
> heavy throttling (ie. close or on CPU_THROTTLE_PCT_MAX) the tick may
> schedule a further cpu_throttle_thread() work item after the flag reset,
> but before the previous sleep completed. This results on the vCPU thread
> sleeping continuously for potentially several seconds in a row.
>
> The chances of that happening can be drastically minimised by resetting
> the flag after the sleep.
>
> Signed-off-by: Felipe Franciosi <address@hidden>
> Signed-off-by: Malcolm Crossley <address@hidden>
Reviewed-by: Juan Quintela <address@hidden>
Paolo, I think that the analisys makes sense.
Should you pull this patch, or do you want me to pull it?
Thanks, Juan.