Re: [Qemu-devel] [PATCH] cpus: reset throttle_thread_scheduled after sleep

[Juan Quintela <quintela@redhat.com>]

Felipe Franciosi <felipe@nutanix.com> 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 <felipe@nutanix.com>
> Signed-off-by: Malcolm Crossley <malcolm@nutanix.com>

Reviewed-by: Juan Quintela <quintela@redhat.com>

Paolo, I think that the analisys makes sense.

Should you pull this patch, or do you want me to pull it?

Thanks, Juan.