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

[Paolo Bonzini <pbonzini@redhat.com>]

On 07/06/2017 18:26, Juan Quintela wrote:
> 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?

I've already included in my jinxed (now at v6) pull request.

Paolo