Re: [PATCH] sched: introduce configurable delay before entering idle

[Boris Ostrovsky]

On 5/13/19 7:51 AM, Raslan, KarimAllah wrote:
> On Mon, 2019-05-13 at 07:31 -0400, Konrad Rzeszutek Wilk wrote:
>> On May 13, 2019 5:20:37 AM EDT, Wanpeng Li <kernellwp@xxxxxxxxx> wrote:
>>> On Wed, 8 May 2019 at 02:57, Marcelo Tosatti <mtosatti@xxxxxxxxxx>
>>> wrote:
>>>>
>>>>
>>>> Certain workloads perform poorly on KVM compared to baremetal
>>>> due to baremetal's ability to perform mwait on NEED_RESCHED
>>>> bit of task flags (therefore skipping the IPI).
>>> KVM supports expose mwait to the guest, if it can solve this?
>>>
>>
>> There is a bit of problem with that. The host will see 100% CPU utilization even if the guest is idle and taking long naps..
>>
>> Which depending on your dashboard can look like the machine is on fire.
> This can also be fixed. I have a patch that kind of expose proper informationÂ
> about the *real* utilization here if that would be help.

Yes, that would certainly be interesting to see. Thanks.


--boris