linux-kernel - Re: [PATCH v2] KVM: X86: Limit timer frequency to 200ms

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Date:   Sat, 5 May 2018 19:03:18 +0800
From:   Wanpeng Li <kernellwp@...il.com>
To:     Jan Kiszka <jan.kiszka@....de>
Cc:     LKML <linux-kernel@...r.kernel.org>, kvm <kvm@...r.kernel.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Anthoine Bourgeois <anthoine.bourgeois@...de-group.com>,
        Darren Kenny <darren.kenny@...cle.com>
Subject: Re: [PATCH v2] KVM: X86: Limit timer frequency to 200ms

2018-05-05 16:36 GMT+08:00 Jan Kiszka <jan.kiszka@....de>:
> On 2018-05-05 01:44, Wanpeng Li wrote:
>> ping,
>> 2018-05-01 7:35 GMT+08:00 Wanpeng Li <kernellwp@...il.com>:
>>> From: Wanpeng Li <wanpengli@...cent.com>
>>>
>>> Anthoine reported:
>>>  The period used by Windows change over time but it can be 1 milliseconds
>>>  or less. I saw the limit_periodic_timer_frequency print so 500
>>>  microseconds is sometimes reached.
>>>
>>> As suggested by Paolo, lower the timer frequency limit to a
>>> smaller interval of 200 ms (5000 Hz) to leave some headroom. This
>>> is required due to Windows 10 changing the scheduler tick limit
>>> from 1024 Hz to 2048 Hz.
>
> "... lower the *default* timer frequency limit to a smaller interval of
> 200 *us* ..." - same for the subject.

Thanks Jan, I will update it.

Regards,
Wanpeng Li