From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751834AbeEDXot (ORCPT ); Fri, 4 May 2018 19:44:49 -0400 Received: from mail-ot0-f196.google.com ([74.125.82.196]:32851 "EHLO mail-ot0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751710AbeEDXor (ORCPT ); Fri, 4 May 2018 19:44:47 -0400 X-Google-Smtp-Source: AB8JxZpnALIQpyFVCTqwF8pWDckDIlblaxFLyL5/9B3H9voZNh0dEquY5C2ZN3kI5PgY+VJ9JHx+/lOpSVh2iNnvLdk= MIME-Version: 1.0 In-Reply-To: <1525131328-27086-1-git-send-email-wanpengli@tencent.com> References: <1525131328-27086-1-git-send-email-wanpengli@tencent.com> From: Wanpeng Li Date: Sat, 5 May 2018 07:44:46 +0800 Message-ID: Subject: Re: [PATCH v2] KVM: X86: Limit timer frequency to 200ms To: LKML , kvm Cc: Paolo Bonzini , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Anthoine Bourgeois , Darren Kenny Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mail.home.local id w44NiwvB021126 ping, 2018-05-01 7:35 GMT+08:00 Wanpeng Li : > From: Wanpeng Li > > 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. > > Reported-by: Anthoine Bourgeois > Suggested-by: Paolo Bonzini > Reviewed-by: Darren Kenny > Cc: Paolo Bonzini > Cc: Radim Krčmář > Cc: Anthoine Bourgeois > Cc: Darren Kenny > Signed-off-by: Wanpeng Li > --- > v1 -> v2: > * update patch subject and description > > arch/x86/kvm/x86.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 51ecd38..dc47073 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -114,7 +114,7 @@ module_param(ignore_msrs, bool, S_IRUGO | S_IWUSR); > static bool __read_mostly report_ignored_msrs = true; > module_param(report_ignored_msrs, bool, S_IRUGO | S_IWUSR); > > -unsigned int min_timer_period_us = 500; > +unsigned int min_timer_period_us = 200; > module_param(min_timer_period_us, uint, S_IRUGO | S_IWUSR); > > static bool __read_mostly kvmclock_periodic_sync = true; > -- > 2.7.4 >