Messages in this thread | | | From | "Li,Rongqing" <> | Subject | 答复: [PATCH] [RFC] kvm: x86: emulate APERF /MPERF registers | Date | Sun, 26 Apr 2020 03:24:13 +0000 |
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> -----邮件原件----- > 发件人: Paolo Bonzini [mailto:pbonzini@redhat.com] > 发送时间: 2020年4月25日 0:30 > 收件人: Jim Mattson <jmattson@google.com>; Sean Christopherson > <sean.j.christopherson@intel.com> > 抄送: Peter Zijlstra <peterz@infradead.org>; Li,Rongqing > <lirongqing@baidu.com>; LKML <linux-kernel@vger.kernel.org>; kvm list > <kvm@vger.kernel.org>; the arch/x86 maintainers <x86@kernel.org>; H . > Peter Anvin <hpa@zytor.com>; Borislav Petkov <bp@alien8.de>; Ingo Molnar > <mingo@redhat.com>; Thomas Gleixner <tglx@linutronix.de>; Joerg Roedel > <joro@8bytes.org>; Wanpeng Li <wanpengli@tencent.com>; Vitaly Kuznetsov > <vkuznets@redhat.com> > 主题: Re: [PATCH] [RFC] kvm: x86: emulate APERF/MPERF registers > > On 24/04/20 18:25, Jim Mattson wrote: > >> Assuming we're going forward with this, at an absolute minimum the > >> RDMSRs need to be wrapped with checks on host _and_ guest support for > >> the emulated behavior. Given the significant overhead, this might > >> even be something that should require an extra opt-in from userspace to > enable. > > > > I would like to see performance data before enabling this unconditionally. > > I wouldn't want this to be enabled unconditionally anyway, because you need to > take into account live migration to and from processors that do not have > APERF/MPERF support. > > Paolo
I will add a kvm parameter to consider whether enable MPERF/APERF emulations, and make default value to false
Thanks
-Li
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