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Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests

From "Michael S. Tsirkin" <mst@redhat.com>
Newsgroups linux.kernel
Subject Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests
Date 2017-03-22 15:20 +0100
Message-ID <tnPhg-3Fu-31@gated-at.bofh.it> (permalink)
References <tnAUV-1rR-15@gated-at.bofh.it> <tnC0G-2r8-7@gated-at.bofh.it> <tnOEy-37h-23@gated-at.bofh.it> <tnPhg-3Fu-33@gated-at.bofh.it>
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On Wed, Mar 22, 2017 at 10:10:05AM -0400, Gabriel L. Somlo wrote:
> On Wed, Mar 22, 2017 at 03:35:18PM +0200, Michael S. Tsirkin wrote:
> > On Tue, Mar 21, 2017 at 05:02:25PM -0700, Nadav Amit wrote:
> > > 
> > > > On Mar 21, 2017, at 3:51 PM, Gabriel Somlo <gsomlo@gmail.com> wrote:
> > > > 
> > > > And I get the exact same results on the MacBookAir4,2 (which exhibits
> > > > no freezing or extreme sluggishness when running OS X 10.7 smp with
> > > > Michael's KVM MWAIT-in-L1 patch)...
> > > 
> > > Sorry for my confusion. I didn’t read the entire thread and thought that
> > > the problem is spurious wake-ups.
> > > 
> > > Since that is not the case, I would just suggest two things that you can
> > > freely ignore:
> > > 
> > > 1. According to the SDM, when an interrupt is delivered, the interrupt
> > > is only delivered on the following instruction, so you may consider
> > > skipping the MWAIT first.
> > > 
> > > 2. Perhaps the CPU changes for some reason GUEST_ACTIVITY_STATE (which
> > > is not according to the SDM).
> > > 
> > > That is it. No more BS from me.
> > > 
> > > Nadav
> > 
> > Intersting. I found this errata:
> > A REP STOS/MOVS to a MONITOR/MWAIT Address Range May Prevent Triggering of
> > the Monitoring Hardware
> 
> Any way to tell if they mean that for L0, or L>=1, or all of them?
> 
> > Could the macbook CPU be affected?
> 
> I ran a grep on the log file I collected when disassembling
> AppleIntelCPUPowerManagement.kext (where the MWAIT-based idle
> thread lives) a few days ago, and didn't find any "rep stos" or
> "rep movs" instances.
> 

Right but that would be on the waking side, not the one
that does mwait.

-- 
MST

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Thread

[PATCH v5 untested] kvm: better MWAIT emulation for guests "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-15 22:30 +0100
  Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Gabriel L. Somlo" <gsomlo@gmail.com> - 2017-03-16 00:40 +0100
    Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-16 00:50 +0100
      Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Gabriel L. Somlo" <gsomlo@gmail.com> - 2017-03-16 14:30 +0100
        Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests Radim Krčmář <rkrcmar@redhat.com> - 2017-03-16 15:10 +0100
          Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Gabriel L. Somlo" <gsomlo@gmail.com> - 2017-03-16 17:00 +0100
            Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests Radim Krčmář <rkrcmar@redhat.com> - 2017-03-16 17:00 +0100
              Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Gabriel L. Somlo" <gsomlo@gmail.com> - 2017-03-16 17:30 +0100
        Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-16 15:10 +0100
          Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Gabriel L. Somlo" <gsomlo@gmail.com> - 2017-03-16 16:00 +0100
            Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-16 16:30 +0100
            Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests Radim Krčmář <rkrcmar@redhat.com> - 2017-03-16 16:40 +0100
              Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests Radim Krčmář <rkrcmar@redhat.com> - 2017-03-16 17:10 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Gabriel L. Somlo" <gsomlo@gmail.com> - 2017-03-16 17:50 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-16 18:30 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Gabriel L. Somlo" <gsomlo@gmail.com> - 2017-03-16 18:50 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-16 19:40 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-16 20:30 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Gabriel L. Somlo" <gsomlo@gmail.com> - 2017-03-16 21:20 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Gabriel L. Somlo" <gsomlo@gmail.com> - 2017-03-16 22:20 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-17 03:10 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Gabriel L. Somlo" <gsomlo@gmail.com> - 2017-03-17 14:40 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-21 04:30 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests Radim Krčmář <rkrcmar@redhat.com> - 2017-03-21 18:10 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests Nadav Amit <nadav.amit@gmail.com> - 2017-03-21 18:40 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests Radim Krčmář <rkrcmar@redhat.com> - 2017-03-21 20:30 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests Gabriel Somlo <gsomlo@gmail.com> - 2017-03-22 00:00 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests Nadav Amit <nadav.amit@gmail.com> - 2017-03-22 01:10 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-22 14:40 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-22 15:20 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Gabriel L. Somlo" <gsomlo@gmail.com> - 2017-03-22 15:20 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Gabriel L. Somlo" <gsomlo@gmail.com> - 2017-03-16 20:30 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests Radim Krčmář <rkrcmar@redhat.com> - 2017-03-16 18:30 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Gabriel L. Somlo" <gsomlo@gmail.com> - 2017-03-16 18:40 +0100
              Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Gabriel L. Somlo" <gsomlo@gmail.com> - 2017-03-16 17:20 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-16 17:50 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Gabriel L. Somlo" <gsomlo@gmail.com> - 2017-03-16 18:00 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Gabriel L. Somlo" <gsomlo@gmail.com> - 2017-03-16 18:00 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-16 18:20 +0100
                Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests Radim Krčmář <rkrcmar@redhat.com> - 2017-03-16 18:40 +0100
  Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests Joerg Roedel <joro@8bytes.org> - 2017-03-21 17:20 +0100
    Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-21 19:50 +0100
  Re: [PATCH v5 untested] kvm: better MWAIT emulation for guests Alexander Graf <agraf@suse.de> - 2017-03-27 15:40 +0200

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