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Groups > linux.kernel > #1589015
| From | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: tip.today - scheduler bam boom crash (cpu hotplug) |
| Date | 2017-02-27 23:50 +0100 |
| Message-ID | <tfvz5-7vd-45@gated-at.bofh.it> (permalink) |
| References | (1 earlier) <t1iim-n0-25@gated-at.bofh.it> <t1l6z-27b-53@gated-at.bofh.it> <tfsKS-5zx-19@gated-at.bofh.it> <tfsUx-5CV-1@gated-at.bofh.it> <tft4e-5G3-1@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Mon, Feb 27, 2017 at 01:50:29PM +0100, Paolo Bonzini wrote:
>
>
> On 27/02/2017 13:43, Peter Zijlstra wrote:
> > On Mon, Feb 27, 2017 at 08:30:11PM +0800, Wanpeng Li wrote:
> >
> >>> diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
> >>> index 2a5cafd..542710b 100644
> >>> --- a/arch/x86/kernel/kvmclock.c
> >>> +++ b/arch/x86/kernel/kvmclock.c
> >>> @@ -107,12 +107,12 @@ static inline void kvm_sched_clock_init(bool stable)
> >>> {
> >>> if (!stable) {
> >>> pv_time_ops.sched_clock = kvm_clock_read;
> >>> + clear_sched_clock_stable();
> >>> return;
> >>> }
> >>>
> >>> kvm_sched_clock_offset = kvm_clock_read();
> >>> pv_time_ops.sched_clock = kvm_sched_clock_read;
> >>> - set_sched_clock_stable();
> >>
> >> This results in sched clock always unstable for kvm guest since there
> >> is no invariant tsc cpuid bit exposed for kvm guest currently.
> >
> > What the heck is KVM_FEATURE_CLOCKSOURCE_STABLE_BIT /
> > PVCLOCK_TSC_STABLE_BIT about then?
>
> It checks that all the bugs in the host have been ironed out, and that
> the host itself supports invtsc.
But what does it mean if that is not so? That is, will kvm_clock_read()
still be stable even if !stable?
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Re: tip.today - scheduler bam boom crash (cpu hotplug) Wanpeng Li <kernellwp@gmail.com> - 2017-02-27 13:40 +0100
Re: tip.today - scheduler bam boom crash (cpu hotplug) Peter Zijlstra <peterz@infradead.org> - 2017-02-27 13:50 +0100
Re: tip.today - scheduler bam boom crash (cpu hotplug) Paolo Bonzini <pbonzini@redhat.com> - 2017-02-27 14:00 +0100
Re: tip.today - scheduler bam boom crash (cpu hotplug) Paolo Bonzini <pbonzini@redhat.com> - 2017-02-27 16:40 +0100
Re: tip.today - scheduler bam boom crash (cpu hotplug) Paolo Bonzini <pbonzini@redhat.com> - 2017-02-27 17:30 +0100
Re: tip.today - scheduler bam boom crash (cpu hotplug) Peter Zijlstra <peterz@infradead.org> - 2017-02-27 17:40 +0100
Re: tip.today - scheduler bam boom crash (cpu hotplug) Paolo Bonzini <pbonzini@redhat.com> - 2017-02-27 18:30 +0100
Re: tip.today - scheduler bam boom crash (cpu hotplug) Thomas Gleixner <tglx@linutronix.de> - 2017-02-27 19:10 +0100
Re: tip.today - scheduler bam boom crash (cpu hotplug) Paolo Bonzini <pbonzini@redhat.com> - 2017-02-27 20:10 +0100
Re: tip.today - scheduler bam boom crash (cpu hotplug) Peter Zijlstra <peterz@infradead.org> - 2017-02-28 00:00 +0100
Re: tip.today - scheduler bam boom crash (cpu hotplug) Wanpeng Li <kernellwp@gmail.com> - 2017-02-28 03:00 +0100
Re: tip.today - scheduler bam boom crash (cpu hotplug) Peter Zijlstra <peterz@infradead.org> - 2017-02-28 09:10 +0100
Re: tip.today - scheduler bam boom crash (cpu hotplug) Wanpeng Li <kernellwp@gmail.com> - 2017-02-28 09:20 +0100
Re: tip.today - scheduler bam boom crash (cpu hotplug) Peter Zijlstra <peterz@infradead.org> - 2017-02-27 17:50 +0100
Re: tip.today - scheduler bam boom crash (cpu hotplug) Peter Zijlstra <peterz@infradead.org> - 2017-02-27 23:50 +0100
Re: tip.today - scheduler bam boom crash (cpu hotplug) Wanpeng Li <kernellwp@gmail.com> - 2017-02-27 15:00 +0100
Re: tip.today - scheduler bam boom crash (cpu hotplug) Peter Zijlstra <peterz@infradead.org> - 2017-02-27 15:50 +0100
Re: tip.today - scheduler bam boom crash (cpu hotplug) Paolo Bonzini <pbonzini@redhat.com> - 2017-02-27 16:10 +0100
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