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From: Marcelo Tosatti <mtosatti@redhat.com>
To: Eduardo Habkost <ehabkost@redhat.com>
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	qemu-devel@nongnu.org, kvm@vger.kernel.org
Subject: Re: invtsc + migration + TSC scaling
Date: Mon, 17 Oct 2016 21:58:49 -0200	[thread overview]
Message-ID: <20161017235846.GA22657@amt.cnet> (raw)
In-Reply-To: <20161017211101.GD3275@thinpad.lan.raisama.net>

On Mon, Oct 17, 2016 at 07:11:01PM -0200, Eduardo Habkost wrote:
> On Mon, Oct 17, 2016 at 06:24:38PM +0200, Paolo Bonzini wrote:
> > On 17/10/2016 16:50, Radim Krčmář wrote:
> > > 2016-10-17 07:47-0200, Marcelo Tosatti:
> [...]
> > >> since Linux guests use kvmclock and Windows guests use Hyper-V
> > >> enlightenment, it should be fine to disable 2).
> > 
> > ... and 1 too.
> > 
> > We should also blacklist the TSC deadline timer when invtsc is not
> > available.

Actually, a nicer fix would be to check the different 
frequencies and scale the deadline relative to the difference. 

This would take care of both patched and non-patched guests.

On a related note, what was the goal of Radim's paravirtual deadline
TSC timer?

> You mean on the guest-side? On the host side, it would make
> existing VMs refuse to run.
> 
> -- 
> Eduardo

  reply	other threads:[~2016-10-17 23:59 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-14 21:20 invtsc + migration + TSC scaling Eduardo Habkost
2016-10-17  9:47 ` Marcelo Tosatti
2016-10-17 14:50   ` Radim Krčmář
2016-10-17 16:24     ` Paolo Bonzini
2016-10-17 21:11       ` Eduardo Habkost
2016-10-17 23:58         ` Marcelo Tosatti [this message]
2016-10-18 13:41           ` Paolo Bonzini
2016-10-18 17:09             ` Marcelo Tosatti
2016-10-18 20:52               ` Radim Krčmář
2016-10-18 21:05                 ` Eduardo Habkost
2016-10-19 13:27                   ` Radim Krčmář
2016-10-19 13:55                     ` Eduardo Habkost
2016-10-19 15:42                       ` Radim Krčmář
2016-10-19 17:42                         ` Eduardo Habkost
2016-10-18 13:48           ` Radim Krčmář
2016-10-18 13:36       ` Radim Krčmář
2016-10-18 13:38         ` Radim Krčmář
2016-10-17 17:20     ` Marcelo Tosatti
2016-10-18 13:27       ` Radim Krčmář
2016-10-18  9:04     ` [Qemu-devel] " Dr. David Alan Gilbert

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