From: Davidlohr Bueso <dave@gnu.org>
To: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
lkml <linux-kernel@vger.kernel.org>, KVM <kvm@vger.kernel.org>
Subject: Re: [PATCH] KVM: VMX: add tracepoint for vpids
Date: Tue, 13 Mar 2012 11:58:05 +0100 [thread overview]
Message-ID: <1331636285.12394.4.camel@offworld> (raw)
In-Reply-To: <4F5DD140.7040605@redhat.com>
On Mon, 2012-03-12 at 12:34 +0200, Avi Kivity wrote:
> On 03/12/2012 01:29 PM, Davidlohr Bueso wrote:
> > On Mon, 2012-03-12 at 10:22 +0200, Avi Kivity wrote:
> > > On 03/11/2012 05:57 PM, Davidlohr Bueso wrote:
> > > > From: Davidlohr Bueso <dave@gnu.org>
> > > >
> > > > Add a new tracepoint for vpid allocation and freeing associated to all vCPUs.
> > > >
> > >
> > > Why?
> > >
> >
> > We have been using this tracepoint for some time now to help debug vpids
> > and simulating tagged TLB behavior and performance. This gets to be non
> > trivial when working with large amounts of guests and vCPUs.
>
> I don't follow. Can you give an example of when this tracepoint would
> be useful?
>
For example when running lots of guests with many different hardware
configurations (ept on/off, vpid on/off) I trace what vcpu has or
doesn't have a corresponding vpid associated. Perhaps this is more
useful for experimental things than actual KVM development.
next prev parent reply other threads:[~2012-03-13 10:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-11 15:57 [PATCH] KVM: VMX: add tracepoint for vpids Davidlohr Bueso
2012-03-12 8:22 ` Avi Kivity
2012-03-12 11:29 ` Davidlohr Bueso
2012-03-12 10:34 ` Avi Kivity
2012-03-13 10:58 ` Davidlohr Bueso [this message]
2012-03-13 10:10 ` Avi Kivity
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