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From: Paolo Bonzini <pbonzini@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>, kvm list <kvm@vger.kernel.org>
Subject: Re: Non-exiting rdpmc on KVM guests?
Date: Wed, 22 Apr 2015 23:05:25 +0200	[thread overview]
Message-ID: <55380D15.7010902@redhat.com> (raw)
In-Reply-To: <20150421205139.GA2898@worktop.Skamania.guest>



On 21/04/2015 22:51, Peter Zijlstra wrote:
> > However, if you take into account that RDPMC can also be used
> > to read an inactive counter, and that multiple guests "fight" for the
> > same host counters, it's even harder to ensure that the guest counter
> > indices match those on the host.
>
> That doesn't make sense, only a single vcpu task will ever run at any
> one time.

Right, but it puts more pressure on the scheduler which could end up
going more often through the slow path.

Paolo

      parent reply	other threads:[~2015-04-22 21:05 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-21  0:47 Non-exiting rdpmc on KVM guests? Andy Lutomirski
2015-04-21 15:05 ` Peter Zijlstra
2015-04-21 16:32   ` Paolo Bonzini
2015-04-21 20:51     ` Peter Zijlstra
2015-04-21 21:10       ` Andy Lutomirski
2015-04-22 15:26         ` Peter Zijlstra
2015-04-22 21:05       ` Paolo Bonzini [this message]

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