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From: Paolo Bonzini <pbonzini@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: kvm@vger.kernel.org, Luiz Capitulino <lcapitulino@redhat.com>,
	Rik van Riel <riel@redhat.com>, Radim Krcmar <rkrcmar@redhat.com>
Subject: Re: [patch 3/3] KVM: x86: add tracepoint to wait_lapic_expire
Date: Tue, 16 Dec 2014 13:19:07 +0100	[thread overview]
Message-ID: <5490233B.10109@redhat.com> (raw)
In-Reply-To: <20141216121556.GA28966@amt.cnet>



On 16/12/2014 13:15, Marcelo Tosatti wrote:
> > Let's add guest_tsc - tsc_deadline to the tracepoint.  This should
> > simplify the tuning of the parameter.
> 
> total_delay is very close to that, except the summands are 
> 
>     1000 + 1000 + ... + "remainder"
> 
> Yes?

Almost: guest_tsc - tsc_deadline will be negative if the vmentry
overshot the original tsc_deadline.  In that case, total_delay will be zero.

> BTW its very easy to tune the parameter with the kvm-unit-test test
> (the optimal value is clear). I'll write a document.

Nice benefit of the test. :)

Paolo

  reply	other threads:[~2014-12-16 12:19 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-15 22:06 [patch 0/3] KVM: add option to advance tscdeadline hrtimer expiration (v4) Marcelo Tosatti
2014-12-15 22:06 ` [patch 1/3] KVM: x86: add method to test PIR bitmap vector Marcelo Tosatti
2014-12-15 22:06 ` [patch 2/3] KVM: x86: add option to advance tscdeadline hrtimer expiration Marcelo Tosatti
2014-12-16 14:34   ` Paolo Bonzini
2014-12-16 15:13     ` Marcelo Tosatti
2014-12-16 15:18       ` Paolo Bonzini
2014-12-15 22:06 ` [patch 3/3] KVM: x86: add tracepoint to wait_lapic_expire Marcelo Tosatti
2014-12-16  9:03   ` Paolo Bonzini
2014-12-16 12:15     ` Marcelo Tosatti
2014-12-16 12:19       ` Paolo Bonzini [this message]
  -- strict thread matches above, loose matches on Subject: below --
2014-12-16 14:08 [patch 0/3] KVM: add option to advance tscdeadline hrtimer expiration (v5) Marcelo Tosatti
2014-12-16 14:08 ` [patch 3/3] KVM: x86: add tracepoint to wait_lapic_expire Marcelo Tosatti
2014-12-17 15:06   ` Radim Krcmar
2014-12-23 20:58 [patch 0/3] KVM: add option to advance tscdeadline hrtimer expiration (v6) Marcelo Tosatti
2014-12-23 20:58 ` [patch 3/3] KVM: x86: add tracepoint to wait_lapic_expire Marcelo Tosatti

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