From: Avi Kivity <avi@redhat.com>
To: Gleb Natapov <gleb@redhat.com>
Cc: mtosatti@redhat.com, kvm@vger.kernel.org
Subject: Re: [PATCH] KVM: emulator: do not needlesly sync registers from emulator ctxt to vcpu
Date: Wed, 30 Mar 2011 15:46:58 +0200 [thread overview]
Message-ID: <4D933452.5020108@redhat.com> (raw)
In-Reply-To: <20110330134350.GA7766@redhat.com>
On 03/30/2011 03:43 PM, Gleb Natapov wrote:
> On Wed, Mar 30, 2011 at 03:41:09PM +0200, Avi Kivity wrote:
> > On 03/30/2011 03:36 PM, Gleb Natapov wrote:
> > >>
> > >> It's wierd. Do you get perf hits in the copying?
> > >>
> > >How can I check. The memcpy is inlined.
> > >
> >
> > perf annotate x86_emulate_instruction
> >
> > (newer perf allows you to get there interactively from 'perf report')
> >
> > >> Copying a couple of hot cache lines shouldn't take any measurable
> Ah, forgot about it:
>
> First one:
> 27.71 : 1179f: f3 a5 rep movsl %ds:(%rsi),%es:(%rdi)
>
> Second one:
> 32.68 : 11888: f3 a5 rep movsl %ds:(%rsi),%es:(%rdi)
>
Okay, I'm convinced.
(looks like a missed optimization, should use rep movsq there)
--
error compiling committee.c: too many arguments to function
prev parent reply other threads:[~2011-03-30 13:47 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-29 12:08 [PATCH] KVM: emulator: do not needlesly sync registers from emulator ctxt to vcpu Gleb Natapov
2011-03-30 10:38 ` Avi Kivity
2011-03-30 10:47 ` Gleb Natapov
2011-03-30 10:50 ` Avi Kivity
2011-03-30 11:22 ` Gleb Natapov
2011-03-30 11:43 ` Gleb Natapov
2011-03-30 12:12 ` Avi Kivity
2011-03-30 12:12 ` Avi Kivity
2011-03-30 12:17 ` Avi Kivity
2011-03-30 12:48 ` Gleb Natapov
2011-03-30 13:26 ` Gleb Natapov
2011-03-30 13:29 ` Avi Kivity
2011-03-30 13:36 ` Gleb Natapov
2011-03-30 13:41 ` Avi Kivity
2011-03-30 13:43 ` Gleb Natapov
2011-03-30 13:46 ` Avi Kivity [this message]
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