From: Avi Kivity <avi@redhat.com>
To: Takuya Yoshikawa <takuya.yoshikawa@gmail.com>
Cc: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>,
mtosatti@redhat.com, kvm@vger.kernel.org
Subject: Re: [PATCH 3/3] KVM: MMU: Separate trivial NULL check out from rmap_get_next()
Date: Tue, 20 Mar 2012 13:56:59 +0200 [thread overview]
Message-ID: <4F68708B.8080507@redhat.com> (raw)
In-Reply-To: <20120320153713.a952558c3a3d84a686665261@gmail.com>
On 03/20/2012 08:37 AM, Takuya Yoshikawa wrote:
> On Thu, 15 Mar 2012 15:46:31 +0200
> Avi Kivity <avi@redhat.com> wrote:
>
> > You can look at what's happening by doing
> >
> > perf record -a -f
> > perf report
> >
> > using the TUI, select 'annotate rmap_get_next'
> >
> > You should see where the time is spent.
> >
>
> Since the default sampling rate was not enough to get consistent numbers,
> I raised the frequency to 50K/sec; so there was surely some overheads
> during that sampling.
>
> From the result below, it seems to be the prologue and epilogue on which
> we spent most of our time.
>
>
I can only assume that the cpu is processing these instructions
perfectly and each is taking 1 cycle (or less). I don't see how else we
can arrive at such results.
--
error compiling committee.c: too many arguments to function
prev parent reply other threads:[~2012-03-20 11:57 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-15 9:18 [PATCH 0/3] KVM: MMU: Improve rmap handling Takuya Yoshikawa
2012-03-15 9:19 ` [PATCH 1/3] KVM: MMU: Make pte_list_desc fit cache lines well Takuya Yoshikawa
2012-03-15 9:22 ` Avi Kivity
2012-03-15 9:20 ` [PATCH 2/3] KVM: MMU: Improve iteration over sptes linked by rmap Takuya Yoshikawa
2012-03-15 9:44 ` Avi Kivity
2012-03-15 10:25 ` Takuya Yoshikawa
2012-03-15 9:21 ` [PATCH 3/3] KVM: MMU: Separate trivial NULL check out from rmap_get_next() Takuya Yoshikawa
2012-03-15 9:49 ` Avi Kivity
2012-03-15 10:15 ` Takuya Yoshikawa
2012-03-15 12:01 ` Avi Kivity
2012-03-15 13:41 ` Takuya Yoshikawa
2012-03-15 13:45 ` Avi Kivity
2012-03-15 13:46 ` Avi Kivity
2012-03-20 6:37 ` Takuya Yoshikawa
2012-03-20 11:56 ` Avi Kivity [this message]
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