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From: Takuya Yoshikawa <takuya.yoshikawa@gmail.com>
To: Avi Kivity <avi@redhat.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: Thu, 15 Mar 2012 22:41:42 +0900	[thread overview]
Message-ID: <20120315224142.67713f557239116a99cd18af@gmail.com> (raw)
In-Reply-To: <4F61DA07.4010200@redhat.com>

Avi Kivity <avi@redhat.com> wrote:

> > What I checked was:
> >
> > original   with-patch2   with-patch3
> > 8.7ms      8.5ms         7.5ms
> 
> What's the per-call numbers?

I did not look into details at that time.
I will try to see more details later if possible!

> What I mean is, modern cpus effectively inline simple function calls by
> predicting the call, and branchs within the function, and the return, so
> they don't have to stop their pipelines at any of these points.  But
> again, the numbers talk louder than speculation about cpu architecture.

I need to update my knowledge, thank you!

Anyway I will re-check if we can achieve the same performance with a bit
cleaner implementation.


	Takuya

  reply	other threads:[~2012-03-15 13:41 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 [this message]
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

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