From: Avi Kivity <avi@redhat.com>
To: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Cc: 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 11:49:17 +0200 [thread overview]
Message-ID: <4F61BB1D.6050209@redhat.com> (raw)
In-Reply-To: <20120315182127.07600c50.yoshikawa.takuya@oss.ntt.co.jp>
On 03/15/2012 11:21 AM, Takuya Yoshikawa wrote:
> Checking wheter iter->desc is NULL is not worth a function call
> especially when we use EPT/NPT because we know it would almost always
> be NULL.
>
> Although using "inline" like this does not look clean, we could see
> measurable performance improvements: get_dirty_log for 1GB dirty memory
> became faster by more than 10% on my test box.
>
WOW. I'd have assumed the processor deals better with this; it should
be 100% predicted branches.
But I won't argue with cold data.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2012-03-15 9:49 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 [this message]
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
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