From: Avi Kivity <avi@redhat.com>
To: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>,
Marcelo Tosatti <mtosatti@redhat.com>, KVM <kvm@vger.kernel.org>,
quintela@redhat.com, qemu-devel@nongnu.org,
Takuya Yoshikawa <takuya.yoshikawa@gmail.com>
Subject: Re: [PATCH 0/4] KVM: Dirty logging optimization using rmap
Date: Thu, 01 Dec 2011 17:18:06 +0200 [thread overview]
Message-ID: <4ED79AAE.8000201@redhat.com> (raw)
In-Reply-To: <4ED5BC03.5000901@oss.ntt.co.jp>
On 11/30/2011 07:15 AM, Takuya Yoshikawa wrote:
> (2011/11/30 14:02), Takuya Yoshikawa wrote:
>
>> IIUC, even though O(1) is O(1) at the timing of GET DIRTY LOG, it
>> needs O(N) write
>> protections with respect to the total number of dirty pages:
>> distributed, but
>> actually each page fault, which should be logged, does some write
>> protection?
>
> Sorry, was not precise. It depends on the level, and not completely
> distributed.
> But I think it is O(N), and the total number of costs will not change
> so much,
> I guess.
That's true. But some applications do require low latency, and the
current code can impose a lot of time with the mmu spinlock held.
The total amount of work actually increases slightly, from O(N) to O(N
log N), but since the tree is so wide, the overhead is small.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2011-12-01 15:18 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-14 9:20 [PATCH 0/4] KVM: Dirty logging optimization using rmap Takuya Yoshikawa
2011-11-14 9:21 ` [PATCH 1/4] KVM: MMU: Clean up BUG_ON() conditions in rmap_write_protect() Takuya Yoshikawa
2011-11-14 9:22 ` [PATCH 2/4] KVM: MMU: Split gfn_to_rmap() into two functions Takuya Yoshikawa
2011-11-14 9:23 ` [PATCH 3/4] KVM: Count the number of dirty pages for dirty logging Takuya Yoshikawa
2011-11-14 10:07 ` Avi Kivity
2011-11-14 10:24 ` Avi Kivity
2011-12-20 4:29 ` Takuya Yoshikawa
2011-12-23 11:14 ` Marcelo Tosatti
2011-12-24 2:52 ` Takuya Yoshikawa
2011-12-27 13:50 ` Marcelo Tosatti
2011-12-27 14:03 ` Avi Kivity
2011-12-27 15:03 ` Takuya Yoshikawa
2011-12-27 15:06 ` Avi Kivity
2011-12-27 15:15 ` Takuya Yoshikawa
2011-12-27 15:18 ` Avi Kivity
2011-11-14 9:24 ` [PATCH 4/4] KVM: Optimize dirty logging by rmap_write_protect() Takuya Yoshikawa
2011-11-14 10:22 ` Avi Kivity
2011-11-14 10:29 ` Takuya Yoshikawa
2011-11-14 10:25 ` [PATCH 0/4] KVM: Dirty logging optimization using rmap Avi Kivity
2011-11-14 10:56 ` Takuya Yoshikawa
2011-11-14 12:39 ` Avi Kivity
2011-11-16 4:28 ` Takuya Yoshikawa
2011-11-16 9:06 ` Avi Kivity
2011-11-29 10:01 ` Xiao Guangrong
2011-11-29 10:09 ` Xiao Guangrong
2011-11-29 10:35 ` Takuya Yoshikawa
2011-11-29 11:20 ` Avi Kivity
2011-11-29 11:56 ` Xiao Guangrong
2011-11-29 12:01 ` Avi Kivity
2011-11-29 14:03 ` Avi Kivity
2011-11-30 5:02 ` Takuya Yoshikawa
2011-11-30 5:15 ` Takuya Yoshikawa
2011-12-01 15:18 ` Avi Kivity [this message]
2011-12-03 4:37 ` Takuya Yoshikawa
2011-12-04 10:20 ` Avi Kivity
2011-11-30 7:10 ` Xiao Guangrong
2011-11-30 7:03 ` Xiao Guangrong
2011-12-01 15:11 ` Avi Kivity
2011-11-16 8:17 ` Takuya Yoshikawa
2011-11-17 9:28 ` Avi Kivity
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