From: Yoshiaki Tamura <tamura.yoshiaki@lab.ntt.co.jp>
To: Avi Kivity <avi@redhat.com>
Cc: kvm@vger.kernel.org, qemu-devel@nongnu.org,
anthony@codemonkey.ws, ohmura.kei@lab.ntt.co.jp
Subject: Re: [PATCH 0/6] qemu-kvm: Introduce bit-based phys_ram_dirty, and bit-based dirty page checker.
Date: Tue, 16 Mar 2010 22:41:21 +0900 [thread overview]
Message-ID: <4B9F8A81.3060005@lab.ntt.co.jp> (raw)
In-Reply-To: <4B9F836E.9070504@redhat.com>
Avi Kivity wrote:
> On 03/16/2010 12:53 PM, Yoshiaki Tamura wrote:
>> Experimental results:
>> Cond1: 1.9 ~ 61 times speed up
>> Cond2: 1.9 ~ 56 times speed up
>> Cond3: 1.9 ~ 59 times speed up
>> Cond4: 1.7 ~ 59 times speed up
>
> Impressive results. What's the typical speedup? Closer to 1.9 or 61?
To be honest, I thought the result above was too vague...
The speed up grows when the number of dirty pages decreases.
Let me paste the snipped actual data measured during live migration on Cond1.
This result is measured with cpu_get_real_ticks(), so the values should be in
raw ticks.
135200 dirty pages: orig.2488419, bitbased.1251171, ratio.1.99
...
98346 dirty pages: orig.3580533, bitbased.1386918, ratio.2.58
...
54865 dirty pages: orig.4220865, bitbased.984924, ratio.4.29
...
27883 dirty pages: orig.4088970, bitbased.514602, ratio.7.95
...
11541 dirty pages: orig.3854277, bitbased.220410, ratio.17.49
...
8117 dirty pages: orig.4041765, bitbased.175446, ratio.23.04
3231 dirty pages: orig.3337083, bitbased.105921, ratio.31.51
2401 dirty pages: orig.4103469, bitbased.89406, ratio.45.90
1595 dirty pages: orig.4028949, bitbased.78570, ratio.51.28
756 dirty pages: orig.4036707, bitbased.67662, ratio.59.66
0 dirty pages: orig.3938085, bitbased.23634, ratio.166.63
0 dirty pages: orig.3968163, bitbased.23526, ratio.168.67
We didn't show the data for checking completely empty bitmap because it was too
fast and didn't wan't to get wrong impression.
> Note the issue with the cache accesses for set_dirty() is only
> applicable to tcg, since kvm always updates the dirty bitmap in a batch
> (well, I/O also updates the bitmap).
I understand.
I'm still concerned regarding the way of reseting the dirty bitmap.
I was thinking to reset them in a batch, but it seems difficult because of the
consistency with the tlb.
prev parent reply other threads:[~2010-03-16 13:41 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-16 10:53 [PATCH 0/6] qemu-kvm: Introduce bit-based phys_ram_dirty, and bit-based dirty page checker Yoshiaki Tamura
2010-03-16 10:53 ` [PATCH 1/6] qemu-kvm: Introduce bit-based phys_ram_dirty for VGA, CODE and MIGRATION Yoshiaki Tamura
2010-03-16 12:26 ` Avi Kivity
2010-03-16 13:01 ` Yoshiaki Tamura
2010-03-16 13:04 ` Avi Kivity
2010-03-16 10:53 ` [PATCH 2/6] qemu-kvm: Modify and introduce wrapper functions to access phys_ram_dirty Yoshiaki Tamura
2010-03-16 12:45 ` Avi Kivity
2010-03-16 13:17 ` Yoshiaki Tamura
2010-03-16 13:29 ` Avi Kivity
2010-03-16 13:49 ` Yoshiaki Tamura
2010-03-16 13:51 ` Anthony Liguori
2010-03-16 13:57 ` Avi Kivity
2010-03-16 14:50 ` Anthony Liguori
2010-03-16 20:10 ` [Qemu-devel] " Blue Swirl
2010-03-16 22:31 ` Richard Henderson
2010-03-17 0:05 ` [Qemu-devel] " Paul Brook
2010-03-17 4:07 ` Avi Kivity
2010-03-17 16:06 ` Paul Brook
2010-03-17 16:28 ` Avi Kivity
2010-03-16 13:35 ` Anthony Liguori
2010-03-16 22:50 ` Yoshiaki Tamura
2010-03-16 10:53 ` [PATCH 3/6] qemu-kvm: Replace direct phys_ram_dirty access with wrapper functions Yoshiaki Tamura
2010-03-16 10:53 ` [PATCH 4/6] qemu-kvm: Introduce cpu_physical_memory_get_dirty_range() Yoshiaki Tamura
2010-03-16 12:47 ` Avi Kivity
2010-03-16 10:53 ` [PATCH 5/6] qemu-kvm: Use cpu_physical_memory_set_dirty_range() to update phys_ram_dirty Yoshiaki Tamura
2010-03-16 10:53 ` [PATCH 6/6] qemu-kvm: Use cpu_physical_memory_get_dirty_range() to check multiple dirty pages Yoshiaki Tamura
2010-03-16 13:11 ` [PATCH 0/6] qemu-kvm: Introduce bit-based phys_ram_dirty, and bit-based dirty page checker Avi Kivity
2010-03-16 13:41 ` Yoshiaki Tamura [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4B9F8A81.3060005@lab.ntt.co.jp \
--to=tamura.yoshiaki@lab.ntt.co.jp \
--cc=anthony@codemonkey.ws \
--cc=avi@redhat.com \
--cc=kvm@vger.kernel.org \
--cc=ohmura.kei@lab.ntt.co.jp \
--cc=qemu-devel@nongnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox