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Re: [Qemu-devel] [PATCHv3 9/9] migration: use XBZRLE only after bulk sta
From: |
Eric Blake |
Subject: |
Re: [Qemu-devel] [PATCHv3 9/9] migration: use XBZRLE only after bulk stage |
Date: |
Thu, 21 Mar 2013 13:31:18 -0600 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130311 Thunderbird/17.0.4 |
On 03/21/2013 09:57 AM, Peter Lieven wrote:
> at the beginning of migration all pages are marked dirty and
> in the first round a bulk migration of all pages is performed.
>
> currently all these pages are copied to the page cache regardless
> if there are frequently updated or not. this doesn't make sense
s/if there/of whether they/
> since most of these pages are never transferred again.
>
> this patch changes the XBZRLE transfer to only be used after
> the bulk stage has been completed. that means a page is added
> to the page cache the second time it is transferred and XBZRLE
> can benefit from the third time of transfer.
>
> since the page cache is likely smaller than the number of pages
> its also likely that in the second round the page is missing in the
s/its/it's/
> cache due to collisions in the bulk phase.
>
> on the other hand a lot of unnecessary mallocs, memdups and frees
> are saved.
>
...
> Signed-off-by: Peter Lieven <address@hidden>
> ---
> arch_init.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Prior review still stands (touching up typos in a commit message
generally does not invalidate carrying forward a reviewed-by comment).
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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- [Qemu-devel] [PATCHv3 8/9] migration: do not search dirty pages in bulk stage, (continued)
- [Qemu-devel] [PATCHv3 8/9] migration: do not search dirty pages in bulk stage, Peter Lieven, 2013/03/21
- [Qemu-devel] [PATCHv3 7/9] migration: do not sent zero pages in bulk stage, Peter Lieven, 2013/03/21
- [Qemu-devel] [PATCHv3 2/9] cutils: add a function to find non-zero content in a buffer, Peter Lieven, 2013/03/21
- [Qemu-devel] [PATCHv3 9/9] migration: use XBZRLE only after bulk stage, Peter Lieven, 2013/03/21
- Re: [Qemu-devel] [PATCHv3 9/9] migration: use XBZRLE only after bulk stage,
Eric Blake <=
- [Qemu-devel] [PATCHv3 5/9] migration: search for zero instead of dup pages, Peter Lieven, 2013/03/21
- [Qemu-devel] [PATCHv3 6/9] migration: add an indicator for bulk state of ram migration, Peter Lieven, 2013/03/21
- [Qemu-devel] [PATCHv3 3/9] buffer_is_zero: use vector optimizations if possible, Peter Lieven, 2013/03/21