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Re: [Qemu-devel] Migration ToDo list
From: |
Isaku Yamahata |
Subject: |
Re: [Qemu-devel] Migration ToDo list |
Date: |
Wed, 14 Nov 2012 11:14:22 +0900 |
User-agent: |
Mutt/1.5.19 (2009-01-05) |
On Tue, Nov 13, 2012 at 06:16:30PM +0100, Paolo Bonzini wrote:
> Il 13/11/2012 18:09, Orit Wasserman ha scritto:
> >> >
> >>> >> b) do scatter/gather of the pages?
> > I would prefer to postpone changing the protocol and start with using iov
> > (writev)
> > for sending the pages (still sending header and than the page). Later we
> > can
> > move to scatter/gather I'm not sure of how large the performance gain will
> > be.
> >> >
> >> > c) Remove compression of non-zero repetitive pages.
> > +1
> > we can look of identify the zero pages without calling is_dup_page which
> > looks
> > expensive.
>
> Identifying ballooned zero pages is useful, because those cause the
> clear_page calls in the kernel even in a guest that has been running for
> a while.
>
> But a generic solution doesn't really matter, because is_dup_page and
> clear_page shouldn't really be in the profile in practice, except in
> microbenchmarks.
I guess mincore(2) can be used as easy way to detect non-mapped page.
This is just implementation detail anyway.
--
yamahata
Re: [Qemu-devel] Migration ToDo list, Orit Wasserman, 2012/11/13
Re: [Qemu-devel] Migration ToDo list, Chegu Vinod, 2012/11/13