Re: [Qemu-devel] Migration ToDo list

[Paolo Bonzini]

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.

Paolo