Re: [Qemu-devel] [PATCH v3 9/9] coalesce adjacent iovecs

[Juan Quintela]

"Michael S. Tsirkin" <address@hidden> wrote:
> On Thu, Mar 21, 2013 at 06:27:42PM +0200, Orit Wasserman wrote:
>> On 03/21/2013 06:16 PM, Michael S. Tsirkin wrote:
>> > On Thu, Mar 21, 2013 at 06:05:40PM +0200, Orit Wasserman wrote:
>> >> This way we send one big buffer instead of many small ones
>> >>
>> >> Signed-off-by: Orit Wasserman <address@hidden>
>> > 
>> > Why does this happen BTW?
>> 
>> It happens in the last phase when we send the device state that
>> consists of a lot
>> bytes and int field that are written using qemu_put_byte/be16/...
>> 
>
> Confused  I thought device_state does not use _nocopy?
> My idea of using vmsplice relies exactly on this:
> we can not splice device state ...


As it is today, I am not sure that we can use vmsplice() because we
are sending:


<header>
<page>
<header>
<page>
<header>
<page>

We can optimize at some pount to write a bigger/different header and
sent a bunch of pages together, but just now we don't have that code.

Later, Juan.