Re: [Qemu-devel] [PATCH 0/3] block: introduce submit I/O at batch

[Ming Lei]

On Mon, Jun 30, 2014 at 8:32 PM, Paolo Bonzini <address@hidden> wrote:
> Il 30/06/2014 14:16, Ming Lei ha scritto:
>
>> I added the io queue into AioContext because the io queue can only
>> be used in the attached context(or thread), that said the io queue has to
>> be put into per context instance.
>
>
> It doesn't *have* to be per-thread.

For linux aio, because no thread pool is involved, I think
AioContext is still per thread if I understand correctly.

>
> It is certainly simplest if you make it per-io_context_t, but this in the
> current code means making it per-BlockDriverState and putting it in
> block/linux-aio.c.

OK, I will put it into qemu_laio_state first, but change to generic
block layer is still needed because at least plug/unplug interfaces
should be provided from block layer.

>
>
>> OK, I will not consider backing_hd case in v1, also the patchset will
>> not only improve dataplane, and other devices should benefit from
>> it too.
>>
>> These patches themselves should be simple, and most of code are
>> add-only, if bdrv_io_plug()/bdrv_io_unplug() isn't used, they are very
>> close
>> to noop.
>>
>> I just wrote a draft patch to apply the mechanism on virtio-scsi, and
>> the improvement is obvious.
>
>
> I certainly agree.  However, we have to also consider that we're close to
> releasing 2.1.


Thanks,
--
Ming Lei