Re: [Qemu-devel] [PATCH 2/3] Improve xen_disk response latency

[Anthony PERARD]

On Fri, Nov 02, 2018 at 10:01:04AM +0000, Tim Smith wrote:
> If the I/O ring is full, the guest cannot send any more requests
> until some responses are sent. Only sending all available responses
> just before checking for new work does not leave much time for the
> guest to supply new work, so this will cause stalls if the ring gets
> full. Also, not completing reads as soon as possible adds latency
> to the guest.
> 
> To alleviate that, complete IO requests as soon as they come back.
> blk_send_response() already returns a value indicating whether
> a notify should be sent, which is all the batching we need.
> 
> Signed-off-by: Tim Smith <address@hidden>

Acked-by: Anthony PERARD <address@hidden>

-- 
Anthony PERARD