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Re: [Qemu-devel] [PATCH v2 1/5] linux-aio: queue requests that cannot be
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH v2 1/5] linux-aio: queue requests that cannot be submitted |
Date: |
Tue, 16 Dec 2014 12:07:27 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Am 11.12.2014 um 14:52 hat Paolo Bonzini geschrieben:
> Keep a queue of requests that were not submitted; pass them to
> the kernel when a completion is reported, unless the queue is
> plugged.
>
> The array of iocbs is rebuilt every time from scratch. This
> avoids keeping the iocbs array and list synchronized.
>
> Signed-off-by: Paolo Bonzini <address@hidden>
Just found out that in qemu-img bench, this patch seems to cost about
5-8% for me.
An optimisation for the unplugged case would probably be easy, but that
would be cheating, as the devices that we're really interested in always
plug the queue (perhaps I should extend qemu-img bench to do that
optionally, too).
Anything clever that we can do about this? Or will we just have to live
with the fact that sending a single request is now slower than it used
to be before bdrv_plug?
Kevin
- [Qemu-devel] [PATCH v2 0/5] linux-aio: rewrite and simplify queuing code, Paolo Bonzini, 2014/12/11
- [Qemu-devel] [PATCH v2 1/5] linux-aio: queue requests that cannot be submitted, Paolo Bonzini, 2014/12/11
- Re: [Qemu-devel] [PATCH v2 1/5] linux-aio: queue requests that cannot be submitted,
Kevin Wolf <=
- Re: [Qemu-devel] [PATCH v2 1/5] linux-aio: queue requests that cannot be submitted, Paolo Bonzini, 2014/12/16
- Re: [Qemu-devel] [PATCH v2 1/5] linux-aio: queue requests that cannot be submitted, Kevin Wolf, 2014/12/16
- Re: [Qemu-devel] [PATCH v2 1/5] linux-aio: queue requests that cannot be submitted, Paolo Bonzini, 2014/12/16
- Re: [Qemu-devel] [PATCH v2 1/5] linux-aio: queue requests that cannot be submitted, Paolo Bonzini, 2014/12/16
- Re: [Qemu-devel] [PATCH v2 1/5] linux-aio: queue requests that cannot be submitted, Paolo Bonzini, 2014/12/17
- Re: [Qemu-devel] [PATCH v2 1/5] linux-aio: queue requests that cannot be submitted, Paolo Bonzini, 2014/12/17
[Qemu-devel] [PATCH v2 2/5] linux-aio: track whether the queue is blocked, Paolo Bonzini, 2014/12/11
[Qemu-devel] [PATCH v2 4/5] linux-aio: drop return code from laio_io_unplug and ioq_submit, Paolo Bonzini, 2014/12/11
[Qemu-devel] [PATCH v2 5/5] linux-aio: simplify removal of completed iocbs from the list, Paolo Bonzini, 2014/12/11
[Qemu-devel] [PATCH v2 3/5] linux-aio: rename LaioQueue idx field to "n", Paolo Bonzini, 2014/12/11