qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

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



reply via email to

[Prev in Thread] Current Thread [Next in Thread]