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Date: Mon, 7 Feb 2011 21:44:07 +0100
From: Aurelien Jarno <aurelien@aurel32.net>
Subject: Re: [Qemu-devel] Re: [PATCH 2/7] Enable I/O thread and VNC threads
	by default
Message-ID: <20110207204407.GA16429@hall.aurel32.net>
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To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>, Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>, qemu-devel@nongnu.org, Anthony Liguori <aliguori@linux.vnet.ibm.com>, Paulo Bonzini <pbonzini@redhat.com>, Paul Brook <paul@codesourcery.com>, Arun Bharadwaj <arun@linux.vnet.ibm.com>, "Edgar E. Iglesias" <edgar.iglesias@gmail.com>

On Mon, Feb 07, 2011 at 02:03:50PM -0200, Marcelo Tosatti wrote:
> On Mon, Feb 07, 2011 at 08:12:55AM -0200, Marcelo Tosatti wrote:
> > > > One more thing I didn't mention on the email-thread or on IRC is
> > > > that last time I checked, qemu with io-thread was performing
> > > > significantly slower than non io-thread builds. That was with
> > > > TCG emulation (not kvm). Somewhere between 5 - 10% slower, IIRC.
> > 
> > Can you recall what was the test ?
> > 

It's also something I've seen using network transfer in guest. IIRC the
biggest slowdown was using the smc91c111 card under qemu-system-arm
where it was about 20% slower. Other cards on other architectures (I
remember testing powerpc, mips and sh4) are more in the 5 to 10 % area.

-- 
Aurelien Jarno	                        GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net