Re: [Qemu-devel] question about performance of dataplane

[Stefan Hajnoczi <stefanha@gmail.com>]

On Sun, Apr 07, 2013 at 09:05:47AM -0500, Anthony Liguori wrote:
> Zhangleiqiang <zhangleiqiang@huawei.com> writes:
> 
> > Hi, Stefan：
> >
> > 	I have done some testing to compare the performance of dataplane and non-dataplane.  But the result did not meet my expectations, the performance of disk with dataplane enabled did not have advantage over non-dataplane. 
> >
> > 	The following  contains the  environment info and testing results.  Does my testing method or testing environment have something wrong ?  Could you give me some advice?  I can provide more information if need.
> >
> >
> > 1. Environment:
> > 	a). Qemu 1.4 master branch
> > 	b). kernel:  3.5.0-2.fc17.x86_64
> >          c). virtual disks location:  the same local SATA harddisk
> > 	with ext4 fs
> 
> I doubt you'll see any performance difference with a single SATA drive.
> There's no real parallelism possible as you have exactly one spindle
> available.

Sorry for the delay, catching up on emails after my Easter vacation.

I agree with Anthony here.  It seems your benchmark configuration is
bottlenecked below the point where data plane makes a difference.

Stefan