On 02/09/2011 06:35 PM, Aurelien Jarno wrote:
On Tue, Feb 08, 2011 at 04:08:28PM +0100, Aurelien Jarno wrote:
Aurelien Jarno a écrit :
Paolo Bonzini a écrit :
On 02/08/2011 12:15 PM, Aurelien Jarno wrote:
however
it should not be done ignoring all the*current* drawbacks of the
iothread mode. We know them (at least for some of them), so let's try to
solve them.
Let's also enumerate them.
From what I know:
- performance regression in TCG mode
I setup an x86_64 guest on an x86_64 host (Intel Xeon E5345). Nothing
was running except the standard daemons and the CPU governor was set to
"performance" on all CPU. I then compared the network performance using
netperf in default mode, through a tap interface and a virtio nic. I got
the following results (quite reproducible, std below 0.5):
- without IO thread: 107.36 MB/s
- with IO thread: 89.93 MB/s
And the same test on the code from september 2009:
- without IO thread: 141.8 MB/s
virtio-net is super finicky regarding mitigation strategies and their
relationship to the I/O thread. Different benchmarks will behave
differently. virtio-blk is probably a better device to test as you'll
get much more consistent results across different type of I/O patterns.
Regards,
Anthony Liguori
