From: Martin Mailand <martin@tuxadero.com>
To: Dongsu Park <dongsu.park@profitbricks.com>
Cc: stefanha@gmail.com, qemu-devel@nongnu.org, kvm@vger.kernel.org
Subject: Re: [Qemu-devel] virtio-blk performance regression and qemu-kvm
Date: Mon, 05 Mar 2012 17:13:20 +0100 [thread overview]
Message-ID: <4F54E620.8060400@tuxadero.com> (raw)
In-Reply-To: <20120210143639.GA17883@gmail.com>
Am 10.02.2012 15:36, schrieb Dongsu Park:
> Recently I observed performance regression regarding virtio-blk,
> especially different IO bandwidths between qemu-kvm 0.14.1 and 1.0.
> So I want to share the benchmark results, and ask you what the reason
> would be.
Hi,
I think I found the problem, there is no regression in the code.
I think the problem is, that qmeu-kvm with the IO-Thread enabled doesn't
produce enough cpu load to get the core to a higher cpu frequency,
because the load is distributed to two threads.
If I change the cpu governor to "performance" the result from the master
branch is better than from the v0.14.1 branch.
I get the same results on a serversystem without powermanagment activated.
@Dongsu Could you confirm those findings?
1. Test on i7 Laptop with Cpu governor "ondemand".
v0.14.1
bw=63492KB/s iops=15873
bw=63221KB/s iops=15805
v1.0
bw=36696KB/s iops=9173
bw=37404KB/s iops=9350
master
bw=36396KB/s iops=9099
bw=34182KB/s iops=8545
Change the Cpu governor to "performance"
master
bw=81756KB/s iops=20393
bw=81453KB/s iops=20257
2. Test on AMD Istanbul without powermanagement activated.
v0.14.1
bw=53167KB/s iops=13291
bw=61386KB/s iops=15346
v1.0
bw=43599KB/s iops=10899
bw=46288KB/s iops=11572
master
bw=60678KB/s iops=15169
bw=62733KB/s iops=15683
-martin
next prev parent reply other threads:[~2012-03-05 16:13 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-10 14:36 [Qemu-devel] virtio-blk performance regression and qemu-kvm Dongsu Park
2012-02-12 23:55 ` Rusty Russell
2012-02-21 16:45 ` Dongsu Park
2012-02-21 22:16 ` Rusty Russell
2012-02-13 11:57 ` Stefan Hajnoczi
2012-02-21 15:57 ` Dongsu Park
2012-02-21 17:27 ` Stefan Hajnoczi
2012-02-22 16:48 ` Dongsu Park
2012-02-22 19:53 ` Stefan Hajnoczi
2012-02-28 16:39 ` Martin Mailand
2012-02-28 17:05 ` Stefan Hajnoczi
2012-02-28 17:15 ` Martin Mailand
2012-02-29 8:38 ` Stefan Hajnoczi
2012-02-29 13:12 ` Martin Mailand
2012-02-29 13:44 ` Stefan Hajnoczi
2012-02-29 13:52 ` Stefan Hajnoczi
2012-03-05 16:13 ` Martin Mailand [this message]
2012-03-05 16:35 ` Stefan Hajnoczi
2012-03-05 16:44 ` Martin Mailand
2012-03-06 12:59 ` Stefan Hajnoczi
2012-03-06 22:07 ` Reeted
2012-03-07 8:04 ` Stefan Hajnoczi
2012-03-07 14:21 ` Reeted
2012-03-07 14:33 ` Stefan Hajnoczi
2012-03-07 10:39 ` Martin Mailand
2012-03-07 11:21 ` Paolo Bonzini
2012-03-06 14:32 ` Dongsu Park
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