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Re: [Xen-devel] Poor performance with Linux 3.x as dom0

On 03.05.2012 12:51, Ian Campbell wrote:
On Thu, 2012-05-03 at 11:43 +0100, Andreas Kinzler wrote:
On 02.05.2012 15:31, Ian Campbell wrote:
Did you happen to also compare 3.2.12 and running these
workloads natively?
Yes, I tested against 2.6.32.x. Differences exist, but are minor.

Good to know, thanks for testing

The other potential Xen perf thing which just occurred to to me is the
ACPI power management stuff which the xen-acpi-processor patches in
3.4-rcN are fixing. These are necessary to enable things like turbo mode
so have a pretty large perf impact.

Are you able to try the latest 3.4-rc kernel?

Yes, meanwhile I tried 3.4-rc7. There is some improvement but still a good bit away from 2.6.34 xenified:

time emerge apache:

                3.2.12-dom0     3.3.4-dom0 (w. patch)   3.4.0-rc7
        real    1m0.560s        0m59.971s (0m58.029s)   0m55.000s       
        user    0m40.939s       0m40.619s (0m40.291s)   0m37.846s       
        sys     0m18.865s       0m18.305s (0m16.837s)   0m16.041s       

time make -j4 (3.2.12 linux compile):

                3.2.12-dom0     3.3.4-dom0 (w. patch)   3.4.0-rc7
        real    5m8.793s        5m4.888s  (5m1.408s)    4m48.839s       
        user    8m1.746s        7m59.726s (7m57.534s)   7m40.129s       
        sys     1m39.010s       1m32.994s (1m29.518s)   1m20.993s       

Regards Andreas

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