Re: Poor performance with Linux 3.x as dom0

[Andreas Kinzler <ml-xen-devel@hfp.de>]

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 2.6.34.10 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	2.6.34.10-dom0
	real    1m0.560s	0m59.971s (0m58.029s)	0m55.000s	0m47.689s
	user    0m40.939s	0m40.619s (0m40.291s)	0m37.846s	0m41.355s
	sys     0m18.865s	0m18.305s (0m16.837s)	0m16.041s	0m11.441s

time make -j4 (3.2.12 linux compile):

		3.2.12-dom0	3.3.4-dom0 (w. patch)	3.4.0-rc7	2.6.34.10-dom0
	real    5m8.793s	5m4.888s  (5m1.408s)	4m48.839s	4m20.576s
	user    8m1.746s	7m59.726s (7m57.534s)	7m40.129s	7m10.375s
	sys     1m39.010s	1m32.994s (1m29.518s)	1m20.993s	0m56.304s

Regards Andreas