Messages in this thread | ![/](/images/icornerl.gif) | | Date | Sat, 1 Dec 2007 08:30:02 -0800 | From | Arjan van de Ven <> | Subject | Re: + restore-missing-sysfs-max_cstate-attr.patch added to -mm tree |
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On Sat, 1 Dec 2007 02:17:40 -0800 Andrew Morton <akpm@linux-foundation.org> wrote:
> On Fri, 30 Nov 2007 22:14:08 -0500 Mark Lord <lkml@rtr.ca> wrote: > > > > latency. If your app cant take any latency, you should set > > > those... and the side effect is that the kernel will not do > > > long-latency C-states or P-state transitions.. > > .. > > > > I don't mind the cpufreq changing (actually, I want it to drop in > > cpugfreq to save power and keep the fan off), but the C-states just > > kill this app. > > semi-OT: I was finding that disabling cpufreq altogether on the Vaio > speeds up `quilt push 1000' by a lot - around 30% iirc.
I assume this is using the ondemand governor and not userspace? (some older distros mistakingly used "userspace" and yes, that will suck)
# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor ondemand
(to make it easily cut-n-pastable to check)
> > There do seem to be some unsophisticated decisions in there and we're > losing quite a bit of performance as a result.
if you can give a simple recipe for one of these, we can add it to our workload testsuite that at least some of us use every time we change either the C states or the cpufreq stuff....
(and yes we want to improve things)
-- If you want to reach me at my work email, use arjan@linux.intel.com For development, discussion and tips for power savings, visit http://www.lesswatts.org
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