On Mon, 2008-02-25 at 08:37 -0800, Arjan van de Ven wrote:

> 
> I'll CC Tim who might be able to give you some other suggestions wrt specpower
> 

Martin,

Some of the steps we have found to help include:

0. Employ large pages in Linux and in your java option.

1. Employ a tickless kernel, probably a kernel close to 2.6.24.

2. Turn on the ondemand governor (set
/sys/devices/system/devices/system/cpu/cpu*/cpufreq/scaling_governor to
ondemand).

3. Trun on the menu idle governor (set
/sys/devices/system/cpu/cpuidle_governor_ro to menu)

4. Turning on the power aware scheduler  (set
/sys/devices/system/cpu/sched_mc_power_savings to 1)

5. Use a larger sampling (like 1000000) versus the default value of 2000
in /sys/devices/system/cpu/cpu*/cpufreq/ondemand/sampling_rate.  For
SPECpower workload, the load level is very steady, so it does not pay to
shift gear to a high cpu frequency too quickly.

6. Employ idle microstate accounting (not yet available in distribution
kernel) 

Also check the BIOS setting to make sure things like speedstep and fan
speed and accoustic is set properly.

Tim


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