[Beowulf] Powersave on Beowulf nodes

[Eoin McHugh]

On Sun, Jun 15, 2008 at 04:26:24AM +0400, Mikhail Kuzminsky wrote:
> We have many jobs in SGE at every time moment, and underload situation 
> (where it's reasonable to decrease CPUs frequency) is not the our 
> danger :-)  So I'm thinking about simple stopping of all the 
> corresponding daemons.

Hi Mikhail,

There's not much point to running a powersave daemon. Even if a job is
not CPU bound you'll find that lower power states will probably have a
negative effect on your interconnect performance too.

I don't run a daemon but I use the Torque prologue and epilogue to set
the max and min power states using the /proc cpufreq interface before 
and after jobs. This results in a power saving when a queued jobs are 
waiting for additional nodes to free up. It's a measurably large 
difference when the system is being drained prior to a downtime. Our 
nodes are never shared beteen jobs making this easy to implement.

Regards,

-- 
Eoin McHugh
ICHEC Systems