Messages in this thread | | | From | Tim Connors <> | Subject | Re: [RFC v1] Tunable sched_mc_power_savings=n | Date | Sat, 28 Jun 2008 21:22:27 +1000 |
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Andi Kleen <andi@firstfloor.org> said on Fri, 27 Jun 2008 00:38:53 +0200: > Peter Zijlstra wrote: > > >> And your workload manager could just nice processes. It should probably > >> do that anyways to tell ondemand you don't need full frequency. > > > > Except that I want my nice 19 distcc processes to utilize as much cpu as > > possible, but just not bother any other stuff I might be doing... > > They already won't do that if you run ondemand and cpufreq. It won't > crank up the frequency for niced processes.
Shouldn't there be a powernice, just as there is an ionice and a nice? Just as you don't always want CPU priority and IO priority to be coupled, Peter has just demonstrated a very good case where you don't want power and CPU choices to be coupled. Whether the ondemand governor of CPUFreq counts a process as wanting the CPU to run at a higher speed, and these scheduler decisions should be controlled by powernice. By default, perhaps a high powernice should equal a high nice equal to a high ionice, but the user should be able to change this. The last thing you want is a distcc process taking up lots of time, burning more Joules because it runs 10 times longer with only half the power. It's not a nice choice between that and running at nice 0 where it interferes with the user's editing.
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