Messages in this thread | | | From | Namhyung Kim <> | Subject | Re: [RFC 2/2] sched/fair: prefer a CPU in the "lowest" idle state | Date | Thu, 31 Jan 2013 15:58:38 +0900 |
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On Thu, 31 Jan 2013 14:39:20 +0800, Michael Wang wrote: > On 01/31/2013 01:16 PM, Namhyung Kim wrote: >> Anyway, I have an idea with this in mind. It's like adding a new "idle >> load" to each idle cpu rather than special casing the idle cpus like >> above. IOW an idle cpu will get very small load weight depends on how >> deep it's slept so that it can be compared to other cpus in a same way >> but we can find prefered (lowest load) cpu among the idle cpus. >> >> The simple way I can think of is adding idle_level to a rq load in >> weighted_cpuload(): >> >> static unsigned long weighted_cpuload(const int cpu) >> { >> return cpu_rq(cpu)->load.weight + cpuidle_get_state(cpu); >> } > > Hmm... then we don't need changes in find_idlest_cpu(), just compare the > load as before, but it works only when the appendix state value is > smaller than the lowest load of one task, which is 15 currently, I'm not > sure whether we have the promise...
You said about a nice 19 process, right? But I found that SCHED_IDLE task will have weight of 3. :(
#define WEIGHT_IDLEPRIO 3
But AFAIK the number of states in cpuidle is usually less than 10 so maybe we can change the weight then, but there's no promise...
Thanks, Namhyung
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