Messages in this thread | | | Subject | Re: [PATCH] sched: Initialize rq->age_stamp on processor start | From | Mike Galbraith <> | Date | Tue, 18 Mar 2014 10:25:43 +0100 |
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On Tue, 2014-03-18 at 09:56 +0100, Peter Zijlstra wrote: > On Tue, Mar 18, 2014 at 05:06:26AM +0100, Mike Galbraith wrote:
> > > +static void __cpuinit set_cpu_rq_start_time(void) > > > +{ > > > + int cpu = smp_processor_id(); > > > + struct rq *rq = cpu_rq(cpu); > > > + rq->age_stamp = sched_clock_cpu(cpu); > > > +} > > > > rq->age_stamp must lag rq->clock. See scale_rt_power(), and what > > happens when it munches magic timewarp mushrooms. > > > > > + > > > static int sched_cpu_active(struct notifier_block *nfb, > > > unsigned long action, void *hcpu) > > > { > > > switch (action & ~CPU_TASKS_FROZEN) { > > > case CPU_STARTING: > > > + set_cpu_rq_start_time(); > > > + /* fall through */ > > > case CPU_DOWN_FAILED: > > > set_cpu_active((long)hcpu, true); > > > return NOTIFY_OK; > > > @@ -6922,6 +6931,7 @@ void __init sched_init(void) > > > init_sched_fair_class(); > > > > > > scheduler_running = 1; > > > + set_cpu_rq_start_time(); > > I would put it one line up; that scheduler_running=1 is the last thing > we should do.
And set clock and age, dazed scale_rt_power() is butt ugly.
-Mike
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