Messages in this thread |  | | Date | Fri, 10 Oct 2014 11:16:21 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 1/7] sched: Introduce scale-invariant load tracking |
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On Wed, Oct 08, 2014 at 01:54:58PM +0100, Dietmar Eggemann wrote:
> > But this should be very hard. Intel Architecture has limitation to capture all > > the freq changes in software and also the intel_pstate should have no > > notification. > > We encountered this missing notification for current frequency with > Intel systems (e.g. i5-3320M) using the intel_pstate driver while > testing this patch-set. The arch_scale_set_curr_freq call in > __cpufreq_notify_transition [[PATCH 2/7] cpufreq: Architecture specific > callback for frequency changes] will not work on such a system. > > In our internal testing, we placed arch_scale_set_curr_freq(cpu->cpu, > sample->freq) into intel_pstate_timer_func [intel_pstate.c] to get the > current frequency for a cpu. > > The arch_scale_set_max_freq call in cpufreq_set_policy > [drivers/cpufreq/cpufreq.c] still works although the driver exposes the > max turbo pstate and not the max pstate. That's an additional problem > because we don't want to use turbo states for frequency scaling.
Right, so when we pull the policy part into the scheduler, intel_pstate will revert to just another driver without such logic and things should just work.
But yes, currently it also implements policy, that needs to go away.
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