Hi Yuyang, On 08/10/14 01:50, Yuyang Du wrote: > Hi Morten, > > Sorry for late jumping in. > > The problem seems to be self-evident. But for the implementation to be > equally attractive it needs to account for every freq change for every task, > or anything less than that makes it less attractive. > > 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. > > For every task, this makes the updating of the entire queue in load tracking > more needed, so once again, ping maintainers for the rewrite patches, :) > > Thanks, > Yuyang > [...] -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
