On Thursday, October 16, 2014 01:16:51 AM Pali Rohár wrote: > Code which changes policy to powersave changes also max_policy_pct based on > max_freq. Code which change max_perf_pct has upper limit base on value > max_policy_pct. When policy is changing from powersave back to performance > then max_policy_pct is not changed. Which means that changing max_perf_pct is > not possible to high values if max_freq was too low in powersave policy.
Dirk, what do you think? > Test case: > > $ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq > 800000 > $ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq > 3300000 > $ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor > performance > $ cat /sys/devices/system/cpu/intel_pstate/max_perf_pct > 100 > > $ echo powersave > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor > $ echo 800000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq > $ echo 20 > /sys/devices/system/cpu/intel_pstate/max_perf_pct > > $ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor > powersave > $ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq > 800000 > $ cat /sys/devices/system/cpu/intel_pstate/max_perf_pct > 20 > > $ echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor > $ echo 3300000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq > $ echo 100 > /sys/devices/system/cpu/intel_pstate/max_perf_pct > > $ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor > performance > $ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq > 3300000 > $ cat /sys/devices/system/cpu/intel_pstate/max_perf_pct > 24 > > And now intel_pstate driver allows to set maximal value for max_perf_pct based > on max_policy_pct which is 24 for previous powersave max_freq 800000. > > This patch will set default value for max_policy_pct when setting policy to > performance so it will allow to set also max value for max_perf_pct. > > Signed-off-by: Pali Rohár <[email protected]> > Cc: [email protected] > --- > drivers/cpufreq/intel_pstate.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c > index 0668b38..7547ab5 100644 > --- a/drivers/cpufreq/intel_pstate.c > +++ b/drivers/cpufreq/intel_pstate.c > @@ -714,6 +714,7 @@ static int intel_pstate_set_policy(struct cpufreq_policy > *policy) > if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) { > limits.min_perf_pct = 100; > limits.min_perf = int_tofp(1); > + limits.max_policy_pct = 100; > limits.max_perf_pct = 100; > limits.max_perf = int_tofp(1); > limits.no_turbo = limits.turbo_disabled; > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
