| Message ID | 1448063277-12446-2-git-send-email-prarit@redhat.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Rafael Wysocki |
| Headers | show |
On Fri, 2015-11-20 at 18:47 -0500, Prarit Bhargava wrote: > I have a Intel (6,63) processor with a "marketing" frequency (from > /proc/cpuinfo) of 2100MHz, and a max turbo frequency of 2600MHz. I > can execute > > cpupower frequency-set -g powersave --min 1200MHz --max 2100MHz > > and the max_freq_pct is set to 80. When adding load to the system I noticed > that the cpu frequency only reached 2000MHZ and not 2100MHz as expected. > > This is because limits->max_policy_pct is calculated as 2100 * 100 /2600 = 80.7 > and is rounded down to 80 when it should be rounded up to 81. This patch > adds a DIV_ROUND_UP() which will return the correct value. > > Cc: Srinivas Pandruvada <srinivas.pandruvada@intel.com> > Cc: Len Brown <len.brown@intel.com> > Cc: Alexandra Yates <alexandra.yates@intel.com> > Cc: Kristen Carlson Accardi <kristen@linux.intel.com> > Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> > Cc: Viresh Kumar <viresh.kumar@linaro.org> > Cc: linux-pm@vger.kernel.org > Signed-off-by: Prarit Bhargava <prarit@redhat.com> Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> > --- > drivers/cpufreq/intel_pstate.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c > index 001a532..eb75053 100644 > --- a/drivers/cpufreq/intel_pstate.c > +++ b/drivers/cpufreq/intel_pstate.c > @@ -1108,7 +1108,8 @@ static int intel_pstate_set_policy(struct cpufreq_policy *policy) > limits = &powersave_limits; > limits->min_policy_pct = (policy->min * 100) / policy->cpuinfo.max_freq; > limits->min_policy_pct = clamp_t(int, limits->min_policy_pct, 0 , 100); > - limits->max_policy_pct = (policy->max * 100) / policy->cpuinfo.max_freq; > + limits->max_policy_pct = DIV_ROUND_UP(policy->max * 100, > + policy->cpuinfo.max_freq); > limits->max_policy_pct = clamp_t(int, limits->max_policy_pct, 0 , 100); > > /* Normalize user input to [min_policy_pct, max_policy_pct] */
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 001a532..eb75053 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -1108,7 +1108,8 @@ static int intel_pstate_set_policy(struct cpufreq_policy *policy) limits = &powersave_limits; limits->min_policy_pct = (policy->min * 100) / policy->cpuinfo.max_freq; limits->min_policy_pct = clamp_t(int, limits->min_policy_pct, 0 , 100); - limits->max_policy_pct = (policy->max * 100) / policy->cpuinfo.max_freq; + limits->max_policy_pct = DIV_ROUND_UP(policy->max * 100, + policy->cpuinfo.max_freq); limits->max_policy_pct = clamp_t(int, limits->max_policy_pct, 0 , 100); /* Normalize user input to [min_policy_pct, max_policy_pct] */
I have a Intel (6,63) processor with a "marketing" frequency (from /proc/cpuinfo) of 2100MHz, and a max turbo frequency of 2600MHz. I can execute cpupower frequency-set -g powersave --min 1200MHz --max 2100MHz and the max_freq_pct is set to 80. When adding load to the system I noticed that the cpu frequency only reached 2000MHZ and not 2100MHz as expected. This is because limits->max_policy_pct is calculated as 2100 * 100 /2600 = 80.7 and is rounded down to 80 when it should be rounded up to 81. This patch adds a DIV_ROUND_UP() which will return the correct value. Cc: Srinivas Pandruvada <srinivas.pandruvada@intel.com> Cc: Len Brown <len.brown@intel.com> Cc: Alexandra Yates <alexandra.yates@intel.com> Cc: Kristen Carlson Accardi <kristen@linux.intel.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: linux-pm@vger.kernel.org Signed-off-by: Prarit Bhargava <prarit@redhat.com> --- drivers/cpufreq/intel_pstate.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)