diff options
| author | Prarit Bhargava <prarit@redhat.com> | 2015-11-20 18:47:56 -0500 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2015-11-23 23:14:10 +0100 |
| commit | 8478f53946f01b8365a206ac58a2640e3e408fb2 (patch) | |
| tree | 48bc2f7b6e6cda141b7685d89f3750c669c62ae0 | |
| parent | f344dae0fe9f88d3c7ec45f2d7bba84d6ce1ac00 (diff) | |
| download | linux-8478f53946f01b8365a206ac58a2640e3e408fb2.tar.bz2 | |
cpufreq: intel_pstate: Fix limits->max_policy_pct rounding error
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.
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
| -rw-r--r-- | drivers/cpufreq/intel_pstate.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 001a532e342e..eb75053f1371 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] */ |