diff options
| author | Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> | 2016-10-25 13:20:41 -0700 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2016-11-01 06:04:06 +0100 |
| commit | 5879f877398a2a5e5006c6e16a4288e9d4c308a1 (patch) | |
| tree | 28bf92f4d5ecca835c031e05e731f303ef988ef7 /drivers/cpufreq | |
| parent | eae48f046ffa117afb782cd9b3ae5469df0042e2 (diff) | |
cpufreq: intel_pstate: Reduce impact due to rounding error
When policy->max and policy->min are same, in some cases they don't
result in the same frequency cap. The max_policy_pct is rounded up but
not min_perf_pct. So even when they are same, results in different
percentage or maximum and minimum.
Since minimum is a conservative value for power, a lower value without
rounding is better in most of the cases, unless user wants
policy->max = policy->min.
This change uses use the same policy percentage when policy->max and
policy->min are same.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq')
| -rw-r--r-- | drivers/cpufreq/intel_pstate.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index b6e9b49bf151..8e7390bb2175 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -1543,11 +1543,17 @@ static void intel_pstate_set_performance_limits(struct perf_limits *limits) static void intel_pstate_update_perf_limits(struct cpufreq_policy *policy, struct perf_limits *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 = DIV_ROUND_UP(policy->max * 100, policy->cpuinfo.max_freq); limits->max_policy_pct = clamp_t(int, limits->max_policy_pct, 0, 100); + if (policy->max == policy->min) { + limits->min_policy_pct = limits->max_policy_pct; + } else { + limits->min_policy_pct = (policy->min * 100) / + policy->cpuinfo.max_freq; + limits->min_policy_pct = clamp_t(int, limits->min_policy_pct, + 0, 100); + } /* Normalize user input to [min_policy_pct, max_policy_pct] */ limits->min_perf_pct = max(limits->min_policy_pct, |