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authorDirk Brandewie <dirk.j.brandewie@intel.com>2013-05-07 08:20:25 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-05-19 11:38:42 -0700
commit5aacc8bcf0b23e20cbb205ac6fdc3ce797e1cae2 (patch)
tree28970329151a4f377e6c7f22b03939d5f2d9c8b9
parent60b19b611510f4d55787e5143ba085baab106e49 (diff)
downloadvexpress-lsk-5aacc8bcf0b23e20cbb205ac6fdc3ce797e1cae2.tar.gz
cpufreq / intel_pstate: remove idle time and duration from sample and calculations
commit 1abc4b20b85b42e8573957e54b193385cf48b0d6 upstream. Idle time is taken into account in the APERF/MPERF ratio calculation there is no reason for the driver to track it seperately. This reduces the work in the driver and makes the code more readable. Removal of the tracking of sample duration removes the possibility of the divide by zero exception when the duration is sub 1us References: https://bugzilla.kernel.org/show_bug.cgi?id=56691 Reported-by: Mike Lothian <mike@fireburn.co.uk> Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/cpufreq/intel_pstate.c45
1 files changed, 8 insertions, 37 deletions
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 6133ef5cf67..e4786423f3f 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -48,12 +48,7 @@ static inline int32_t div_fp(int32_t x, int32_t y)
}
struct sample {
- ktime_t start_time;
- ktime_t end_time;
int core_pct_busy;
- int pstate_pct_busy;
- u64 duration_us;
- u64 idletime_us;
u64 aperf;
u64 mperf;
int freq;
@@ -91,8 +86,6 @@ struct cpudata {
int min_pstate_count;
int idle_mode;
- ktime_t prev_sample;
- u64 prev_idle_time_us;
u64 prev_aperf;
u64 prev_mperf;
int sample_ptr;
@@ -450,48 +443,26 @@ static inline void intel_pstate_calc_busy(struct cpudata *cpu,
struct sample *sample)
{
u64 core_pct;
- sample->pstate_pct_busy = 100 - div64_u64(
- sample->idletime_us * 100,
- sample->duration_us);
core_pct = div64_u64(sample->aperf * 100, sample->mperf);
sample->freq = cpu->pstate.max_pstate * core_pct * 1000;
- sample->core_pct_busy = div_s64((sample->pstate_pct_busy * core_pct),
- 100);
+ sample->core_pct_busy = core_pct;
}
static inline void intel_pstate_sample(struct cpudata *cpu)
{
- ktime_t now;
- u64 idle_time_us;
u64 aperf, mperf;
- now = ktime_get();
- idle_time_us = get_cpu_idle_time_us(cpu->cpu, NULL);
-
rdmsrl(MSR_IA32_APERF, aperf);
rdmsrl(MSR_IA32_MPERF, mperf);
- /* for the first sample, don't actually record a sample, just
- * set the baseline */
- if (cpu->prev_idle_time_us > 0) {
- cpu->sample_ptr = (cpu->sample_ptr + 1) % SAMPLE_COUNT;
- cpu->samples[cpu->sample_ptr].start_time = cpu->prev_sample;
- cpu->samples[cpu->sample_ptr].end_time = now;
- cpu->samples[cpu->sample_ptr].duration_us =
- ktime_us_delta(now, cpu->prev_sample);
- cpu->samples[cpu->sample_ptr].idletime_us =
- idle_time_us - cpu->prev_idle_time_us;
-
- cpu->samples[cpu->sample_ptr].aperf = aperf;
- cpu->samples[cpu->sample_ptr].mperf = mperf;
- cpu->samples[cpu->sample_ptr].aperf -= cpu->prev_aperf;
- cpu->samples[cpu->sample_ptr].mperf -= cpu->prev_mperf;
-
- intel_pstate_calc_busy(cpu, &cpu->samples[cpu->sample_ptr]);
- }
+ cpu->sample_ptr = (cpu->sample_ptr + 1) % SAMPLE_COUNT;
+ cpu->samples[cpu->sample_ptr].aperf = aperf;
+ cpu->samples[cpu->sample_ptr].mperf = mperf;
+ cpu->samples[cpu->sample_ptr].aperf -= cpu->prev_aperf;
+ cpu->samples[cpu->sample_ptr].mperf -= cpu->prev_mperf;
+
+ intel_pstate_calc_busy(cpu, &cpu->samples[cpu->sample_ptr]);
- cpu->prev_sample = now;
- cpu->prev_idle_time_us = idle_time_us;
cpu->prev_aperf = aperf;
cpu->prev_mperf = mperf;
}