From: Dirk Brandewie <dirk.j.brandewie@xxxxxxxxx> 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 https://bugzilla.kernel.org/show_bug.cgi?id=56691 Reported-by: Mike Lothian <mike@xxxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Dirk Brandewie <dirk.j.brandewie@xxxxxxxxx> --- drivers/cpufreq/intel_pstate.c | 45 +++++++-------------------------------- 1 files changed, 8 insertions(+), 37 deletions(-) diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 4d6b988..5370b8d 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; } -- 1.7.7.6 -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
