[PATCH 3/6] intel_pstate: Take core C0 time into account for core busy calculation
Colin King
colin.king at canonical.com
Tue Mar 4 13:42:10 UTC 2014
From: Dirk Brandewie <dirk.j.brandewie at intel.com>
Take non-idle time into account when calculating core busy time.
This ensures that intel_pstate will notice a decrease in load.
References: https://bugzilla.kernel.org/show_bug.cgi?id=66581
Cc: 3.10+ <stable at vger.kernel.org> # 3.10+
Signed-off-by: Dirk Brandewie <dirk.j.brandewie at intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
---
drivers/cpufreq/intel_pstate.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index b74dc71..e9de314f 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -57,6 +57,7 @@ struct sample {
int32_t core_pct_busy;
u64 aperf;
u64 mperf;
+ unsigned long long tsc;
int freq;
};
@@ -96,6 +97,7 @@ struct cpudata {
u64 prev_aperf;
u64 prev_mperf;
+ unsigned long long prev_tsc;
int sample_ptr;
struct sample samples[SAMPLE_COUNT];
};
@@ -548,30 +550,41 @@ static inline void intel_pstate_calc_busy(struct cpudata *cpu,
struct sample *sample)
{
u64 core_pct;
- core_pct = div64_u64(int_tofp(sample->aperf * 100),
- sample->mperf);
- sample->freq = fp_toint(cpu->pstate.max_pstate * core_pct * 1000);
+ u64 c0_pct;
- sample->core_pct_busy = core_pct;
+ core_pct = div64_u64(sample->aperf * 100, sample->mperf);
+
+ c0_pct = div64_u64(sample->mperf * 100, sample->tsc);
+ sample->freq = fp_toint(
+ mul_fp(int_tofp(cpu->pstate.max_pstate),
+ int_tofp(core_pct * 1000)));
+
+ sample->core_pct_busy = mul_fp(int_tofp(core_pct),
+ div_fp(int_tofp(c0_pct + 1), int_tofp(100)));
}
static inline void intel_pstate_sample(struct cpudata *cpu)
{
u64 aperf, mperf;
+ unsigned long long tsc;
rdmsrl(MSR_IA32_APERF, aperf);
rdmsrl(MSR_IA32_MPERF, mperf);
+ tsc = native_read_tsc();
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].tsc = tsc;
cpu->samples[cpu->sample_ptr].aperf -= cpu->prev_aperf;
cpu->samples[cpu->sample_ptr].mperf -= cpu->prev_mperf;
+ cpu->samples[cpu->sample_ptr].tsc -= cpu->prev_tsc;
intel_pstate_calc_busy(cpu, &cpu->samples[cpu->sample_ptr]);
cpu->prev_aperf = aperf;
cpu->prev_mperf = mperf;
+ cpu->prev_tsc = tsc;
}
static inline void intel_pstate_set_sample_time(struct cpudata *cpu)
--
1.7.9.5
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