intel_pstate: Do not skip samples partially
If the current value of MPERF or the current value of TSC is the same as the previous one, respectively, intel_pstate_sample() bails out early and skips the sample. However, intel_pstate_adjust_busy_pstate() is still called in that case which is not correct, so modify intel_pstate_sample() to return a bool value indicating whether or not the sample has been taken and use it to decide whether or not to call intel_pstate_adjust_busy_pstate(). While at it, remove redundant parentheses from the MPERF/TSC check in intel_pstate_sample(). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
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@ -884,7 +884,7 @@ static inline void intel_pstate_calc_busy(struct cpudata *cpu)
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sample->core_pct_busy = (int32_t)core_pct;
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sample->core_pct_busy = (int32_t)core_pct;
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}
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}
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static inline void intel_pstate_sample(struct cpudata *cpu, u64 time)
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static inline bool intel_pstate_sample(struct cpudata *cpu, u64 time)
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{
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{
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u64 aperf, mperf;
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u64 aperf, mperf;
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unsigned long flags;
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unsigned long flags;
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@ -894,9 +894,9 @@ static inline void intel_pstate_sample(struct cpudata *cpu, u64 time)
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rdmsrl(MSR_IA32_APERF, aperf);
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rdmsrl(MSR_IA32_APERF, aperf);
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rdmsrl(MSR_IA32_MPERF, mperf);
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rdmsrl(MSR_IA32_MPERF, mperf);
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tsc = rdtsc();
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tsc = rdtsc();
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if ((cpu->prev_mperf == mperf) || (cpu->prev_tsc == tsc)) {
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if (cpu->prev_mperf == mperf || cpu->prev_tsc == tsc) {
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local_irq_restore(flags);
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local_irq_restore(flags);
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return;
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return false;
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}
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}
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local_irq_restore(flags);
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local_irq_restore(flags);
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@ -912,6 +912,7 @@ static inline void intel_pstate_sample(struct cpudata *cpu, u64 time)
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cpu->prev_aperf = aperf;
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cpu->prev_aperf = aperf;
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cpu->prev_mperf = mperf;
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cpu->prev_mperf = mperf;
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cpu->prev_tsc = tsc;
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cpu->prev_tsc = tsc;
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return true;
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}
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}
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static inline int32_t get_avg_frequency(struct cpudata *cpu)
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static inline int32_t get_avg_frequency(struct cpudata *cpu)
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@ -1025,8 +1026,9 @@ static void intel_pstate_update_util(struct update_util_data *data, u64 time,
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u64 delta_ns = time - cpu->sample.time;
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u64 delta_ns = time - cpu->sample.time;
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if ((s64)delta_ns >= pid_params.sample_rate_ns) {
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if ((s64)delta_ns >= pid_params.sample_rate_ns) {
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intel_pstate_sample(cpu, time);
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bool sample_taken = intel_pstate_sample(cpu, time);
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if (!hwp_active)
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if (sample_taken && !hwp_active)
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intel_pstate_adjust_busy_pstate(cpu);
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intel_pstate_adjust_busy_pstate(cpu);
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}
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}
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}
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}
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