intel_pstate: Add trace point to report internal state.

Add perf trace event "power:pstate_sample" to report driver state to
aid in diagnosing issues reported against intel_pstate.

Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index fe91dad8f5e..7e257b23360 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -51,6 +51,8 @@ static inline int32_t div_fp(int32_t x, int32_t y)
 	return div_s64((int64_t)x << FRAC_BITS, (int64_t)y);
 }
 
+static u64 energy_divisor;
+
 struct sample {
 	int32_t core_pct_busy;
 	u64 aperf;
@@ -559,6 +561,7 @@ static inline void intel_pstate_sample(struct cpudata *cpu)
 
 	rdmsrl(MSR_IA32_APERF, aperf);
 	rdmsrl(MSR_IA32_MPERF, mperf);
+
 	cpu->sample_ptr = (cpu->sample_ptr + 1) % SAMPLE_COUNT;
 	cpu->samples[cpu->sample_ptr].aperf = aperf;
 	cpu->samples[cpu->sample_ptr].mperf = mperf;
@@ -603,6 +606,7 @@ static inline void intel_pstate_adjust_busy_pstate(struct cpudata *cpu)
 	ctl = pid_calc(pid, busy_scaled);
 
 	steps = abs(ctl);
+
 	if (ctl < 0)
 		intel_pstate_pstate_increase(cpu, steps);
 	else
@@ -612,9 +616,24 @@ static inline void intel_pstate_adjust_busy_pstate(struct cpudata *cpu)
 static void intel_pstate_timer_func(unsigned long __data)
 {
 	struct cpudata *cpu = (struct cpudata *) __data;
+	struct sample *sample;
+	u64 energy;
 
 	intel_pstate_sample(cpu);
+
+	sample = &cpu->samples[cpu->sample_ptr];
+	rdmsrl(MSR_PKG_ENERGY_STATUS, energy);
+
 	intel_pstate_adjust_busy_pstate(cpu);
+
+	trace_pstate_sample(fp_toint(sample->core_pct_busy),
+			fp_toint(intel_pstate_get_scaled_busy(cpu)),
+			cpu->pstate.current_pstate,
+			sample->mperf,
+			sample->aperf,
+			div64_u64(energy, energy_divisor),
+			sample->freq);
+
 	intel_pstate_set_sample_time(cpu);
 }
 
@@ -894,6 +913,7 @@ static int __init intel_pstate_init(void)
 	int cpu, rc = 0;
 	const struct x86_cpu_id *id;
 	struct cpu_defaults *cpu_info;
+	u64 units;
 
 	if (no_load)
 		return -ENODEV;
@@ -927,8 +947,12 @@ static int __init intel_pstate_init(void)
 	if (rc)
 		goto out;
 
+	rdmsrl(MSR_RAPL_POWER_UNIT, units);
+	energy_divisor = 1 << ((units >> 8) & 0x1f); /* bits{12:8} */
+
 	intel_pstate_debug_expose_params();
 	intel_pstate_sysfs_expose_params();
+
 	return rc;
 out:
 	get_online_cpus();