Merge tag 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford...

[linux-2.6-microblaze.git] / drivers / cpufreq / intel_pstate.c

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 806f203..f535f81 100644 (file)
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -225,7 +225,7 @@ struct cpudata {
 static struct cpudata **all_cpu_data;
 
 /**
- * struct pid_adjust_policy - Stores static PID configuration data
+ * struct pstate_adjust_policy - Stores static PID configuration data
  * @sample_rate_ms:    PID calculation sample rate in ms
  * @sample_rate_ns:    Sample rate calculation in ns
  * @deadband:          PID deadband
@@ -562,12 +562,12 @@ static void intel_pstate_hwp_set(const struct cpumask *cpumask)
        int min, hw_min, max, hw_max, cpu, range, adj_range;
        u64 value, cap;
 
-       rdmsrl(MSR_HWP_CAPABILITIES, cap);
-       hw_min = HWP_LOWEST_PERF(cap);
-       hw_max = HWP_HIGHEST_PERF(cap);
-       range = hw_max - hw_min;
-
        for_each_cpu(cpu, cpumask) {
+               rdmsrl_on_cpu(cpu, MSR_HWP_CAPABILITIES, &cap);
+               hw_min = HWP_LOWEST_PERF(cap);
+               hw_max = HWP_HIGHEST_PERF(cap);
+               range = hw_max - hw_min;
+
                rdmsrl_on_cpu(cpu, MSR_HWP_REQUEST, &value);
                adj_range = limits->min_perf_pct * range / 100;
                min = hw_min + adj_range;
@@ -1232,6 +1232,7 @@ static inline int32_t get_target_pstate_use_cpu_load(struct cpudata *cpu)
 {
        struct sample *sample = &cpu->sample;
        int32_t busy_frac, boost;
+       int target, avg_pstate;
 
        busy_frac = div_fp(sample->mperf, sample->tsc);
 
@@ -1242,7 +1243,26 @@ static inline int32_t get_target_pstate_use_cpu_load(struct cpudata *cpu)
                busy_frac = boost;
 
        sample->busy_scaled = busy_frac * 100;
-       return get_avg_pstate(cpu) - pid_calc(&cpu->pid, sample->busy_scaled);
+
+       target = limits->no_turbo || limits->turbo_disabled ?
+                       cpu->pstate.max_pstate : cpu->pstate.turbo_pstate;
+       target += target >> 2;
+       target = mul_fp(target, busy_frac);
+       if (target < cpu->pstate.min_pstate)
+               target = cpu->pstate.min_pstate;
+
+       /*
+        * If the average P-state during the previous cycle was higher than the
+        * current target, add 50% of the difference to the target to reduce
+        * possible performance oscillations and offset possible performance
+        * loss related to moving the workload from one CPU to another within
+        * a package/module.
+        */
+       avg_pstate = get_avg_pstate(cpu);
+       if (avg_pstate > target)
+               target += (avg_pstate - target) >> 1;
+
+       return target;
 }
 
 static inline int32_t get_target_pstate_use_performance(struct cpudata *cpu)
@@ -1251,10 +1271,11 @@ static inline int32_t get_target_pstate_use_performance(struct cpudata *cpu)
        u64 duration_ns;
 
        /*
-        * perf_scaled is the average performance during the last sampling
-        * period scaled by the ratio of the maximum P-state to the P-state
-        * requested last time (in percent).  That measures the system's
-        * response to the previous P-state selection.
+        * perf_scaled is the ratio of the average P-state during the last
+        * sampling period to the P-state requested last time (in percent).
+        *
+        * That measures the system's response to the previous P-state
+        * selection.
         */
        max_pstate = cpu->pstate.max_pstate_physical;
        current_pstate = cpu->pstate.current_pstate;