Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

[sfrench/cifs-2.6.git] / arch / x86 / kernel / cpu / aperfmperf.c

diff --git a/arch/x86/kernel/cpu/aperfmperf.c b/arch/x86/kernel/cpu/aperfmperf.c
index 957813e0180d278563bf33289c54c7462ca83a8a..7eba34df54c3d44e17e3685321a7e9a6ca3b0f25 100644 (file)
--- a/arch/x86/kernel/cpu/aperfmperf.c
+++ b/arch/x86/kernel/cpu/aperfmperf.c
@@ -14,6 +14,8 @@
 #include <linux/percpu.h>
 #include <linux/smp.h>
 
+#include "cpu.h"
+
 struct aperfmperf_sample {
        unsigned int    khz;
        ktime_t time;
@@ -24,7 +26,7 @@ struct aperfmperf_sample {
 static DEFINE_PER_CPU(struct aperfmperf_sample, samples);
 
 #define APERFMPERF_CACHE_THRESHOLD_MS  10
-#define APERFMPERF_REFRESH_DELAY_MS    20
+#define APERFMPERF_REFRESH_DELAY_MS    10
 #define APERFMPERF_STALE_THRESHOLD_MS  1000
 
 /*
@@ -38,8 +40,6 @@ static void aperfmperf_snapshot_khz(void *dummy)
        u64 aperf, aperf_delta;
        u64 mperf, mperf_delta;
        struct aperfmperf_sample *s = this_cpu_ptr(&samples);
-       ktime_t now = ktime_get();
-       s64 time_delta = ktime_ms_delta(now, s->time);
        unsigned long flags;
 
        local_irq_save(flags);
@@ -57,38 +57,68 @@ static void aperfmperf_snapshot_khz(void *dummy)
        if (mperf_delta == 0)
                return;
 
-       s->time = now;
+       s->time = ktime_get();
        s->aperf = aperf;
        s->mperf = mperf;
-
-       /* If the previous iteration was too long ago, discard it. */
-       if (time_delta > APERFMPERF_STALE_THRESHOLD_MS)
-               s->khz = 0;
-       else
-               s->khz = div64_u64((cpu_khz * aperf_delta), mperf_delta);
+       s->khz = div64_u64((cpu_khz * aperf_delta), mperf_delta);
 }
 
-unsigned int arch_freq_get_on_cpu(int cpu)
+static bool aperfmperf_snapshot_cpu(int cpu, ktime_t now, bool wait)
 {
-       s64 time_delta;
-       unsigned int khz;
+       s64 time_delta = ktime_ms_delta(now, per_cpu(samples.time, cpu));
+
+       /* Don't bother re-computing within the cache threshold time. */
+       if (time_delta < APERFMPERF_CACHE_THRESHOLD_MS)
+               return true;
+
+       smp_call_function_single(cpu, aperfmperf_snapshot_khz, NULL, wait);
+
+       /* Return false if the previous iteration was too long ago. */
+       return time_delta <= APERFMPERF_STALE_THRESHOLD_MS;
+}
 
+unsigned int aperfmperf_get_khz(int cpu)
+{
        if (!cpu_khz)
                return 0;
 
        if (!static_cpu_has(X86_FEATURE_APERFMPERF))
                return 0;
 
-       /* Don't bother re-computing within the cache threshold time. */
-       time_delta = ktime_ms_delta(ktime_get(), per_cpu(samples.time, cpu));
-       khz = per_cpu(samples.khz, cpu);
-       if (khz && time_delta < APERFMPERF_CACHE_THRESHOLD_MS)
-               return khz;
+       aperfmperf_snapshot_cpu(cpu, ktime_get(), true);
+       return per_cpu(samples.khz, cpu);
+}
 
-       smp_call_function_single(cpu, aperfmperf_snapshot_khz, NULL, 1);
-       khz = per_cpu(samples.khz, cpu);
-       if (khz)
-               return khz;
+void arch_freq_prepare_all(void)
+{
+       ktime_t now = ktime_get();
+       bool wait = false;
+       int cpu;
+
+       if (!cpu_khz)
+               return;
+
+       if (!static_cpu_has(X86_FEATURE_APERFMPERF))
+               return;
+
+       for_each_online_cpu(cpu)
+               if (!aperfmperf_snapshot_cpu(cpu, now, false))
+                       wait = true;
+
+       if (wait)
+               msleep(APERFMPERF_REFRESH_DELAY_MS);
+}
+
+unsigned int arch_freq_get_on_cpu(int cpu)
+{
+       if (!cpu_khz)
+               return 0;
+
+       if (!static_cpu_has(X86_FEATURE_APERFMPERF))
+               return 0;
+
+       if (aperfmperf_snapshot_cpu(cpu, ktime_get(), true))
+               return per_cpu(samples.khz, cpu);
 
        msleep(APERFMPERF_REFRESH_DELAY_MS);
        smp_call_function_single(cpu, aperfmperf_snapshot_khz, NULL, 1);