diff options
Diffstat (limited to 'arch/x86/kernel/cpu/aperfmperf.c')
| -rw-r--r-- | arch/x86/kernel/cpu/aperfmperf.c | 71 |
1 files changed, 52 insertions, 19 deletions
diff --git a/arch/x86/kernel/cpu/aperfmperf.c b/arch/x86/kernel/cpu/aperfmperf.c index 0ee83321a313..7eba34df54c3 100644 --- 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 /* @@ -38,14 +40,8 @@ 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; - /* Don't bother re-computing within the cache threshold time. */ - if (time_delta < APERFMPERF_CACHE_THRESHOLD_MS) - return; - local_irq_save(flags); rdmsrl(MSR_IA32_APERF, aperf); rdmsrl(MSR_IA32_MPERF, mperf); @@ -61,31 +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; + s->khz = div64_u64((cpu_khz * aperf_delta), mperf_delta); +} - /* 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); +static bool aperfmperf_snapshot_cpu(int cpu, ktime_t now, bool wait) +{ + 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 arch_freq_get_on_cpu(int cpu) +unsigned int aperfmperf_get_khz(int cpu) { - unsigned int khz; + if (!cpu_khz) + return 0; + + if (!static_cpu_has(X86_FEATURE_APERFMPERF)) + return 0; + aperfmperf_snapshot_cpu(cpu, ktime_get(), true); + return per_cpu(samples.khz, cpu); +} + +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; - smp_call_function_single(cpu, aperfmperf_snapshot_khz, NULL, 1); - khz = per_cpu(samples.khz, cpu); - if (khz) - return khz; + 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); |