Merge branches 'pm-cpufreq-x86', 'pm-cpufreq-docs' and 'intel_pstate'

* pm-cpufreq-x86:
  cpufreq: x86: Make scaling_cur_freq behave more as expected

* pm-cpufreq-docs:
  cpufreq: docs: Add missing cpuinfo_cur_freq description

* intel_pstate:
  cpufreq: intel_pstate: Drop ->get from intel_pstate structure

diff --git a/Documentation/admin-guide/pm/cpufreq.rst b/Documentation/admin-guide/pm/cpufreq.rst
index 463cf7e73db80b3bf3f8a36afe91bcf3d7f0d429..7af83a92d2d6103ea3fb0a3a0425e994b29f7f53 100644 (file)
--- a/Documentation/admin-guide/pm/cpufreq.rst
+++ b/Documentation/admin-guide/pm/cpufreq.rst
@@ -237,6 +237,14 @@ are the following:
        This attribute is not present if the scaling driver in use does not
        support it.
 
+``cpuinfo_cur_freq``
+       Current frequency of the CPUs belonging to this policy as obtained from
+       the hardware (in KHz).
+
+       This is expected to be the frequency the hardware actually runs at.
+       If that frequency cannot be determined, this attribute should not
+       be present.
+
 ``cpuinfo_max_freq``
        Maximum possible operating frequency the CPUs belonging to this policy
        can run at (in kHz).

diff --git a/arch/x86/kernel/cpu/aperfmperf.c b/arch/x86/kernel/cpu/aperfmperf.c
index d869c8671e364d55e343322b410fec9a3e5f66c6..7cf7c70b6ef2a20483361fb8333a85ace25bf1d7 100644 (file)
--- a/arch/x86/kernel/cpu/aperfmperf.c
+++ b/arch/x86/kernel/cpu/aperfmperf.c
@@ -8,20 +8,25 @@
  * This file is licensed under GPLv2.
  */
 
-#include <linux/jiffies.h>
+#include <linux/delay.h>
+#include <linux/ktime.h>
 #include <linux/math64.h>
 #include <linux/percpu.h>
 #include <linux/smp.h>
 
 struct aperfmperf_sample {
        unsigned int    khz;
-       unsigned long   jiffies;
+       ktime_t time;
        u64     aperf;
        u64     mperf;
 };
 
 static DEFINE_PER_CPU(struct aperfmperf_sample, samples);
 
+#define APERFMPERF_CACHE_THRESHOLD_MS  10
+#define APERFMPERF_REFRESH_DELAY_MS    20
+#define APERFMPERF_STALE_THRESHOLD_MS  1000
+
 /*
  * aperfmperf_snapshot_khz()
  * On the current CPU, snapshot APERF, MPERF, and jiffies
@@ -33,9 +38,11 @@ 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);
 
-       /* Don't bother re-computing within 10 ms */
-       if (time_before(jiffies, s->jiffies + HZ/100))
+       /* Don't bother re-computing within the cache threshold time. */
+       if (time_delta < APERFMPERF_CACHE_THRESHOLD_MS)
                return;
 
        rdmsrl(MSR_IA32_APERF, aperf);
@@ -51,22 +58,21 @@ static void aperfmperf_snapshot_khz(void *dummy)
        if (mperf_delta == 0)
                return;
 
-       /*
-        * if (cpu_khz * aperf_delta) fits into ULLONG_MAX, then
-        *      khz = (cpu_khz * aperf_delta) / mperf_delta
-        */
-       if (div64_u64(ULLONG_MAX, cpu_khz) > aperf_delta)
-               s->khz = div64_u64((cpu_khz * aperf_delta), mperf_delta);
-       else    /* khz = aperf_delta / (mperf_delta / cpu_khz) */
-               s->khz = div64_u64(aperf_delta,
-                       div64_u64(mperf_delta, cpu_khz));
-       s->jiffies = jiffies;
+       s->time = now;
        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);
 }
 
 unsigned int arch_freq_get_on_cpu(int cpu)
 {
+       unsigned int khz;
+
        if (!cpu_khz)
                return 0;
 
@@ -74,6 +80,12 @@ unsigned int arch_freq_get_on_cpu(int cpu)
                return 0;
 
        smp_call_function_single(cpu, aperfmperf_snapshot_khz, NULL, 1);
+       khz = per_cpu(samples.khz, cpu);
+       if (khz)
+               return khz;
+
+       msleep(APERFMPERF_REFRESH_DELAY_MS);
+       smp_call_function_single(cpu, aperfmperf_snapshot_khz, NULL, 1);
 
        return per_cpu(samples.khz, cpu);
 }

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 6cd50352563894bea24866d2d36d6b815d0abc20..0566455f233ed3cd663506321f08f7ae546862be 100644 (file)
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -1922,13 +1922,6 @@ static int intel_pstate_init_cpu(unsigned int cpunum)
        return 0;
 }
 
-static unsigned int intel_pstate_get(unsigned int cpu_num)
-{
-       struct cpudata *cpu = all_cpu_data[cpu_num];
-
-       return cpu ? get_avg_frequency(cpu) : 0;
-}
-
 static void intel_pstate_set_update_util_hook(unsigned int cpu_num)
 {
        struct cpudata *cpu = all_cpu_data[cpu_num];
@@ -2169,7 +2162,6 @@ static struct cpufreq_driver intel_pstate = {
        .setpolicy      = intel_pstate_set_policy,
        .suspend        = intel_pstate_hwp_save_state,
        .resume         = intel_pstate_resume,
-       .get            = intel_pstate_get,
        .init           = intel_pstate_cpu_init,
        .exit           = intel_pstate_cpu_exit,
        .stop_cpu       = intel_pstate_stop_cpu,