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authorLinus Torvalds <torvalds@linux-foundation.org>2017-08-03 12:32:49 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-08-03 12:32:49 -0700
commit73784fb73be6fc0a5a204468bc39a2b95f28424b (patch)
tree8c1816283e05bb7fadf2ae2fb4b9857c7613f356 /arch
parent19ec50a438c2ea3e370f6d453bf2f2e6e45ef72b (diff)
parent78aa904a773bfd008606c2065709e23173180ace (diff)
Merge tag 'pm-4.13-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki: "These fix two cpufreq issues, one introduced recently and one related to recent changes, fix cpufreq documentation, fix up recently added code in the Thunderbolt driver and update runtime PM framework documentation. Specifics: - Fix the handling of the scaling_cur_freq cpufreq policy attribute on x86 systems with the MPERF/APERF registers present to make it behave more as expected after recent changes (Rafael Wysocki). - Drop a leftover callback from the intel_pstate driver which also prevents the cpuinfo_cur_freq cpufreq policy attribute from being incorrectly exposed when intel_pstate works in the active mode (Rafael Wysocki). - Add a missing piece describing the cpuinfo_cur_freq policy attribute to cpufreq documentation (Rafael Wysocki). - Fix up a recently added part of the Thunderbolt driver to avoid aborting system suspends if its mailbox commands time out (Rafael Wysocki). - Update device runtime PM framework documentation to reflect the current behavior of the code (Johan Hovold)" * tag 'pm-4.13-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: thunderbolt: icm: Ignore mailbox errors in icm_suspend() cpufreq: x86: Make scaling_cur_freq behave more as expected PM / runtime: Document new pm_runtime_set_suspended() constraint cpufreq: docs: Add missing cpuinfo_cur_freq description cpufreq: intel_pstate: Drop ->get from intel_pstate structure
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/cpu/aperfmperf.c40
1 files changed, 26 insertions, 14 deletions
diff --git a/arch/x86/kernel/cpu/aperfmperf.c b/arch/x86/kernel/cpu/aperfmperf.c
index d869c8671e36..7cf7c70b6ef2 100644
--- 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);
}