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Commit d33a2a91 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'pm-4.13-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm 

Pull power management fixes from Rafael Wysocki:
 "These fix two issues related to exposing the current CPU frequency to
  user space on x86.

  Specifics:

   - Disable interrupts around reading IA32_APERF and IA32_MPERF in
     aperfmperf_snapshot_khz() (introduced recently) to avoid excessive
     delays between the reads that may result from interrupt handling
     (Doug Smythies).

   - Fix the computation of the CPU frequency to be reported through the
     pstate_sample tracepoint in intel_pstate (Doug Smythies)"

* tag 'pm-4.13-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpufreq: x86: Disable interrupts during MSRs reading
  cpufreq: intel_pstate: report correct CPU frequencies during trace
parents 440105d3 8179962b

arch/x86/kernel/cpu/aperfmperf.c

+3 −0
Original line number Diff line number Diff line
@@ -40,13 +40,16 @@ static void aperfmperf_snapshot_khz(void *dummy) 
	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);

	local_irq_restore(flags);



	aperf_delta = aperf - s->aperf;

	mperf_delta = mperf - s->mperf;

drivers/cpufreq/intel_pstate.c

+1 −2
Original line number Diff line number Diff line
@@ -1613,8 +1613,7 @@ static inline bool intel_pstate_sample(struct cpudata *cpu, u64 time) 


static inline int32_t get_avg_frequency(struct cpudata *cpu)

{

	return mul_ext_fp(cpu->sample.core_avg_perf,

			  cpu->pstate.max_pstate_physical * cpu->pstate.scaling);

	return mul_ext_fp(cpu->sample.core_avg_perf, cpu_khz);

}



static inline int32_t get_avg_pstate(struct cpudata *cpu)