From 47fe38fcff0517e67d395c039d2e26d2de688a60 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 2 Sep 2009 13:49:18 +0200 Subject: x86: sched: Provide arch implementations using aperf/mperf APERF/MPERF support for cpu_power. APERF/MPERF is arch defined to be a relative scale of work capacity per logical cpu, this is assumed to include SMT and Turbo mode. APERF/MPERF are specified to both reset to 0 when either counter wraps, which is highly inconvenient, since that'll give a blimp when that happens. The manual specifies writing 0 to the counters after each read, but that's 1) too expensive, and 2) destroys the possibility of sharing these counters with other users, so we live with the blimp - the other existing user does too. Signed-off-by: Peter Zijlstra LKML-Reference: Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/Makefile | 2 +- arch/x86/kernel/cpu/sched.c | 55 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 56 insertions(+), 1 deletion(-) create mode 100644 arch/x86/kernel/cpu/sched.c (limited to 'arch') diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile index c1f253dac15..8dd30638fe4 100644 --- a/arch/x86/kernel/cpu/Makefile +++ b/arch/x86/kernel/cpu/Makefile @@ -13,7 +13,7 @@ CFLAGS_common.o := $(nostackp) obj-y := intel_cacheinfo.o addon_cpuid_features.o obj-y += proc.o capflags.o powerflags.o common.o -obj-y += vmware.o hypervisor.o +obj-y += vmware.o hypervisor.o sched.o obj-$(CONFIG_X86_32) += bugs.o cmpxchg.o obj-$(CONFIG_X86_64) += bugs_64.o diff --git a/arch/x86/kernel/cpu/sched.c b/arch/x86/kernel/cpu/sched.c new file mode 100644 index 00000000000..6c00a8f3cce --- /dev/null +++ b/arch/x86/kernel/cpu/sched.c @@ -0,0 +1,55 @@ +#include +#include +#include +#include + +#include +#include + +#ifdef CONFIG_SMP + +static DEFINE_PER_CPU(struct aperfmperf, old_perf); + +static unsigned long scale_aperfmperf(void) +{ + struct aperfmperf val, *old = &__get_cpu_var(old_perf); + unsigned long ratio, flags; + + local_irq_save(flags); + get_aperfmperf(&val); + local_irq_restore(flags); + + ratio = calc_aperfmperf_ratio(old, &val); + *old = val; + + return ratio; +} + +unsigned long arch_scale_freq_power(struct sched_domain *sd, int cpu) +{ + /* + * do aperf/mperf on the cpu level because it includes things + * like turbo mode, which are relevant to full cores. + */ + if (boot_cpu_has(X86_FEATURE_APERFMPERF)) + return scale_aperfmperf(); + + /* + * maybe have something cpufreq here + */ + + return default_scale_freq_power(sd, cpu); +} + +unsigned long arch_scale_smt_power(struct sched_domain *sd, int cpu) +{ + /* + * aperf/mperf already includes the smt gain + */ + if (boot_cpu_has(X86_FEATURE_APERFMPERF)) + return SCHED_LOAD_SCALE; + + return default_scale_smt_power(sd, cpu); +} + +#endif -- cgit v1.2.3