diff options
Diffstat (limited to 'arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c')
| -rw-r--r-- | arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c | 107 |
1 files changed, 106 insertions, 1 deletions
diff --git a/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c index 8b0c7db85a47..f8a8e46acb78 100644 --- a/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c +++ b/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c @@ -58,10 +58,12 @@ enum { }; #define INTEL_MSR_RANGE (0xffff) +#define CPUID_6_ECX_APERFMPERF_CAPABILITY (0x1) struct acpi_cpufreq_data { struct acpi_processor_performance *acpi_data; struct cpufreq_frequency_table *freq_table; + unsigned int max_freq; unsigned int resume; unsigned int cpu_feature; }; @@ -258,6 +260,100 @@ static u32 get_cur_val(cpumask_t mask) return cmd.val; } +/* + * Return the measured active (C0) frequency on this CPU since last call + * to this function. + * Input: cpu number + * Return: Average CPU frequency in terms of max frequency (zero on error) + * + * We use IA32_MPERF and IA32_APERF MSRs to get the measured performance + * over a period of time, while CPU is in C0 state. + * IA32_MPERF counts at the rate of max advertised frequency + * IA32_APERF counts at the rate of actual CPU frequency + * Only IA32_APERF/IA32_MPERF ratio is architecturally defined and + * no meaning should be associated with absolute values of these MSRs. + */ +static unsigned int get_measured_perf(unsigned int cpu) +{ + union { + struct { + u32 lo; + u32 hi; + } split; + u64 whole; + } aperf_cur, mperf_cur; + + cpumask_t saved_mask; + unsigned int perf_percent; + unsigned int retval; + + saved_mask = current->cpus_allowed; + set_cpus_allowed(current, cpumask_of_cpu(cpu)); + if (get_cpu() != cpu) { + /* We were not able to run on requested processor */ + put_cpu(); + return 0; + } + + rdmsr(MSR_IA32_APERF, aperf_cur.split.lo, aperf_cur.split.hi); + rdmsr(MSR_IA32_MPERF, mperf_cur.split.lo, mperf_cur.split.hi); + + wrmsr(MSR_IA32_APERF, 0,0); + wrmsr(MSR_IA32_MPERF, 0,0); + +#ifdef __i386__ + /* + * We dont want to do 64 bit divide with 32 bit kernel + * Get an approximate value. Return failure in case we cannot get + * an approximate value. + */ + if (unlikely(aperf_cur.split.hi || mperf_cur.split.hi)) { + int shift_count; + u32 h; + + h = max_t(u32, aperf_cur.split.hi, mperf_cur.split.hi); + shift_count = fls(h); + + aperf_cur.whole >>= shift_count; + mperf_cur.whole >>= shift_count; + } + + if (((unsigned long)(-1) / 100) < aperf_cur.split.lo) { + int shift_count = 7; + aperf_cur.split.lo >>= shift_count; + mperf_cur.split.lo >>= shift_count; + } + + if (aperf_cur.split.lo && mperf_cur.split.lo) { + perf_percent = (aperf_cur.split.lo * 100) / mperf_cur.split.lo; + } else { + perf_percent = 0; + } + +#else + if (unlikely(((unsigned long)(-1) / 100) < aperf_cur.whole)) { + int shift_count = 7; + aperf_cur.whole >>= shift_count; + mperf_cur.whole >>= shift_count; + } + + if (aperf_cur.whole && mperf_cur.whole) { + perf_percent = (aperf_cur.whole * 100) / mperf_cur.whole; + } else { + perf_percent = 0; + } + +#endif + + retval = drv_data[cpu]->max_freq * perf_percent / 100; + + put_cpu(); + set_cpus_allowed(current, saved_mask); + + dprintk("cpu %d: performance percent %d\n", cpu, perf_percent); + return retval; +} + static unsigned int get_cur_freq_on_cpu(unsigned int cpu) { struct acpi_cpufreq_data *data = drv_data[cpu]; @@ -497,7 +593,6 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy) unsigned int valid_states = 0; unsigned int cpu = policy->cpu; struct acpi_cpufreq_data *data; - unsigned int l, h; unsigned int result = 0; struct cpuinfo_x86 *c = &cpu_data[policy->cpu]; struct acpi_processor_performance *perf; @@ -591,6 +686,7 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy) } policy->governor = CPUFREQ_DEFAULT_GOVERNOR; + data->max_freq = perf->states[0].core_frequency * 1000; /* table init */ for (i = 0; i < perf->state_count; i++) { if (i > 0 && perf->states[i].core_frequency == @@ -625,6 +721,15 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy) /* notify BIOS that we exist */ acpi_processor_notify_smm(THIS_MODULE); + /* Check for APERF/MPERF support in hardware */ + if (c->x86_vendor == X86_VENDOR_INTEL && c->cpuid_level >= 6) { + unsigned int ecx; + ecx = cpuid_ecx(6); + if (ecx & CPUID_6_ECX_APERFMPERF_CAPABILITY) { + acpi_cpufreq_driver.getavg = get_measured_perf; + } + } + dprintk("CPU%u - ACPI performance management activated.\n", cpu); for (i = 0; i < perf->state_count; i++) dprintk(" %cP%d: %d MHz, %d mW, %d uS\n", |