diff options
Diffstat (limited to 'tools/power/cpupower/utils/idle_monitor/mperf_monitor.c')
| -rw-r--r-- | tools/power/cpupower/utils/idle_monitor/mperf_monitor.c | 338 |
1 files changed, 338 insertions, 0 deletions
diff --git a/tools/power/cpupower/utils/idle_monitor/mperf_monitor.c b/tools/power/cpupower/utils/idle_monitor/mperf_monitor.c new file mode 100644 index 000000000..90a8c4f07 --- /dev/null +++ b/tools/power/cpupower/utils/idle_monitor/mperf_monitor.c @@ -0,0 +1,338 @@ +/* + * (C) 2010,2011 Thomas Renninger <trenn@suse.de>, Novell Inc. + * + * Licensed under the terms of the GNU GPL License version 2. + */ + +#if defined(__i386__) || defined(__x86_64__) + +#include <stdio.h> +#include <stdint.h> +#include <stdlib.h> +#include <string.h> +#include <limits.h> + +#include <cpufreq.h> + +#include "helpers/helpers.h" +#include "idle_monitor/cpupower-monitor.h" + +#define MSR_APERF 0xE8 +#define MSR_MPERF 0xE7 + +#define MSR_TSC 0x10 + +#define MSR_AMD_HWCR 0xc0010015 + +enum mperf_id { C0 = 0, Cx, AVG_FREQ, MPERF_CSTATE_COUNT }; + +static int mperf_get_count_percent(unsigned int self_id, double *percent, + unsigned int cpu); +static int mperf_get_count_freq(unsigned int id, unsigned long long *count, + unsigned int cpu); +static struct timespec time_start, time_end; + +static cstate_t mperf_cstates[MPERF_CSTATE_COUNT] = { + { + .name = "C0", + .desc = N_("Processor Core not idle"), + .id = C0, + .range = RANGE_THREAD, + .get_count_percent = mperf_get_count_percent, + }, + { + .name = "Cx", + .desc = N_("Processor Core in an idle state"), + .id = Cx, + .range = RANGE_THREAD, + .get_count_percent = mperf_get_count_percent, + }, + + { + .name = "Freq", + .desc = N_("Average Frequency (including boost) in MHz"), + .id = AVG_FREQ, + .range = RANGE_THREAD, + .get_count = mperf_get_count_freq, + }, +}; + +enum MAX_FREQ_MODE { MAX_FREQ_SYSFS, MAX_FREQ_TSC_REF }; +static int max_freq_mode; +/* + * The max frequency mperf is ticking at (in C0), either retrieved via: + * 1) calculated after measurements if we know TSC ticks at mperf/P0 frequency + * 2) cpufreq /sys/devices/.../cpu0/cpufreq/cpuinfo_max_freq at init time + * 1. Is preferred as it also works without cpufreq subsystem (e.g. on Xen) + */ +static unsigned long max_frequency; + +static unsigned long long tsc_at_measure_start; +static unsigned long long tsc_at_measure_end; +static unsigned long long *mperf_previous_count; +static unsigned long long *aperf_previous_count; +static unsigned long long *mperf_current_count; +static unsigned long long *aperf_current_count; + +/* valid flag for all CPUs. If a MSR read failed it will be zero */ +static int *is_valid; + +static int mperf_get_tsc(unsigned long long *tsc) +{ + int ret; + ret = read_msr(0, MSR_TSC, tsc); + if (ret) + dprint("Reading TSC MSR failed, returning %llu\n", *tsc); + return ret; +} + +static int mperf_init_stats(unsigned int cpu) +{ + unsigned long long val; + int ret; + + ret = read_msr(cpu, MSR_APERF, &val); + aperf_previous_count[cpu] = val; + ret |= read_msr(cpu, MSR_MPERF, &val); + mperf_previous_count[cpu] = val; + is_valid[cpu] = !ret; + + return 0; +} + +static int mperf_measure_stats(unsigned int cpu) +{ + unsigned long long val; + int ret; + + ret = read_msr(cpu, MSR_APERF, &val); + aperf_current_count[cpu] = val; + ret |= read_msr(cpu, MSR_MPERF, &val); + mperf_current_count[cpu] = val; + is_valid[cpu] = !ret; + + return 0; +} + +static int mperf_get_count_percent(unsigned int id, double *percent, + unsigned int cpu) +{ + unsigned long long aperf_diff, mperf_diff, tsc_diff; + unsigned long long timediff; + + if (!is_valid[cpu]) + return -1; + + if (id != C0 && id != Cx) + return -1; + + mperf_diff = mperf_current_count[cpu] - mperf_previous_count[cpu]; + aperf_diff = aperf_current_count[cpu] - aperf_previous_count[cpu]; + + if (max_freq_mode == MAX_FREQ_TSC_REF) { + tsc_diff = tsc_at_measure_end - tsc_at_measure_start; + *percent = 100.0 * mperf_diff / tsc_diff; + dprint("%s: TSC Ref - mperf_diff: %llu, tsc_diff: %llu\n", + mperf_cstates[id].name, mperf_diff, tsc_diff); + } else if (max_freq_mode == MAX_FREQ_SYSFS) { + timediff = timespec_diff_us(time_start, time_end); + *percent = 100.0 * mperf_diff / timediff; + dprint("%s: MAXFREQ - mperf_diff: %llu, time_diff: %llu\n", + mperf_cstates[id].name, mperf_diff, timediff); + } else + return -1; + + if (id == Cx) + *percent = 100.0 - *percent; + + dprint("%s: previous: %llu - current: %llu - (%u)\n", + mperf_cstates[id].name, mperf_diff, aperf_diff, cpu); + dprint("%s: %f\n", mperf_cstates[id].name, *percent); + return 0; +} + +static int mperf_get_count_freq(unsigned int id, unsigned long long *count, + unsigned int cpu) +{ + unsigned long long aperf_diff, mperf_diff, time_diff, tsc_diff; + + if (id != AVG_FREQ) + return 1; + + if (!is_valid[cpu]) + return -1; + + mperf_diff = mperf_current_count[cpu] - mperf_previous_count[cpu]; + aperf_diff = aperf_current_count[cpu] - aperf_previous_count[cpu]; + + if (max_freq_mode == MAX_FREQ_TSC_REF) { + /* Calculate max_freq from TSC count */ + tsc_diff = tsc_at_measure_end - tsc_at_measure_start; + time_diff = timespec_diff_us(time_start, time_end); + max_frequency = tsc_diff / time_diff; + } + + *count = max_frequency * ((double)aperf_diff / mperf_diff); + dprint("%s: Average freq based on %s maximum frequency:\n", + mperf_cstates[id].name, + (max_freq_mode == MAX_FREQ_TSC_REF) ? "TSC calculated" : "sysfs read"); + dprint("%max_frequency: %lu", max_frequency); + dprint("aperf_diff: %llu\n", aperf_diff); + dprint("mperf_diff: %llu\n", mperf_diff); + dprint("avg freq: %llu\n", *count); + return 0; +} + +static int mperf_start(void) +{ + int cpu; + unsigned long long dbg; + + clock_gettime(CLOCK_REALTIME, &time_start); + mperf_get_tsc(&tsc_at_measure_start); + + for (cpu = 0; cpu < cpu_count; cpu++) + mperf_init_stats(cpu); + + mperf_get_tsc(&dbg); + dprint("TSC diff: %llu\n", dbg - tsc_at_measure_start); + return 0; +} + +static int mperf_stop(void) +{ + unsigned long long dbg; + int cpu; + + for (cpu = 0; cpu < cpu_count; cpu++) + mperf_measure_stats(cpu); + + mperf_get_tsc(&tsc_at_measure_end); + clock_gettime(CLOCK_REALTIME, &time_end); + + mperf_get_tsc(&dbg); + dprint("TSC diff: %llu\n", dbg - tsc_at_measure_end); + + return 0; +} + +/* + * Mperf register is defined to tick at P0 (maximum) frequency + * + * Instead of reading out P0 which can be tricky to read out from HW, + * we use TSC counter if it reliably ticks at P0/mperf frequency. + * + * Still try to fall back to: + * /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq + * on older Intel HW without invariant TSC feature. + * Or on AMD machines where TSC does not tick at P0 (do not exist yet, but + * it's still double checked (MSR_AMD_HWCR)). + * + * On these machines the user would still get useful mperf + * stats when acpi-cpufreq driver is loaded. + */ +static int init_maxfreq_mode(void) +{ + int ret; + unsigned long long hwcr; + unsigned long min; + + if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_INV_TSC)) + goto use_sysfs; + + if (cpupower_cpu_info.vendor == X86_VENDOR_AMD) { + /* MSR_AMD_HWCR tells us whether TSC runs at P0/mperf + * freq. + * A test whether hwcr is accessable/available would be: + * (cpupower_cpu_info.family > 0x10 || + * cpupower_cpu_info.family == 0x10 && + * cpupower_cpu_info.model >= 0x2)) + * This should be the case for all aperf/mperf + * capable AMD machines and is therefore safe to test here. + * Compare with Linus kernel git commit: acf01734b1747b1ec4 + */ + ret = read_msr(0, MSR_AMD_HWCR, &hwcr); + /* + * If the MSR read failed, assume a Xen system that did + * not explicitly provide access to it and assume TSC works + */ + if (ret != 0) { + dprint("TSC read 0x%x failed - assume TSC working\n", + MSR_AMD_HWCR); + return 0; + } else if (1 & (hwcr >> 24)) { + max_freq_mode = MAX_FREQ_TSC_REF; + return 0; + } else { /* Use sysfs max frequency if available */ } + } else if (cpupower_cpu_info.vendor == X86_VENDOR_INTEL) { + /* + * On Intel we assume mperf (in C0) is ticking at same + * rate than TSC + */ + max_freq_mode = MAX_FREQ_TSC_REF; + return 0; + } +use_sysfs: + if (cpufreq_get_hardware_limits(0, &min, &max_frequency)) { + dprint("Cannot retrieve max freq from cpufreq kernel " + "subsystem\n"); + return -1; + } + max_freq_mode = MAX_FREQ_SYSFS; + return 0; +} + +/* + * This monitor provides: + * + * 1) Average frequency a CPU resided in + * This always works if the CPU has aperf/mperf capabilities + * + * 2) C0 and Cx (any sleep state) time a CPU resided in + * Works if mperf timer stops ticking in sleep states which + * seem to be the case on all current HW. + * Both is directly retrieved from HW registers and is independent + * from kernel statistics. + */ +struct cpuidle_monitor mperf_monitor; +struct cpuidle_monitor *mperf_register(void) +{ + if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_APERF)) + return NULL; + + if (init_maxfreq_mode()) + return NULL; + + /* Free this at program termination */ + is_valid = calloc(cpu_count, sizeof(int)); + mperf_previous_count = calloc(cpu_count, sizeof(unsigned long long)); + aperf_previous_count = calloc(cpu_count, sizeof(unsigned long long)); + mperf_current_count = calloc(cpu_count, sizeof(unsigned long long)); + aperf_current_count = calloc(cpu_count, sizeof(unsigned long long)); + + mperf_monitor.name_len = strlen(mperf_monitor.name); + return &mperf_monitor; +} + +void mperf_unregister(void) +{ + free(mperf_previous_count); + free(aperf_previous_count); + free(mperf_current_count); + free(aperf_current_count); + free(is_valid); +} + +struct cpuidle_monitor mperf_monitor = { + .name = "Mperf", + .hw_states_num = MPERF_CSTATE_COUNT, + .hw_states = mperf_cstates, + .start = mperf_start, + .stop = mperf_stop, + .do_register = mperf_register, + .unregister = mperf_unregister, + .needs_root = 1, + .overflow_s = 922000000 /* 922337203 seconds TSC overflow + at 20GHz */ +}; +#endif /* #if defined(__i386__) || defined(__x86_64__) */ |