From 21ed5574d1622118b49b0c6342acc8d27d0799be Mon Sep 17 00:00:00 2001 From: Len Brown Date: Mon, 19 Oct 2015 22:37:40 -0400 Subject: tools/power turbostat: simplify Bzy_MHz calculation Bzy_MHz = TSC_delta*tsc_tweak/APERF_delta/MPERF_delta/measurement_interval becomes Bzy_MHz = base_mhz/APERF_delta/MPERF_delta on systems which support MSR_NHM_PLATFORM_INFO. base_mhz is calculated directly from the base_ratio reported in MSR_NHM_PLATFORM_INFO * bclk, and bclk is discovered via MSR or cpuid. This reduces the dependency of Bzy_MHz calculation on the TSC. Previously, there were 4 TSC readings required in each caculation, the raw TSC delta combined with the measurement_interval. This also removes the "tsc_tweak" correction factor used when TSC runs on a different base clock from the CPU's bclk. After this change, tsc_tweak is used only for %Busy. The end-result should be a Bzy_MHz result slightly less prone to jitter. Signed-off-by: Len Brown --- tools/power/x86/turbostat/turbostat.c | 28 +++++++++++++++++----------- 1 file changed, 17 insertions(+), 11 deletions(-) (limited to 'tools/power') diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c index bde0ef1a63df..84ec4e459975 100644 --- a/tools/power/x86/turbostat/turbostat.c +++ b/tools/power/x86/turbostat/turbostat.c @@ -75,6 +75,7 @@ unsigned int aperf_mperf_multiplier = 1; int do_smi; double bclk; double base_hz; +unsigned int has_base_hz; double tsc_tweak = 1.0; unsigned int show_pkg; unsigned int show_core; @@ -96,6 +97,7 @@ unsigned int do_ring_perf_limit_reasons; unsigned int crystal_hz; unsigned long long tsc_hz; int base_cpu; +double discover_bclk(unsigned int family, unsigned int model); #define RAPL_PKG (1 << 0) /* 0x610 MSR_PKG_POWER_LIMIT */ @@ -511,9 +513,13 @@ int format_counters(struct thread_data *t, struct core_data *c, } /* Bzy_MHz */ - if (has_aperf) - outp += sprintf(outp, "%8.0f", - 1.0 * t->tsc * tsc_tweak / units * t->aperf / t->mperf / interval_float); + if (has_aperf) { + if (has_base_hz) + outp += sprintf(outp, "%8.0f", base_hz / units * t->aperf / t->mperf); + else + outp += sprintf(outp, "%8.0f", + 1.0 * t->tsc / units * t->aperf / t->mperf / interval_float); + } /* TSC_MHz */ outp += sprintf(outp, "%8.0f", 1.0 * t->tsc/units/interval_float); @@ -1158,12 +1164,6 @@ int phi_pkg_cstate_limits[16] = {PCL__0, PCL__2, PCL_6N, PCL_6R, PCLRSV, PCLRSV, static void calculate_tsc_tweak() { - unsigned long long msr; - unsigned int base_ratio; - - get_msr(base_cpu, MSR_NHM_PLATFORM_INFO, &msr); - base_ratio = (msr >> 8) & 0xFF; - base_hz = base_ratio * bclk * 1000000; tsc_tweak = base_hz / tsc_hz; } @@ -1821,6 +1821,7 @@ void check_permissions() int probe_nhm_msrs(unsigned int family, unsigned int model) { unsigned long long msr; + unsigned int base_ratio; int *pkg_cstate_limits; if (!genuine_intel) @@ -1829,6 +1830,8 @@ int probe_nhm_msrs(unsigned int family, unsigned int model) if (family != 6) return 0; + bclk = discover_bclk(family, model); + switch (model) { case 0x1A: /* Core i7, Xeon 5500 series - Bloomfield, Gainstown NHM-EP */ case 0x1E: /* Core i7 and i5 Processor - Clarksfield, Lynnfield, Jasper Forest */ @@ -1871,9 +1874,13 @@ int probe_nhm_msrs(unsigned int family, unsigned int model) return 0; } get_msr(base_cpu, MSR_NHM_SNB_PKG_CST_CFG_CTL, &msr); - pkg_cstate_limit = pkg_cstate_limits[msr & 0xF]; + get_msr(base_cpu, MSR_NHM_PLATFORM_INFO, &msr); + base_ratio = (msr >> 8) & 0xFF; + + base_hz = base_ratio * bclk * 1000000; + has_base_hz = 1; return 1; } int has_nhm_turbo_ratio_limit(unsigned int family, unsigned int model) @@ -2780,7 +2787,6 @@ void process_cpuid() do_skl_residency = has_skl_msrs(family, model); do_slm_cstates = is_slm(family, model); do_knl_cstates = is_knl(family, model); - bclk = discover_bclk(family, model); rapl_probe(family, model); perf_limit_reasons_probe(family, model); -- cgit v1.2.3