From 75c7003fbf419f05215d4ca09bf3964d0b1c99e9 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 22 Feb 2016 22:19:22 +0000 Subject: [PATCH] perf/x86/intel/rapl: Calculate timing once No point in doing the same calculation over and over. Do it once in rapl_check_hw_unit(). Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Cc: Andi Kleen Cc: Arnaldo Carvalho de Melo Cc: Borislav Petkov Cc: Harish Chegondi Cc: Jacob Pan Cc: Jiri Olsa Cc: Kan Liang Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Vince Weaver Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/20160222221012.409238136@linutronix.de Signed-off-by: Ingo Molnar --- arch/x86/events/intel/rapl.c | 39 +++++++++++++++++------------------- 1 file changed, 18 insertions(+), 21 deletions(-) diff --git a/arch/x86/events/intel/rapl.c b/arch/x86/events/intel/rapl.c index 976558a5f5d4..b1d4a2f1feeb 100644 --- a/arch/x86/events/intel/rapl.c +++ b/arch/x86/events/intel/rapl.c @@ -129,6 +129,7 @@ static int rapl_hw_unit[NR_RAPL_DOMAINS] __read_mostly; /* 1/2^hw_unit Joule */ static struct pmu rapl_pmu_class; static cpumask_t rapl_cpu_mask; static int rapl_cntr_mask; +static u64 rapl_timer_ms; static DEFINE_PER_CPU(struct rapl_pmu *, rapl_pmu); static DEFINE_PER_CPU(struct rapl_pmu *, rapl_pmu_to_free); @@ -558,7 +559,6 @@ static int rapl_cpu_prepare(int cpu) { struct rapl_pmu *pmu = per_cpu(rapl_pmu, cpu); int phys_id = topology_physical_package_id(cpu); - u64 ms; if (pmu) return 0; @@ -575,19 +575,7 @@ static int rapl_cpu_prepare(int cpu) pmu->pmu = &rapl_pmu_class; - /* - * use reference of 200W for scaling the timeout - * to avoid missing counter overflows. - * 200W = 200 Joules/sec - * divide interval by 2 to avoid lockstep (2 * 100) - * if hw unit is 32, then we use 2 ms 1/200/2 - */ - if (rapl_hw_unit[0] < 32) - ms = (1000 / (2 * 100)) * (1ULL << (32 - rapl_hw_unit[0] - 1)); - else - ms = 2; - - pmu->timer_interval = ms_to_ktime(ms); + pmu->timer_interval = ms_to_ktime(rapl_timer_ms); rapl_hrtimer_init(pmu); @@ -676,6 +664,19 @@ static int rapl_check_hw_unit(void (*quirk)(void)) /* Apply cpu model quirk */ if (quirk) quirk(); + + /* + * Calculate the timer rate: + * Use reference of 200W for scaling the timeout to avoid counter + * overflows. 200W = 200 Joules/sec + * Divide interval by 2 to avoid lockstep (2 * 100) + * if hw unit is 32, then we use 2 ms 1/200/2 + */ + rapl_timer_ms = 2; + if (rapl_hw_unit[0] < 32) { + rapl_timer_ms = (1000 / (2 * 100)); + rapl_timer_ms *= (1ULL << (32 - rapl_hw_unit[0] - 1)); + } return 0; } @@ -695,9 +696,7 @@ static const struct x86_cpu_id rapl_cpu_match[] = { static int __init rapl_pmu_init(void) { void (*quirk)(void) = NULL; - struct rapl_pmu *pmu; - int cpu, ret; - int i; + int cpu, ret, i; /* * check for Intel processor family 6 @@ -758,15 +757,14 @@ static int __init rapl_pmu_init(void) } __perf_cpu_notifier(rapl_cpu_notifier); - - pmu = __this_cpu_read(rapl_pmu); + cpu_notifier_register_done(); pr_info("RAPL PMU detected," " API unit is 2^-32 Joules," " %d fixed counters" " %llu ms ovfl timer\n", hweight32(rapl_cntr_mask), - ktime_to_ms(pmu->timer_interval)); + rapl_timer_ms); for (i = 0; i < NR_RAPL_DOMAINS; i++) { if (rapl_cntr_mask & (1 << i)) { pr_info("hw unit of domain %s 2^-%d Joules\n", @@ -774,7 +772,6 @@ static int __init rapl_pmu_init(void) } } - cpu_notifier_register_done(); return 0; out: -- 2.20.1