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Commit 75c7003f authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
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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: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Harish Chegondi <harish.chegondi@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20160222221012.409238136@linutronix.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent b8b3319a

arch/x86/events/intel/rapl.c

+18 −21
Original line number Diff line number Diff line
@@ -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: