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Commit 703e937c authored by Ingo Molnar's avatar Ingo Molnar
Browse files

perfcounters: add fixed-mode PMC enumeration 



Enumerate fixed-mode PMCs based on CPUID, and feed that into the
perfcounter code.

Does not use fixed-mode PMCs yet.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent eb2b8618

arch/x86/include/asm/perf_counter.h

+23 −0
Original line number Diff line number Diff line
@@ -41,6 +41,29 @@ union cpuid10_eax { 
	unsigned int full;

};



union cpuid10_edx {

	struct {

		unsigned int num_counters_fixed:4;

		unsigned int reserved:28;

	} split;

	unsigned int full;

};





/*

 * Fixed-purpose performance counters:

 */



/* Instr_Retired.Any: */

#define MSR_ARCH_PERFMON_FIXED_CTR0			0x309



/* CPU_CLK_Unhalted.Core: */

#define MSR_ARCH_PERFMON_FIXED_CTR1			0x30a



/* CPU_CLK_Unhalted.Ref: */

#define MSR_ARCH_PERFMON_FIXED_CTR2			0x30b





#ifdef CONFIG_PERF_COUNTERS

extern void init_hw_perf_counters(void);

extern void perf_counters_lapic_init(int nmi);

arch/x86/kernel/cpu/perf_counter.c

+17 −6
Original line number Diff line number Diff line
@@ -27,6 +27,8 @@ static bool perf_counters_initialized __read_mostly; 
static int nr_hw_counters __read_mostly;

static u32 perf_counter_mask __read_mostly;



static int nr_hw_counters_fixed __read_mostly;



struct cpu_hw_counters {

	struct perf_counter	*generic[X86_PMC_MAX_GENERIC];

	unsigned long		used[BITS_TO_LONGS(X86_PMC_MAX_GENERIC)];
@@ -519,8 +521,9 @@ static __read_mostly struct notifier_block perf_counter_nmi_notifier = { 
void __init init_hw_perf_counters(void)

{

	union cpuid10_eax eax;

	unsigned int unused;

	unsigned int ebx;

	unsigned int unused;

	union cpuid10_edx edx;



	if (!cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON))

		return;
@@ -529,14 +532,14 @@ void __init init_hw_perf_counters(void) 
	 * Check whether the Architectural PerfMon supports

	 * Branch Misses Retired Event or not.

	 */

	cpuid(10, &(eax.full), &ebx, &unused, &unused);

	cpuid(10, &eax.full, &ebx, &unused, &edx.full);

	if (eax.split.mask_length <= ARCH_PERFMON_BRANCH_MISSES_RETIRED)

		return;



	printk(KERN_INFO "Intel Performance Monitoring support detected.\n");



	printk(KERN_INFO "... version:         %d\n", eax.split.version_id);

	printk(KERN_INFO "... num_counters: %d\n", eax.split.num_counters);

	printk(KERN_INFO "... num counters:    %d\n", eax.split.num_counters);

	nr_hw_counters = eax.split.num_counters;

	if (nr_hw_counters > X86_PMC_MAX_GENERIC) {

		nr_hw_counters = X86_PMC_MAX_GENERIC;
@@ -546,8 +549,16 @@ void __init init_hw_perf_counters(void) 
	perf_counter_mask = (1 << nr_hw_counters) - 1;

	perf_max_counters = nr_hw_counters;



	printk(KERN_INFO "... bit_width:    %d\n", eax.split.bit_width);

	printk(KERN_INFO "... mask_length:  %d\n", eax.split.mask_length);

	printk(KERN_INFO "... bit width:       %d\n", eax.split.bit_width);

	printk(KERN_INFO "... mask length:     %d\n", eax.split.mask_length);



	nr_hw_counters_fixed = edx.split.num_counters_fixed;

	if (nr_hw_counters_fixed > X86_PMC_MAX_FIXED) {

		nr_hw_counters_fixed = X86_PMC_MAX_FIXED;

		WARN(1, KERN_ERR "hw perf counters fixed %d > max(%d), clipping!",

			nr_hw_counters_fixed, X86_PMC_MAX_FIXED);

	}

	printk(KERN_INFO "... fixed counters:  %d\n", nr_hw_counters_fixed);



	perf_counters_initialized = true;