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x86, perfcounters: refactor code for fixed-function PMCs
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Impact: clean up

Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Ingo Molnar committed Dec 23, 2008
1 parent 703e937 commit 862a1a5
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Showing 2 changed files with 52 additions and 35 deletions.
14 changes: 13 additions & 1 deletion arch/x86/include/asm/perf_counter.h
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,10 @@
#define X86_PMC_MAX_GENERIC 8
#define X86_PMC_MAX_FIXED 3

#define X86_PMC_IDX_GENERIC 0
#define X86_PMC_IDX_FIXED 32
#define X86_PMC_IDX_MAX 64

#define MSR_ARCH_PERFMON_PERFCTR0 0xc1
#define MSR_ARCH_PERFMON_PERFCTR1 0xc2

Expand Down Expand Up @@ -54,6 +58,15 @@ union cpuid10_edx {
* Fixed-purpose performance counters:
*/

/*
* All 3 fixed-mode PMCs are configured via this single MSR:
*/
#define MSR_ARCH_PERFMON_FIXED_CTR_CTRL 0x38d

/*
* The counts are available in three separate MSRs:
*/

/* Instr_Retired.Any: */
#define MSR_ARCH_PERFMON_FIXED_CTR0 0x309

Expand All @@ -63,7 +76,6 @@ union cpuid10_edx {
/* 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);
Expand Down
73 changes: 39 additions & 34 deletions arch/x86/kernel/cpu/perf_counter.c
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Original file line number Diff line number Diff line change
Expand Up @@ -24,17 +24,14 @@ static bool perf_counters_initialized __read_mostly;
/*
* Number of (generic) HW counters:
*/
static int nr_hw_counters __read_mostly;
static u32 perf_counter_mask __read_mostly;
static int nr_counters_generic __read_mostly;
static u64 perf_counter_mask __read_mostly;

static int nr_hw_counters_fixed __read_mostly;
static int nr_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)];

struct perf_counter *fixed[X86_PMC_MAX_FIXED];
unsigned long used_fixed[BITS_TO_LONGS(X86_PMC_MAX_FIXED)];
struct perf_counter *counters[X86_PMC_IDX_MAX];
unsigned long used[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
};

/*
Expand Down Expand Up @@ -159,7 +156,7 @@ void hw_perf_enable_all(void)
if (unlikely(!perf_counters_initialized))
return;

wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, perf_counter_mask, 0);
wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, perf_counter_mask);
}

u64 hw_perf_save_disable(void)
Expand All @@ -170,7 +167,7 @@ u64 hw_perf_save_disable(void)
return 0;

rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, ctrl);
wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0, 0);
wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0);

return ctrl;
}
Expand All @@ -181,7 +178,7 @@ void hw_perf_restore(u64 ctrl)
if (unlikely(!perf_counters_initialized))
return;

wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, ctrl, 0);
wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, ctrl);
}
EXPORT_SYMBOL_GPL(hw_perf_restore);

Expand Down Expand Up @@ -239,6 +236,11 @@ __pmc_generic_enable(struct perf_counter *counter,
hwc->config | ARCH_PERFMON_EVENTSEL0_ENABLE, 0);
}

static int fixed_mode_idx(struct hw_perf_counter *hwc)
{
return -1;
}

/*
* Find a PMC slot for the freshly enabled / scheduled in counter:
*/
Expand All @@ -250,7 +252,7 @@ static void pmc_generic_enable(struct perf_counter *counter)

/* Try to get the previous counter again */
if (test_and_set_bit(idx, cpuc->used)) {
idx = find_first_zero_bit(cpuc->used, nr_hw_counters);
idx = find_first_zero_bit(cpuc->used, nr_counters_generic);
set_bit(idx, cpuc->used);
hwc->idx = idx;
}
Expand All @@ -259,7 +261,7 @@ static void pmc_generic_enable(struct perf_counter *counter)

__pmc_generic_disable(counter, hwc, idx);

cpuc->generic[idx] = counter;
cpuc->counters[idx] = counter;

__hw_perf_counter_set_period(counter, hwc, idx);
__pmc_generic_enable(counter, hwc, idx);
Expand All @@ -270,7 +272,7 @@ void perf_counter_print_debug(void)
u64 ctrl, status, overflow, pmc_ctrl, pmc_count, prev_left;
int cpu, idx;

if (!nr_hw_counters)
if (!nr_counters_generic)
return;

local_irq_disable();
Expand All @@ -286,7 +288,7 @@ void perf_counter_print_debug(void)
printk(KERN_INFO "CPU#%d: status: %016llx\n", cpu, status);
printk(KERN_INFO "CPU#%d: overflow: %016llx\n", cpu, overflow);

for (idx = 0; idx < nr_hw_counters; idx++) {
for (idx = 0; idx < nr_counters_generic; idx++) {
rdmsrl(MSR_ARCH_PERFMON_EVENTSEL0 + idx, pmc_ctrl);
rdmsrl(MSR_ARCH_PERFMON_PERFCTR0 + idx, pmc_count);

Expand All @@ -311,7 +313,7 @@ static void pmc_generic_disable(struct perf_counter *counter)
__pmc_generic_disable(counter, hwc, idx);

clear_bit(idx, cpuc->used);
cpuc->generic[idx] = NULL;
cpuc->counters[idx] = NULL;

/*
* Drain the remaining delta count out of a counter
Expand Down Expand Up @@ -381,7 +383,7 @@ static void __smp_perf_counter_interrupt(struct pt_regs *regs, int nmi)
rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, saved_global);

/* Disable counters globally */
wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0, 0);
wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0);
ack_APIC_irq();

cpuc = &per_cpu(cpu_hw_counters, cpu);
Expand All @@ -392,8 +394,8 @@ static void __smp_perf_counter_interrupt(struct pt_regs *regs, int nmi)

again:
ack = status;
for_each_bit(bit, (unsigned long *) &status, nr_hw_counters) {
struct perf_counter *counter = cpuc->generic[bit];
for_each_bit(bit, (unsigned long *) &status, nr_counters_generic) {
struct perf_counter *counter = cpuc->counters[bit];

clear_bit(bit, (unsigned long *) &status);
if (!counter)
Expand Down Expand Up @@ -424,7 +426,7 @@ static void __smp_perf_counter_interrupt(struct pt_regs *regs, int nmi)
}
}

wrmsr(MSR_CORE_PERF_GLOBAL_OVF_CTRL, ack, 0);
wrmsrl(MSR_CORE_PERF_GLOBAL_OVF_CTRL, ack);

/*
* Repeat if there is more work to be done:
Expand All @@ -436,7 +438,7 @@ static void __smp_perf_counter_interrupt(struct pt_regs *regs, int nmi)
/*
* Restore - do not reenable when global enable is off:
*/
wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, saved_global, 0);
wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, saved_global);
}

void smp_perf_counter_interrupt(struct pt_regs *regs)
Expand All @@ -462,8 +464,8 @@ void perf_counter_notify(struct pt_regs *regs)
cpu = smp_processor_id();
cpuc = &per_cpu(cpu_hw_counters, cpu);

for_each_bit(bit, cpuc->used, nr_hw_counters) {
struct perf_counter *counter = cpuc->generic[bit];
for_each_bit(bit, cpuc->used, X86_PMC_IDX_MAX) {
struct perf_counter *counter = cpuc->counters[bit];

if (!counter)
continue;
Expand Down Expand Up @@ -540,26 +542,29 @@ void __init init_hw_perf_counters(void)

printk(KERN_INFO "... version: %d\n", eax.split.version_id);
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;
nr_counters_generic = eax.split.num_counters;
if (nr_counters_generic > X86_PMC_MAX_GENERIC) {
nr_counters_generic = X86_PMC_MAX_GENERIC;
WARN(1, KERN_ERR "hw perf counters %d > max(%d), clipping!",
nr_hw_counters, X86_PMC_MAX_GENERIC);
nr_counters_generic, X86_PMC_MAX_GENERIC);
}
perf_counter_mask = (1 << nr_hw_counters) - 1;
perf_max_counters = nr_hw_counters;
perf_counter_mask = (1 << nr_counters_generic) - 1;
perf_max_counters = nr_counters_generic;

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;
nr_counters_fixed = edx.split.num_counters_fixed;
if (nr_counters_fixed > X86_PMC_MAX_FIXED) {
nr_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);
nr_counters_fixed, X86_PMC_MAX_FIXED);
}
printk(KERN_INFO "... fixed counters: %d\n", nr_hw_counters_fixed);
printk(KERN_INFO "... fixed counters: %d\n", nr_counters_fixed);

perf_counter_mask |= ((1LL << nr_counters_fixed)-1) << X86_PMC_IDX_FIXED;

printk(KERN_INFO "... counter mask: %016Lx\n", perf_counter_mask);
perf_counters_initialized = true;

perf_counters_lapic_init(0);
Expand Down

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