diff options
Diffstat (limited to 'arch/x86/kernel/cpu/perf_counter.c')
| -rw-r--r-- | arch/x86/kernel/cpu/perf_counter.c | 38 |
1 files changed, 32 insertions, 6 deletions
diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c index 9376771f757..1a040b179b5 100644 --- a/arch/x86/kernel/cpu/perf_counter.c +++ b/arch/x86/kernel/cpu/perf_counter.c @@ -33,6 +33,9 @@ static int nr_counters_fixed __read_mostly; struct cpu_hw_counters { struct perf_counter *counters[X86_PMC_IDX_MAX]; unsigned long used[BITS_TO_LONGS(X86_PMC_IDX_MAX)]; + u64 last_interrupt; + u64 global_enable; + int throttled; }; /* @@ -474,16 +477,19 @@ perf_handle_group(struct perf_counter *sibling, u64 *status, u64 *overflown) static void __smp_perf_counter_interrupt(struct pt_regs *regs, int nmi) { int bit, cpu = smp_processor_id(); - u64 ack, status, saved_global; - struct cpu_hw_counters *cpuc; + u64 ack, status, now; + struct cpu_hw_counters *cpuc = &per_cpu(cpu_hw_counters, cpu); - rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, saved_global); + rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, cpuc->global_enable); /* Disable counters globally */ wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0); ack_APIC_irq(); - cpuc = &per_cpu(cpu_hw_counters, cpu); + now = sched_clock(); + if (now - cpuc->last_interrupt < PERFMON_MIN_PERIOD_NS) + cpuc->throttled = 1; + cpuc->last_interrupt = now; rdmsrl(MSR_CORE_PERF_GLOBAL_STATUS, status); if (!status) @@ -533,9 +539,29 @@ again: goto again; out: /* - * Restore - do not reenable when global enable is off: + * Restore - do not reenable when global enable is off or throttled: */ - wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, saved_global); + if (!cpuc->throttled) + wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, cpuc->global_enable); +} + +void perf_counter_unthrottle(void) +{ + struct cpu_hw_counters *cpuc; + + if (!cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON)) + return; + + if (unlikely(!perf_counters_initialized)) + return; + + cpuc = &per_cpu(cpu_hw_counters, smp_processor_id()); + if (cpuc->throttled) { + if (printk_ratelimit()) + printk(KERN_WARNING "PERFMON: max event frequency exceeded!\n"); + wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, cpuc->global_enable); + cpuc->throttled = 0; + } } void smp_perf_counter_interrupt(struct pt_regs *regs) |