From 962bf7a66edca4d36a730a38ff8410a67f560e40 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 13 May 2009 13:21:36 +0200 Subject: [PATCH] perf_counter: x86: Fix up the amd NMI/INT throttle perf_counter_unthrottle() restores throttle_ctrl, buts its never set. Also, we fail to disable all counters when throttling. [ Impact: fix rare stuck perf-counters when they are throttled ] Signed-off-by: Peter Zijlstra Cc: Paul Mackerras Cc: Corey Ashford LKML-Reference: Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_counter.c | 38 ++++++++++++++++++++++++++------------ 1 file changed, 26 insertions(+), 12 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c index c19e927..7601c01 100644 --- a/arch/x86/kernel/cpu/perf_counter.c +++ b/arch/x86/kernel/cpu/perf_counter.c @@ -334,6 +334,8 @@ static u64 amd_pmu_save_disable_all(void) * right thing. */ barrier(); + if (!enabled) + goto out; for (idx = 0; idx < x86_pmu.num_counters; idx++) { u64 val; @@ -347,6 +349,7 @@ static u64 amd_pmu_save_disable_all(void) wrmsrl(MSR_K7_EVNTSEL0 + idx, val); } +out: return enabled; } @@ -787,32 +790,43 @@ static int amd_pmu_handle_irq(struct pt_regs *regs, int nmi) int handled = 0; struct perf_counter *counter; struct hw_perf_counter *hwc; - int idx; + int idx, throttle = 0; + + cpuc->throttle_ctrl = cpuc->enabled; + cpuc->enabled = 0; + barrier(); + + if (cpuc->throttle_ctrl) { + if (++cpuc->interrupts >= PERFMON_MAX_INTERRUPTS) + throttle = 1; + } - ++cpuc->interrupts; for (idx = 0; idx < x86_pmu.num_counters; idx++) { + int disable = 0; + if (!test_bit(idx, cpuc->active_mask)) continue; + counter = cpuc->counters[idx]; hwc = &counter->hw; val = x86_perf_counter_update(counter, hwc, idx); if (val & (1ULL << (x86_pmu.counter_bits - 1))) - continue; + goto next; + /* counter overflow */ x86_perf_counter_set_period(counter, hwc, idx); handled = 1; inc_irq_stat(apic_perf_irqs); - if (perf_counter_overflow(counter, nmi, regs, 0)) - amd_pmu_disable_counter(hwc, idx); - else if (cpuc->interrupts >= PERFMON_MAX_INTERRUPTS) - /* - * do not reenable when throttled, but reload - * the register - */ + disable = perf_counter_overflow(counter, nmi, regs, 0); + +next: + if (disable || throttle) amd_pmu_disable_counter(hwc, idx); - else if (counter->state == PERF_COUNTER_STATE_ACTIVE) - amd_pmu_enable_counter(hwc, idx); } + + if (cpuc->throttle_ctrl && !throttle) + cpuc->enabled = 1; + return handled; } -- 2.7.4