diff options
Diffstat (limited to 'arch/x86/kernel/cpu/perf_event_intel.c')
-rw-r--r-- | arch/x86/kernel/cpu/perf_event_intel.c | 96 |
1 files changed, 72 insertions, 24 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c index 214ac860ebe0..ee05c90012d2 100644 --- a/arch/x86/kernel/cpu/perf_event_intel.c +++ b/arch/x86/kernel/cpu/perf_event_intel.c @@ -491,33 +491,78 @@ static void intel_pmu_enable_all(int added) * Intel Errata AAP53 (model 30) * Intel Errata BD53 (model 44) * - * These chips need to be 'reset' when adding counters by programming - * the magic three (non counting) events 0x4300D2, 0x4300B1 and 0x4300B5 - * either in sequence on the same PMC or on different PMCs. + * The official story: + * These chips need to be 'reset' when adding counters by programming the + * magic three (non-counting) events 0x4300B5, 0x4300D2, and 0x4300B1 either + * in sequence on the same PMC or on different PMCs. + * + * In practise it appears some of these events do in fact count, and + * we need to programm all 4 events. */ -static void intel_pmu_nhm_enable_all(int added) +static void intel_pmu_nhm_workaround(void) { - if (added) { - struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); - int i; + struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); + static const unsigned long nhm_magic[4] = { + 0x4300B5, + 0x4300D2, + 0x4300B1, + 0x4300B1 + }; + struct perf_event *event; + int i; + + /* + * The Errata requires below steps: + * 1) Clear MSR_IA32_PEBS_ENABLE and MSR_CORE_PERF_GLOBAL_CTRL; + * 2) Configure 4 PERFEVTSELx with the magic events and clear + * the corresponding PMCx; + * 3) set bit0~bit3 of MSR_CORE_PERF_GLOBAL_CTRL; + * 4) Clear MSR_CORE_PERF_GLOBAL_CTRL; + * 5) Clear 4 pairs of ERFEVTSELx and PMCx; + */ - wrmsrl(MSR_ARCH_PERFMON_EVENTSEL0 + 0, 0x4300D2); - wrmsrl(MSR_ARCH_PERFMON_EVENTSEL0 + 1, 0x4300B1); - wrmsrl(MSR_ARCH_PERFMON_EVENTSEL0 + 2, 0x4300B5); + /* + * The real steps we choose are a little different from above. + * A) To reduce MSR operations, we don't run step 1) as they + * are already cleared before this function is called; + * B) Call x86_perf_event_update to save PMCx before configuring + * PERFEVTSELx with magic number; + * C) With step 5), we do clear only when the PERFEVTSELx is + * not used currently. + * D) Call x86_perf_event_set_period to restore PMCx; + */ + + /* We always operate 4 pairs of PERF Counters */ + for (i = 0; i < 4; i++) { + event = cpuc->events[i]; + if (event) + x86_perf_event_update(event); + } - wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0x3); - wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0x0); + for (i = 0; i < 4; i++) { + wrmsrl(MSR_ARCH_PERFMON_EVENTSEL0 + i, nhm_magic[i]); + wrmsrl(MSR_ARCH_PERFMON_PERFCTR0 + i, 0x0); + } - for (i = 0; i < 3; i++) { - struct perf_event *event = cpuc->events[i]; + wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0xf); + wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0x0); - if (!event) - continue; + for (i = 0; i < 4; i++) { + event = cpuc->events[i]; + if (event) { + x86_perf_event_set_period(event); __x86_pmu_enable_event(&event->hw, - ARCH_PERFMON_EVENTSEL_ENABLE); - } + ARCH_PERFMON_EVENTSEL_ENABLE); + } else + wrmsrl(MSR_ARCH_PERFMON_EVENTSEL0 + i, 0x0); } +} + +static void intel_pmu_nhm_enable_all(int added) +{ + if (added) + intel_pmu_nhm_workaround(); intel_pmu_enable_all(added); } @@ -667,7 +712,8 @@ static int intel_pmu_handle_irq(struct pt_regs *regs) struct perf_sample_data data; struct cpu_hw_events *cpuc; int bit, loops; - u64 ack, status; + u64 status; + int handled = 0; perf_sample_data_init(&data, 0); @@ -683,6 +729,7 @@ static int intel_pmu_handle_irq(struct pt_regs *regs) loops = 0; again: + intel_pmu_ack_status(status); if (++loops > 100) { WARN_ONCE(1, "perfevents: irq loop stuck!\n"); perf_event_print_debug(); @@ -691,19 +738,22 @@ again: } inc_irq_stat(apic_perf_irqs); - ack = status; intel_pmu_lbr_read(); /* * PEBS overflow sets bit 62 in the global status register */ - if (__test_and_clear_bit(62, (unsigned long *)&status)) + if (__test_and_clear_bit(62, (unsigned long *)&status)) { + handled++; x86_pmu.drain_pebs(regs); + } for_each_set_bit(bit, (unsigned long *)&status, X86_PMC_IDX_MAX) { struct perf_event *event = cpuc->events[bit]; + handled++; + if (!test_bit(bit, cpuc->active_mask)) continue; @@ -716,8 +766,6 @@ again: x86_pmu_stop(event); } - intel_pmu_ack_status(ack); - /* * Repeat if there is more work to be done: */ @@ -727,7 +775,7 @@ again: done: intel_pmu_enable_all(0); - return 1; + return handled; } static struct event_constraint * |