From fe9081cc9bdabb0be953a39ad977cea14e35bce5 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 8 Oct 2009 11:56:07 +0200 Subject: [PATCH] perf, x86: Add simple group validation Refuse to add events when the group wouldn't fit onto the PMU anymore. Naive implementation. Signed-off-by: Peter Zijlstra Cc: Stephane Eranian LKML-Reference: <1254911461.26976.239.camel@twins> Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event.c | 90 ++++++++++++++++++++++++-------- 1 file changed, 69 insertions(+), 21 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 9c758548a0e6..9961d845719d 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -114,7 +114,8 @@ struct x86_pmu { u64 intel_ctrl; void (*enable_bts)(u64 config); void (*disable_bts)(void); - int (*get_event_idx)(struct hw_perf_event *hwc); + int (*get_event_idx)(struct cpu_hw_events *cpuc, + struct hw_perf_event *hwc); }; static struct x86_pmu x86_pmu __read_mostly; @@ -523,7 +524,7 @@ static u64 intel_pmu_raw_event(u64 hw_event) #define CORE_EVNTSEL_UNIT_MASK 0x0000FF00ULL #define CORE_EVNTSEL_EDGE_MASK 0x00040000ULL #define CORE_EVNTSEL_INV_MASK 0x00800000ULL -#define CORE_EVNTSEL_REG_MASK 0xFF000000ULL +#define CORE_EVNTSEL_REG_MASK 0xFF000000ULL #define CORE_EVNTSEL_MASK \ (CORE_EVNTSEL_EVENT_MASK | \ @@ -1390,8 +1391,7 @@ static void amd_pmu_enable_event(struct hw_perf_event *hwc, int idx) x86_pmu_enable_event(hwc, idx); } -static int -fixed_mode_idx(struct perf_event *event, struct hw_perf_event *hwc) +static int fixed_mode_idx(struct hw_perf_event *hwc) { unsigned int hw_event; @@ -1424,9 +1424,9 @@ fixed_mode_idx(struct perf_event *event, struct hw_perf_event *hwc) /* * generic counter allocator: get next free counter */ -static int gen_get_event_idx(struct hw_perf_event *hwc) +static int +gen_get_event_idx(struct cpu_hw_events *cpuc, struct hw_perf_event *hwc) { - struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); int idx; idx = find_first_zero_bit(cpuc->used_mask, x86_pmu.num_events); @@ -1436,16 +1436,16 @@ static int gen_get_event_idx(struct hw_perf_event *hwc) /* * intel-specific counter allocator: check event constraints */ -static int intel_get_event_idx(struct hw_perf_event *hwc) +static int +intel_get_event_idx(struct cpu_hw_events *cpuc, struct hw_perf_event *hwc) { - struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); const struct event_constraint *event_constraint; int i, code; if (!event_constraint) goto skip; - code = hwc->config & 0xff; + code = hwc->config & CORE_EVNTSEL_EVENT_MASK; for_each_event_constraint(event_constraint, event_constraint) { if (code == event_constraint->code) { @@ -1457,26 +1457,22 @@ static int intel_get_event_idx(struct hw_perf_event *hwc) } } skip: - return gen_get_event_idx(hwc); + return gen_get_event_idx(cpuc, hwc); } -/* - * Find a PMC slot for the freshly enabled / scheduled in event: - */ -static int x86_pmu_enable(struct perf_event *event) +static int +x86_schedule_event(struct cpu_hw_events *cpuc, struct hw_perf_event *hwc) { - struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); - struct hw_perf_event *hwc = &event->hw; int idx; - idx = fixed_mode_idx(event, hwc); + idx = fixed_mode_idx(hwc); if (idx == X86_PMC_IDX_FIXED_BTS) { /* BTS is already occupied. */ if (test_and_set_bit(idx, cpuc->used_mask)) return -EAGAIN; hwc->config_base = 0; - hwc->event_base = 0; + hwc->event_base = 0; hwc->idx = idx; } else if (idx >= 0) { /* @@ -1499,17 +1495,33 @@ static int x86_pmu_enable(struct perf_event *event) /* Try to get the previous generic event again */ if (idx == -1 || test_and_set_bit(idx, cpuc->used_mask)) { try_generic: - idx = x86_pmu.get_event_idx(hwc); + idx = x86_pmu.get_event_idx(cpuc, hwc); if (idx == -1) return -EAGAIN; set_bit(idx, cpuc->used_mask); hwc->idx = idx; } - hwc->config_base = x86_pmu.eventsel; - hwc->event_base = x86_pmu.perfctr; + hwc->config_base = x86_pmu.eventsel; + hwc->event_base = x86_pmu.perfctr; } + return idx; +} + +/* + * Find a PMC slot for the freshly enabled / scheduled in event: + */ +static int x86_pmu_enable(struct perf_event *event) +{ + struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); + struct hw_perf_event *hwc = &event->hw; + int idx; + + idx = x86_schedule_event(cpuc, hwc); + if (idx < 0) + return idx; + perf_events_lapic_init(); x86_pmu.disable(hwc, idx); @@ -2212,11 +2224,47 @@ static const struct pmu pmu = { .unthrottle = x86_pmu_unthrottle, }; +static int +validate_event(struct cpu_hw_events *cpuc, struct perf_event *event) +{ + struct hw_perf_event fake_event = event->hw; + + if (event->pmu != &pmu) + return 0; + + return x86_schedule_event(cpuc, &fake_event); +} + +static int validate_group(struct perf_event *event) +{ + struct perf_event *sibling, *leader = event->group_leader; + struct cpu_hw_events fake_pmu; + + memset(&fake_pmu, 0, sizeof(fake_pmu)); + + if (!validate_event(&fake_pmu, leader)) + return -ENOSPC; + + list_for_each_entry(sibling, &leader->sibling_list, group_entry) { + if (!validate_event(&fake_pmu, sibling)) + return -ENOSPC; + } + + if (!validate_event(&fake_pmu, event)) + return -ENOSPC; + + return 0; +} + const struct pmu *hw_perf_event_init(struct perf_event *event) { int err; err = __hw_perf_event_init(event); + if (!err) { + if (event->group_leader != event) + err = validate_group(event); + } if (err) { if (event->destroy) event->destroy(event); -- 2.20.1