From 63b146490befc027a7e0923e333269e68b20d380 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 22 Jan 2010 16:32:17 +0100 Subject: [PATCH] perf_event: x86: Optimize the constraint searching bits Instead of copying bitmasks around, pass pointers to the constraint structure. Signed-off-by: Peter Zijlstra Cc: Stephane Eranian LKML-Reference: <20100122155535.887853503@chello.nl> Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event.c | 75 +++++++++++++++----------------- 1 file changed, 34 insertions(+), 41 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 4d1ed101c10d..092ad566734c 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -134,12 +134,14 @@ struct x86_pmu { u64 intel_ctrl; void (*enable_bts)(u64 config); void (*disable_bts)(void); - void (*get_event_constraints)(struct cpu_hw_events *cpuc, - struct perf_event *event, - unsigned long *idxmsk); + + struct event_constraint * + (*get_event_constraints)(struct cpu_hw_events *cpuc, + struct perf_event *event); + void (*put_event_constraints)(struct cpu_hw_events *cpuc, struct perf_event *event); - const struct event_constraint *event_constraints; + struct event_constraint *event_constraints; }; static struct x86_pmu x86_pmu __read_mostly; @@ -1242,17 +1244,15 @@ static int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign) { int i, j , w, num; int weight, wmax; - unsigned long *c; - unsigned long constraints[X86_PMC_IDX_MAX][BITS_TO_LONGS(X86_PMC_IDX_MAX)]; + struct event_constraint *c, *constraints[X86_PMC_IDX_MAX]; unsigned long used_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)]; struct hw_perf_event *hwc; bitmap_zero(used_mask, X86_PMC_IDX_MAX); for (i = 0; i < n; i++) { - x86_pmu.get_event_constraints(cpuc, - cpuc->event_list[i], - constraints[i]); + constraints[i] = + x86_pmu.get_event_constraints(cpuc, cpuc->event_list[i]); } /* @@ -1267,7 +1267,7 @@ static int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign) break; /* constraint still honored */ - if (!test_bit(hwc->idx, c)) + if (!test_bit(hwc->idx, c->idxmsk)) break; /* not already used */ @@ -1320,11 +1320,11 @@ static int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign) c = constraints[i]; hwc = &cpuc->event_list[i]->hw; - weight = bitmap_weight(c, X86_PMC_IDX_MAX); + weight = bitmap_weight(c->idxmsk, X86_PMC_IDX_MAX); if (weight != w) continue; - for_each_bit(j, c, X86_PMC_IDX_MAX) { + for_each_bit(j, c->idxmsk, X86_PMC_IDX_MAX) { if (!test_bit(j, used_mask)) break; } @@ -2155,11 +2155,13 @@ perf_event_nmi_handler(struct notifier_block *self, return NOTIFY_STOP; } +static struct event_constraint unconstrained; + static struct event_constraint bts_constraint = EVENT_CONSTRAINT(0, 1ULL << X86_PMC_IDX_FIXED_BTS, 0); -static int intel_special_constraints(struct perf_event *event, - unsigned long *idxmsk) +static struct event_constraint * +intel_special_constraints(struct perf_event *event) { unsigned int hw_event; @@ -2169,46 +2171,34 @@ static int intel_special_constraints(struct perf_event *event, x86_pmu.event_map(PERF_COUNT_HW_BRANCH_INSTRUCTIONS)) && (event->hw.sample_period == 1))) { - bitmap_copy((unsigned long *)idxmsk, - (unsigned long *)bts_constraint.idxmsk, - X86_PMC_IDX_MAX); - return 1; + return &bts_constraint; } - return 0; + return NULL; } -static void intel_get_event_constraints(struct cpu_hw_events *cpuc, - struct perf_event *event, - unsigned long *idxmsk) +static struct event_constraint * +intel_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event) { - const struct event_constraint *c; + struct event_constraint *c; - /* - * cleanup bitmask - */ - bitmap_zero(idxmsk, X86_PMC_IDX_MAX); - - if (intel_special_constraints(event, idxmsk)) - return; + c = intel_special_constraints(event); + if (c) + return c; if (x86_pmu.event_constraints) { for_each_event_constraint(c, x86_pmu.event_constraints) { - if ((event->hw.config & c->cmask) == c->code) { - bitmap_copy(idxmsk, c->idxmsk, X86_PMC_IDX_MAX); - return; - } + if ((event->hw.config & c->cmask) == c->code) + return c; } } - /* no constraints, means supports all generic counters */ - bitmap_fill((unsigned long *)idxmsk, x86_pmu.num_events); + + return &unconstrained; } -static void amd_get_event_constraints(struct cpu_hw_events *cpuc, - struct perf_event *event, - unsigned long *idxmsk) +static struct event_constraint * +amd_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event) { - /* no constraints, means supports all generic counters */ - bitmap_fill(idxmsk, x86_pmu.num_events); + return &unconstrained; } static int x86_event_sched_in(struct perf_event *event, @@ -2576,6 +2566,9 @@ void __init init_hw_perf_events(void) perf_events_lapic_init(); register_die_notifier(&perf_event_nmi_notifier); + unconstrained = (struct event_constraint) + EVENT_CONSTRAINT(0, (1ULL << x86_pmu.num_events) - 1, 0); + pr_info("... version: %d\n", x86_pmu.version); pr_info("... bit width: %d\n", x86_pmu.event_bits); pr_info("... generic registers: %d\n", x86_pmu.num_events); -- 2.20.1