From 7c9903c9bf716d89b34f96cc2ed64e28dabf570b Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 18 Aug 2020 15:57:53 +0200 Subject: x86/perf, static_call: Optimize x86_pmu methods Replace many of the indirect calls with static_call(). The average PMI time, as measured by perf_sample_event_took()*: PRE: 3283.03 [ns] POST: 3145.12 [ns] Which is a ~138 [ns] win per PMI, or a ~4.2% decrease. [*] on an IVB-EP, using: 'perf record -a -e cycles -- make O=defconfig-build/ -j80' Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Cc: Linus Torvalds Link: https://lore.kernel.org/r/20200818135805.338001015@infradead.org --- arch/x86/events/core.c | 134 ++++++++++++++++++++++++++++++++++--------------- 1 file changed, 94 insertions(+), 40 deletions(-) (limited to 'arch/x86/events') diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 1cbf57dc2ac8..360c395d51d0 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -28,6 +28,7 @@ #include #include #include +#include #include #include @@ -52,6 +53,34 @@ DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = { DEFINE_STATIC_KEY_FALSE(rdpmc_never_available_key); DEFINE_STATIC_KEY_FALSE(rdpmc_always_available_key); +/* + * This here uses DEFINE_STATIC_CALL_NULL() to get a static_call defined + * from just a typename, as opposed to an actual function. + */ +DEFINE_STATIC_CALL_NULL(x86_pmu_handle_irq, *x86_pmu.handle_irq); +DEFINE_STATIC_CALL_NULL(x86_pmu_disable_all, *x86_pmu.disable_all); +DEFINE_STATIC_CALL_NULL(x86_pmu_enable_all, *x86_pmu.enable_all); +DEFINE_STATIC_CALL_NULL(x86_pmu_enable, *x86_pmu.enable); +DEFINE_STATIC_CALL_NULL(x86_pmu_disable, *x86_pmu.disable); + +DEFINE_STATIC_CALL_NULL(x86_pmu_add, *x86_pmu.add); +DEFINE_STATIC_CALL_NULL(x86_pmu_del, *x86_pmu.del); +DEFINE_STATIC_CALL_NULL(x86_pmu_read, *x86_pmu.read); + +DEFINE_STATIC_CALL_NULL(x86_pmu_schedule_events, *x86_pmu.schedule_events); +DEFINE_STATIC_CALL_NULL(x86_pmu_get_event_constraints, *x86_pmu.get_event_constraints); +DEFINE_STATIC_CALL_NULL(x86_pmu_put_event_constraints, *x86_pmu.put_event_constraints); + +DEFINE_STATIC_CALL_NULL(x86_pmu_start_scheduling, *x86_pmu.start_scheduling); +DEFINE_STATIC_CALL_NULL(x86_pmu_commit_scheduling, *x86_pmu.commit_scheduling); +DEFINE_STATIC_CALL_NULL(x86_pmu_stop_scheduling, *x86_pmu.stop_scheduling); + +DEFINE_STATIC_CALL_NULL(x86_pmu_sched_task, *x86_pmu.sched_task); +DEFINE_STATIC_CALL_NULL(x86_pmu_swap_task_ctx, *x86_pmu.swap_task_ctx); + +DEFINE_STATIC_CALL_NULL(x86_pmu_drain_pebs, *x86_pmu.drain_pebs); +DEFINE_STATIC_CALL_NULL(x86_pmu_pebs_aliases, *x86_pmu.pebs_aliases); + u64 __read_mostly hw_cache_event_ids [PERF_COUNT_HW_CACHE_MAX] [PERF_COUNT_HW_CACHE_OP_MAX] @@ -660,7 +689,7 @@ static void x86_pmu_disable(struct pmu *pmu) cpuc->enabled = 0; barrier(); - x86_pmu.disable_all(); + static_call(x86_pmu_disable_all)(); } void x86_pmu_enable_all(int added) @@ -907,8 +936,7 @@ int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign) if (cpuc->txn_flags & PERF_PMU_TXN_ADD) n0 -= cpuc->n_txn; - if (x86_pmu.start_scheduling) - x86_pmu.start_scheduling(cpuc); + static_call_cond(x86_pmu_start_scheduling)(cpuc); for (i = 0, wmin = X86_PMC_IDX_MAX, wmax = 0; i < n; i++) { c = cpuc->event_constraint[i]; @@ -925,7 +953,7 @@ int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign) * change due to external factors (sibling state, allow_tfa). */ if (!c || (c->flags & PERF_X86_EVENT_DYNAMIC)) { - c = x86_pmu.get_event_constraints(cpuc, i, cpuc->event_list[i]); + c = static_call(x86_pmu_get_event_constraints)(cpuc, i, cpuc->event_list[i]); cpuc->event_constraint[i] = c; } @@ -1008,8 +1036,7 @@ int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign) if (!unsched && assign) { for (i = 0; i < n; i++) { e = cpuc->event_list[i]; - if (x86_pmu.commit_scheduling) - x86_pmu.commit_scheduling(cpuc, i, assign[i]); + static_call_cond(x86_pmu_commit_scheduling)(cpuc, i, assign[i]); } } else { for (i = n0; i < n; i++) { @@ -1018,15 +1045,13 @@ int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign) /* * release events that failed scheduling */ - if (x86_pmu.put_event_constraints) - x86_pmu.put_event_constraints(cpuc, e); + static_call_cond(x86_pmu_put_event_constraints)(cpuc, e); cpuc->event_constraint[i] = NULL; } } - if (x86_pmu.stop_scheduling) - x86_pmu.stop_scheduling(cpuc); + static_call_cond(x86_pmu_stop_scheduling)(cpuc); return unsched ? -EINVAL : 0; } @@ -1226,7 +1251,7 @@ static void x86_pmu_enable(struct pmu *pmu) cpuc->enabled = 1; barrier(); - x86_pmu.enable_all(added); + static_call(x86_pmu_enable_all)(added); } static DEFINE_PER_CPU(u64 [X86_PMC_IDX_MAX], pmc_prev_left); @@ -1347,7 +1372,7 @@ static int x86_pmu_add(struct perf_event *event, int flags) if (cpuc->txn_flags & PERF_PMU_TXN_ADD) goto done_collect; - ret = x86_pmu.schedule_events(cpuc, n, assign); + ret = static_call(x86_pmu_schedule_events)(cpuc, n, assign); if (ret) goto out; /* @@ -1365,13 +1390,11 @@ done_collect: cpuc->n_added += n - n0; cpuc->n_txn += n - n0; - if (x86_pmu.add) { - /* - * This is before x86_pmu_enable() will call x86_pmu_start(), - * so we enable LBRs before an event needs them etc.. - */ - x86_pmu.add(event); - } + /* + * This is before x86_pmu_enable() will call x86_pmu_start(), + * so we enable LBRs before an event needs them etc.. + */ + static_call_cond(x86_pmu_add)(event); ret = 0; out: @@ -1399,7 +1422,7 @@ static void x86_pmu_start(struct perf_event *event, int flags) cpuc->events[idx] = event; __set_bit(idx, cpuc->active_mask); __set_bit(idx, cpuc->running); - x86_pmu.enable(event); + static_call(x86_pmu_enable)(event); perf_event_update_userpage(event); } @@ -1469,7 +1492,7 @@ void x86_pmu_stop(struct perf_event *event, int flags) struct hw_perf_event *hwc = &event->hw; if (test_bit(hwc->idx, cpuc->active_mask)) { - x86_pmu.disable(event); + static_call(x86_pmu_disable)(event); __clear_bit(hwc->idx, cpuc->active_mask); cpuc->events[hwc->idx] = NULL; WARN_ON_ONCE(hwc->state & PERF_HES_STOPPED); @@ -1519,8 +1542,7 @@ static void x86_pmu_del(struct perf_event *event, int flags) if (i >= cpuc->n_events - cpuc->n_added) --cpuc->n_added; - if (x86_pmu.put_event_constraints) - x86_pmu.put_event_constraints(cpuc, event); + static_call_cond(x86_pmu_put_event_constraints)(cpuc, event); /* Delete the array entry. */ while (++i < cpuc->n_events) { @@ -1533,13 +1555,12 @@ static void x86_pmu_del(struct perf_event *event, int flags) perf_event_update_userpage(event); do_del: - if (x86_pmu.del) { - /* - * This is after x86_pmu_stop(); so we disable LBRs after any - * event can need them etc.. - */ - x86_pmu.del(event); - } + + /* + * This is after x86_pmu_stop(); so we disable LBRs after any + * event can need them etc.. + */ + static_call_cond(x86_pmu_del)(event); } int x86_pmu_handle_irq(struct pt_regs *regs) @@ -1617,7 +1638,7 @@ perf_event_nmi_handler(unsigned int cmd, struct pt_regs *regs) return NMI_DONE; start_clock = sched_clock(); - ret = x86_pmu.handle_irq(regs); + ret = static_call(x86_pmu_handle_irq)(regs); finish_clock = sched_clock(); perf_sample_event_took(finish_clock - start_clock); @@ -1830,6 +1851,38 @@ ssize_t x86_event_sysfs_show(char *page, u64 config, u64 event) static struct attribute_group x86_pmu_attr_group; static struct attribute_group x86_pmu_caps_group; +static void x86_pmu_static_call_update(void) +{ + static_call_update(x86_pmu_handle_irq, x86_pmu.handle_irq); + static_call_update(x86_pmu_disable_all, x86_pmu.disable_all); + static_call_update(x86_pmu_enable_all, x86_pmu.enable_all); + static_call_update(x86_pmu_enable, x86_pmu.enable); + static_call_update(x86_pmu_disable, x86_pmu.disable); + + static_call_update(x86_pmu_add, x86_pmu.add); + static_call_update(x86_pmu_del, x86_pmu.del); + static_call_update(x86_pmu_read, x86_pmu.read); + + static_call_update(x86_pmu_schedule_events, x86_pmu.schedule_events); + static_call_update(x86_pmu_get_event_constraints, x86_pmu.get_event_constraints); + static_call_update(x86_pmu_put_event_constraints, x86_pmu.put_event_constraints); + + static_call_update(x86_pmu_start_scheduling, x86_pmu.start_scheduling); + static_call_update(x86_pmu_commit_scheduling, x86_pmu.commit_scheduling); + static_call_update(x86_pmu_stop_scheduling, x86_pmu.stop_scheduling); + + static_call_update(x86_pmu_sched_task, x86_pmu.sched_task); + static_call_update(x86_pmu_swap_task_ctx, x86_pmu.swap_task_ctx); + + static_call_update(x86_pmu_drain_pebs, x86_pmu.drain_pebs); + static_call_update(x86_pmu_pebs_aliases, x86_pmu.pebs_aliases); +} + +static void _x86_pmu_read(struct perf_event *event) +{ + x86_perf_event_update(event); +} + static int __init init_hw_perf_events(void) { struct x86_pmu_quirk *quirk; @@ -1898,6 +1951,11 @@ static int __init init_hw_perf_events(void) pr_info("... fixed-purpose events: %d\n", x86_pmu.num_counters_fixed); pr_info("... event mask: %016Lx\n", x86_pmu.intel_ctrl); + if (!x86_pmu.read) + x86_pmu.read = _x86_pmu_read; + + x86_pmu_static_call_update(); + /* * Install callbacks. Core will call them for each online * cpu. @@ -1934,11 +1992,9 @@ out: } early_initcall(init_hw_perf_events); -static inline void x86_pmu_read(struct perf_event *event) +static void x86_pmu_read(struct perf_event *event) { - if (x86_pmu.read) - return x86_pmu.read(event); - x86_perf_event_update(event); + static_call(x86_pmu_read)(event); } /* @@ -2015,7 +2071,7 @@ static int x86_pmu_commit_txn(struct pmu *pmu) if (!x86_pmu_initialized()) return -EAGAIN; - ret = x86_pmu.schedule_events(cpuc, n, assign); + ret = static_call(x86_pmu_schedule_events)(cpuc, n, assign); if (ret) return ret; @@ -2308,15 +2364,13 @@ static const struct attribute_group *x86_pmu_attr_groups[] = { static void x86_pmu_sched_task(struct perf_event_context *ctx, bool sched_in) { - if (x86_pmu.sched_task) - x86_pmu.sched_task(ctx, sched_in); + static_call_cond(x86_pmu_sched_task)(ctx, sched_in); } static void x86_pmu_swap_task_ctx(struct perf_event_context *prev, struct perf_event_context *next) { - if (x86_pmu.swap_task_ctx) - x86_pmu.swap_task_ctx(prev, next); + static_call_cond(x86_pmu_swap_task_ctx)(prev, next); } void perf_check_microcode(void) -- cgit v1.2.3