From: Ingo Molnar Date: Thu, 18 Aug 2016 08:03:35 +0000 (+0200) Subject: Merge branch 'perf/urgent' into perf/core, to pick up dependency X-Git-Tag: v4.9-rc1~164^2~22 X-Git-Url: http://git.cascardo.info/?p=cascardo%2Flinux.git;a=commitdiff_plain;h=bc06f00dbd71a839228f382540a834c3963b9312;hp=6c4687cc17a788a6dd8de3e27dbeabb7cbd3e066 Merge branch 'perf/urgent' into perf/core, to pick up dependency Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index d0efb5cb1b00..18a1acf86c90 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -1201,6 +1201,9 @@ static int x86_pmu_add(struct perf_event *event, int flags) * If group events scheduling transaction was started, * skip the schedulability test here, it will be performed * at commit time (->commit_txn) as a whole. + * + * If commit fails, we'll call ->del() on all events + * for which ->add() was called. */ if (cpuc->txn_flags & PERF_PMU_TXN_ADD) goto done_collect; @@ -1223,6 +1226,14 @@ 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); + } + ret = 0; out: return ret; @@ -1346,7 +1357,7 @@ static void x86_pmu_del(struct perf_event *event, int flags) event->hw.flags &= ~PERF_X86_EVENT_COMMITTED; /* - * If we're called during a txn, we don't need to do anything. + * If we're called during a txn, we only need to undo x86_pmu.add. * The events never got scheduled and ->cancel_txn will truncate * the event_list. * @@ -1354,7 +1365,7 @@ static void x86_pmu_del(struct perf_event *event, int flags) * an event added during that same TXN. */ if (cpuc->txn_flags & PERF_PMU_TXN_ADD) - return; + goto do_del; /* * Not a TXN, therefore cleanup properly. @@ -1384,6 +1395,15 @@ static void x86_pmu_del(struct perf_event *event, int flags) --cpuc->n_events; 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); + } } int x86_pmu_handle_irq(struct pt_regs *regs) diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index 2cbde2f449aa..88792f846d12 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -1907,13 +1907,6 @@ static void intel_pmu_disable_event(struct perf_event *event) cpuc->intel_ctrl_host_mask &= ~(1ull << hwc->idx); cpuc->intel_cp_status &= ~(1ull << hwc->idx); - /* - * must disable before any actual event - * because any event may be combined with LBR - */ - if (needs_branch_stack(event)) - intel_pmu_lbr_disable(event); - if (unlikely(hwc->config_base == MSR_ARCH_PERFMON_FIXED_CTR_CTRL)) { intel_pmu_disable_fixed(hwc); return; @@ -1925,6 +1918,14 @@ static void intel_pmu_disable_event(struct perf_event *event) intel_pmu_pebs_disable(event); } +static void intel_pmu_del_event(struct perf_event *event) +{ + if (needs_branch_stack(event)) + intel_pmu_lbr_del(event); + if (event->attr.precise_ip) + intel_pmu_pebs_del(event); +} + static void intel_pmu_enable_fixed(struct hw_perf_event *hwc) { int idx = hwc->idx - INTEL_PMC_IDX_FIXED; @@ -1968,12 +1969,6 @@ static void intel_pmu_enable_event(struct perf_event *event) intel_pmu_enable_bts(hwc->config); return; } - /* - * must enabled before any actual event - * because any event may be combined with LBR - */ - if (needs_branch_stack(event)) - intel_pmu_lbr_enable(event); if (event->attr.exclude_host) cpuc->intel_ctrl_guest_mask |= (1ull << hwc->idx); @@ -1994,6 +1989,14 @@ static void intel_pmu_enable_event(struct perf_event *event) __x86_pmu_enable_event(hwc, ARCH_PERFMON_EVENTSEL_ENABLE); } +static void intel_pmu_add_event(struct perf_event *event) +{ + if (event->attr.precise_ip) + intel_pmu_pebs_add(event); + if (needs_branch_stack(event)) + intel_pmu_lbr_add(event); +} + /* * Save and restart an expired event. Called by NMI contexts, * so it has to be careful about preempting normal event ops: @@ -3290,6 +3293,8 @@ static __initconst const struct x86_pmu intel_pmu = { .enable_all = intel_pmu_enable_all, .enable = intel_pmu_enable_event, .disable = intel_pmu_disable_event, + .add = intel_pmu_add_event, + .del = intel_pmu_del_event, .hw_config = intel_pmu_hw_config, .schedule_events = x86_schedule_events, .eventsel = MSR_ARCH_PERFMON_EVENTSEL0, diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c index 7ce9f3f669e6..248023f54c87 100644 --- a/arch/x86/events/intel/ds.c +++ b/arch/x86/events/intel/ds.c @@ -806,9 +806,55 @@ struct event_constraint *intel_pebs_constraints(struct perf_event *event) return &emptyconstraint; } -static inline bool pebs_is_enabled(struct cpu_hw_events *cpuc) +/* + * We need the sched_task callback even for per-cpu events when we use + * the large interrupt threshold, such that we can provide PID and TID + * to PEBS samples. + */ +static inline bool pebs_needs_sched_cb(struct cpu_hw_events *cpuc) +{ + return cpuc->n_pebs && (cpuc->n_pebs == cpuc->n_large_pebs); +} + +static inline void pebs_update_threshold(struct cpu_hw_events *cpuc) +{ + struct debug_store *ds = cpuc->ds; + u64 threshold; + + if (cpuc->n_pebs == cpuc->n_large_pebs) { + threshold = ds->pebs_absolute_maximum - + x86_pmu.max_pebs_events * x86_pmu.pebs_record_size; + } else { + threshold = ds->pebs_buffer_base + x86_pmu.pebs_record_size; + } + + ds->pebs_interrupt_threshold = threshold; +} + +static void +pebs_update_state(bool needed_cb, struct cpu_hw_events *cpuc, struct pmu *pmu) +{ + if (needed_cb != pebs_needs_sched_cb(cpuc)) { + if (!needed_cb) + perf_sched_cb_inc(pmu); + else + perf_sched_cb_dec(pmu); + + pebs_update_threshold(cpuc); + } +} + +void intel_pmu_pebs_add(struct perf_event *event) { - return (cpuc->pebs_enabled & ((1ULL << MAX_PEBS_EVENTS) - 1)); + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); + struct hw_perf_event *hwc = &event->hw; + bool needed_cb = pebs_needs_sched_cb(cpuc); + + cpuc->n_pebs++; + if (hwc->flags & PERF_X86_EVENT_FREERUNNING) + cpuc->n_large_pebs++; + + pebs_update_state(needed_cb, cpuc, event->ctx->pmu); } void intel_pmu_pebs_enable(struct perf_event *event) @@ -816,12 +862,9 @@ void intel_pmu_pebs_enable(struct perf_event *event) struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); struct hw_perf_event *hwc = &event->hw; struct debug_store *ds = cpuc->ds; - bool first_pebs; - u64 threshold; hwc->config &= ~ARCH_PERFMON_EVENTSEL_INT; - first_pebs = !pebs_is_enabled(cpuc); cpuc->pebs_enabled |= 1ULL << hwc->idx; if (event->hw.flags & PERF_X86_EVENT_PEBS_LDLAT) @@ -830,46 +873,34 @@ void intel_pmu_pebs_enable(struct perf_event *event) cpuc->pebs_enabled |= 1ULL << 63; /* - * When the event is constrained enough we can use a larger - * threshold and run the event with less frequent PMI. + * Use auto-reload if possible to save a MSR write in the PMI. + * This must be done in pmu::start(), because PERF_EVENT_IOC_PERIOD. */ - if (hwc->flags & PERF_X86_EVENT_FREERUNNING) { - threshold = ds->pebs_absolute_maximum - - x86_pmu.max_pebs_events * x86_pmu.pebs_record_size; - - if (first_pebs) - perf_sched_cb_inc(event->ctx->pmu); - } else { - threshold = ds->pebs_buffer_base + x86_pmu.pebs_record_size; - - /* - * If not all events can use larger buffer, - * roll back to threshold = 1 - */ - if (!first_pebs && - (ds->pebs_interrupt_threshold > threshold)) - perf_sched_cb_dec(event->ctx->pmu); - } - - /* Use auto-reload if possible to save a MSR write in the PMI */ if (hwc->flags & PERF_X86_EVENT_AUTO_RELOAD) { ds->pebs_event_reset[hwc->idx] = (u64)(-hwc->sample_period) & x86_pmu.cntval_mask; } +} - if (first_pebs || ds->pebs_interrupt_threshold > threshold) - ds->pebs_interrupt_threshold = threshold; +void intel_pmu_pebs_del(struct perf_event *event) +{ + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); + struct hw_perf_event *hwc = &event->hw; + bool needed_cb = pebs_needs_sched_cb(cpuc); + + cpuc->n_pebs--; + if (hwc->flags & PERF_X86_EVENT_FREERUNNING) + cpuc->n_large_pebs--; + + pebs_update_state(needed_cb, cpuc, event->ctx->pmu); } void intel_pmu_pebs_disable(struct perf_event *event) { struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); struct hw_perf_event *hwc = &event->hw; - struct debug_store *ds = cpuc->ds; - bool large_pebs = ds->pebs_interrupt_threshold > - ds->pebs_buffer_base + x86_pmu.pebs_record_size; - if (large_pebs) + if (cpuc->n_pebs == cpuc->n_large_pebs) intel_pmu_drain_pebs_buffer(); cpuc->pebs_enabled &= ~(1ULL << hwc->idx); @@ -879,9 +910,6 @@ void intel_pmu_pebs_disable(struct perf_event *event) else if (event->hw.flags & PERF_X86_EVENT_PEBS_ST) cpuc->pebs_enabled &= ~(1ULL << 63); - if (large_pebs && !pebs_is_enabled(cpuc)) - perf_sched_cb_dec(event->ctx->pmu); - if (cpuc->enabled) wrmsrl(MSR_IA32_PEBS_ENABLE, cpuc->pebs_enabled); diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c index 707d358e0dff..fc6cf21c535e 100644 --- a/arch/x86/events/intel/lbr.c +++ b/arch/x86/events/intel/lbr.c @@ -380,7 +380,6 @@ static void __intel_pmu_lbr_save(struct x86_perf_task_context *task_ctx) void intel_pmu_lbr_sched_task(struct perf_event_context *ctx, bool sched_in) { - struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); struct x86_perf_task_context *task_ctx; /* @@ -390,31 +389,21 @@ void intel_pmu_lbr_sched_task(struct perf_event_context *ctx, bool sched_in) */ task_ctx = ctx ? ctx->task_ctx_data : NULL; if (task_ctx) { - if (sched_in) { + if (sched_in) __intel_pmu_lbr_restore(task_ctx); - cpuc->lbr_context = ctx; - } else { + else __intel_pmu_lbr_save(task_ctx); - } return; } /* - * When sampling the branck stack in system-wide, it may be - * necessary to flush the stack on context switch. This happens - * when the branch stack does not tag its entries with the pid - * of the current task. Otherwise it becomes impossible to - * associate a branch entry with a task. This ambiguity is more - * likely to appear when the branch stack supports priv level - * filtering and the user sets it to monitor only at the user - * level (which could be a useful measurement in system-wide - * mode). In that case, the risk is high of having a branch - * stack with branch from multiple tasks. - */ - if (sched_in) { + * Since a context switch can flip the address space and LBR entries + * are not tagged with an identifier, we need to wipe the LBR, even for + * per-cpu events. You simply cannot resolve the branches from the old + * address space. + */ + if (sched_in) intel_pmu_lbr_reset(); - cpuc->lbr_context = ctx; - } } static inline bool branch_user_callstack(unsigned br_sel) @@ -422,7 +411,7 @@ static inline bool branch_user_callstack(unsigned br_sel) return (br_sel & X86_BR_USER) && (br_sel & X86_BR_CALL_STACK); } -void intel_pmu_lbr_enable(struct perf_event *event) +void intel_pmu_lbr_add(struct perf_event *event) { struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); struct x86_perf_task_context *task_ctx; @@ -430,27 +419,38 @@ void intel_pmu_lbr_enable(struct perf_event *event) if (!x86_pmu.lbr_nr) return; - /* - * Reset the LBR stack if we changed task context to - * avoid data leaks. - */ - if (event->ctx->task && cpuc->lbr_context != event->ctx) { - intel_pmu_lbr_reset(); - cpuc->lbr_context = event->ctx; - } cpuc->br_sel = event->hw.branch_reg.reg; - if (branch_user_callstack(cpuc->br_sel) && event->ctx && - event->ctx->task_ctx_data) { + if (branch_user_callstack(cpuc->br_sel) && event->ctx->task_ctx_data) { task_ctx = event->ctx->task_ctx_data; task_ctx->lbr_callstack_users++; } - cpuc->lbr_users++; + /* + * Request pmu::sched_task() callback, which will fire inside the + * regular perf event scheduling, so that call will: + * + * - restore or wipe; when LBR-callstack, + * - wipe; otherwise, + * + * when this is from __perf_event_task_sched_in(). + * + * However, if this is from perf_install_in_context(), no such callback + * will follow and we'll need to reset the LBR here if this is the + * first LBR event. + * + * The problem is, we cannot tell these cases apart... but we can + * exclude the biggest chunk of cases by looking at + * event->total_time_running. An event that has accrued runtime cannot + * be 'new'. Conversely, a new event can get installed through the + * context switch path for the first time. + */ perf_sched_cb_inc(event->ctx->pmu); + if (!cpuc->lbr_users++ && !event->total_time_running) + intel_pmu_lbr_reset(); } -void intel_pmu_lbr_disable(struct perf_event *event) +void intel_pmu_lbr_del(struct perf_event *event) { struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); struct x86_perf_task_context *task_ctx; @@ -467,12 +467,6 @@ void intel_pmu_lbr_disable(struct perf_event *event) cpuc->lbr_users--; WARN_ON_ONCE(cpuc->lbr_users < 0); perf_sched_cb_dec(event->ctx->pmu); - - if (cpuc->enabled && !cpuc->lbr_users) { - __intel_pmu_lbr_disable(); - /* avoid stale pointer */ - cpuc->lbr_context = NULL; - } } void intel_pmu_lbr_enable_all(bool pmi) diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h index 8c4a47706296..5874d8de1f8d 100644 --- a/arch/x86/events/perf_event.h +++ b/arch/x86/events/perf_event.h @@ -194,12 +194,13 @@ struct cpu_hw_events { */ struct debug_store *ds; u64 pebs_enabled; + int n_pebs; + int n_large_pebs; /* * Intel LBR bits */ int lbr_users; - void *lbr_context; struct perf_branch_stack lbr_stack; struct perf_branch_entry lbr_entries[MAX_LBR_ENTRIES]; struct er_account *lbr_sel; @@ -508,6 +509,8 @@ struct x86_pmu { void (*enable_all)(int added); void (*enable)(struct perf_event *); void (*disable)(struct perf_event *); + void (*add)(struct perf_event *); + void (*del)(struct perf_event *); int (*hw_config)(struct perf_event *event); int (*schedule_events)(struct cpu_hw_events *cpuc, int n, int *assign); unsigned eventsel; @@ -888,6 +891,10 @@ extern struct event_constraint intel_skl_pebs_event_constraints[]; struct event_constraint *intel_pebs_constraints(struct perf_event *event); +void intel_pmu_pebs_add(struct perf_event *event); + +void intel_pmu_pebs_del(struct perf_event *event); + void intel_pmu_pebs_enable(struct perf_event *event); void intel_pmu_pebs_disable(struct perf_event *event); @@ -906,9 +913,9 @@ u64 lbr_from_signext_quirk_wr(u64 val); void intel_pmu_lbr_reset(void); -void intel_pmu_lbr_enable(struct perf_event *event); +void intel_pmu_lbr_add(struct perf_event *event); -void intel_pmu_lbr_disable(struct perf_event *event); +void intel_pmu_lbr_del(struct perf_event *event); void intel_pmu_lbr_enable_all(bool pmi); diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 2b6b43cc0dd5..529c41fa73c8 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -774,6 +774,9 @@ struct perf_cpu_context { #ifdef CONFIG_CGROUP_PERF struct perf_cgroup *cgrp; #endif + + struct list_head sched_cb_entry; + int sched_cb_usage; }; struct perf_output_handle { diff --git a/kernel/events/core.c b/kernel/events/core.c index 1903b8f3a705..803481cb6cbd 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1796,6 +1796,8 @@ group_sched_out(struct perf_event *group_event, struct perf_event *event; int state = group_event->state; + perf_pmu_disable(ctx->pmu); + event_sched_out(group_event, cpuctx, ctx); /* @@ -1804,6 +1806,8 @@ group_sched_out(struct perf_event *group_event, list_for_each_entry(event, &group_event->sibling_list, group_entry) event_sched_out(event, cpuctx, ctx); + perf_pmu_enable(ctx->pmu); + if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive) cpuctx->exclusive = 0; } @@ -2801,19 +2805,36 @@ unlock: } } +static DEFINE_PER_CPU(struct list_head, sched_cb_list); + void perf_sched_cb_dec(struct pmu *pmu) { + struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); + this_cpu_dec(perf_sched_cb_usages); + + if (!--cpuctx->sched_cb_usage) + list_del(&cpuctx->sched_cb_entry); } + void perf_sched_cb_inc(struct pmu *pmu) { + struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); + + if (!cpuctx->sched_cb_usage++) + list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list)); + this_cpu_inc(perf_sched_cb_usages); } /* * This function provides the context switch callback to the lower code * layer. It is invoked ONLY when the context switch callback is enabled. + * + * This callback is relevant even to per-cpu events; for example multi event + * PEBS requires this to provide PID/TID information. This requires we flush + * all queued PEBS records before we context switch to a new task. */ static void perf_pmu_sched_task(struct task_struct *prev, struct task_struct *next, @@ -2821,34 +2842,24 @@ static void perf_pmu_sched_task(struct task_struct *prev, { struct perf_cpu_context *cpuctx; struct pmu *pmu; - unsigned long flags; if (prev == next) return; - local_irq_save(flags); + list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) { + pmu = cpuctx->unique_pmu; /* software PMUs will not have sched_task */ - rcu_read_lock(); - - list_for_each_entry_rcu(pmu, &pmus, entry) { - if (pmu->sched_task) { - cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); - - perf_ctx_lock(cpuctx, cpuctx->task_ctx); - - perf_pmu_disable(pmu); + if (WARN_ON_ONCE(!pmu->sched_task)) + continue; - pmu->sched_task(cpuctx->task_ctx, sched_in); + perf_ctx_lock(cpuctx, cpuctx->task_ctx); + perf_pmu_disable(pmu); - perf_pmu_enable(pmu); + pmu->sched_task(cpuctx->task_ctx, sched_in); - perf_ctx_unlock(cpuctx, cpuctx->task_ctx); - } + perf_pmu_enable(pmu); + perf_ctx_unlock(cpuctx, cpuctx->task_ctx); } - - rcu_read_unlock(); - - local_irq_restore(flags); } static void perf_event_switch(struct task_struct *task, @@ -10385,6 +10396,8 @@ static void __init perf_event_init_all_cpus(void) INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu)); raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu)); + + INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu)); } }