diff options
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event_intel_cqm.c | 195 | ||||
| -rw-r--r-- | include/linux/perf_event.h | 1 | ||||
| -rw-r--r-- | include/uapi/linux/perf_event.h | 1 | ||||
| -rw-r--r-- | kernel/events/core.c | 2 |
4 files changed, 178 insertions, 21 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_intel_cqm.c b/arch/x86/kernel/cpu/perf_event_intel_cqm.c index b5d9d746dbc0..8003d87afd89 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_cqm.c +++ b/arch/x86/kernel/cpu/perf_event_intel_cqm.c @@ -182,23 +182,124 @@ fail: /* * Determine if @a and @b measure the same set of tasks. + * + * If @a and @b measure the same set of tasks then we want to share a + * single RMID. */ static bool __match_event(struct perf_event *a, struct perf_event *b) { + /* Per-cpu and task events don't mix */ if ((a->attach_state & PERF_ATTACH_TASK) != (b->attach_state & PERF_ATTACH_TASK)) return false; - /* not task */ +#ifdef CONFIG_CGROUP_PERF + if (a->cgrp != b->cgrp) + return false; +#endif + + /* If not task event, we're machine wide */ + if (!(b->attach_state & PERF_ATTACH_TASK)) + return true; + + /* + * Events that target same task are placed into the same cache group. + */ + if (a->hw.cqm_target == b->hw.cqm_target) + return true; + + /* + * Are we an inherited event? + */ + if (b->parent == a) + return true; + + return false; +} + +#ifdef CONFIG_CGROUP_PERF +static inline struct perf_cgroup *event_to_cgroup(struct perf_event *event) +{ + if (event->attach_state & PERF_ATTACH_TASK) + return perf_cgroup_from_task(event->hw.cqm_target); - return true; /* if not task, we're machine wide */ + return event->cgrp; } +#endif /* * Determine if @a's tasks intersect with @b's tasks + * + * There are combinations of events that we explicitly prohibit, + * + * PROHIBITS + * system-wide -> cgroup and task + * cgroup -> system-wide + * -> task in cgroup + * task -> system-wide + * -> task in cgroup + * + * Call this function before allocating an RMID. */ static bool __conflict_event(struct perf_event *a, struct perf_event *b) { +#ifdef CONFIG_CGROUP_PERF + /* + * We can have any number of cgroups but only one system-wide + * event at a time. + */ + if (a->cgrp && b->cgrp) { + struct perf_cgroup *ac = a->cgrp; + struct perf_cgroup *bc = b->cgrp; + + /* + * This condition should have been caught in + * __match_event() and we should be sharing an RMID. + */ + WARN_ON_ONCE(ac == bc); + + if (cgroup_is_descendant(ac->css.cgroup, bc->css.cgroup) || + cgroup_is_descendant(bc->css.cgroup, ac->css.cgroup)) + return true; + + return false; + } + + if (a->cgrp || b->cgrp) { + struct perf_cgroup *ac, *bc; + + /* + * cgroup and system-wide events are mutually exclusive + */ + if ((a->cgrp && !(b->attach_state & PERF_ATTACH_TASK)) || + (b->cgrp && !(a->attach_state & PERF_ATTACH_TASK))) + return true; + + /* + * Ensure neither event is part of the other's cgroup + */ + ac = event_to_cgroup(a); + bc = event_to_cgroup(b); + if (ac == bc) + return true; + + /* + * Must have cgroup and non-intersecting task events. + */ + if (!ac || !bc) + return false; + + /* + * We have cgroup and task events, and the task belongs + * to a cgroup. Check for for overlap. + */ + if (cgroup_is_descendant(ac->css.cgroup, bc->css.cgroup) || + cgroup_is_descendant(bc->css.cgroup, ac->css.cgroup)) + return true; + + return false; + } +#endif /* * If one of them is not a task, same story as above with cgroups. */ @@ -245,9 +346,16 @@ static int intel_cqm_setup_event(struct perf_event *event, static void intel_cqm_event_read(struct perf_event *event) { - unsigned long rmid = event->hw.cqm_rmid; + unsigned long rmid; u64 val; + /* + * Task events are handled by intel_cqm_event_count(). + */ + if (event->cpu == -1) + return; + + rmid = event->hw.cqm_rmid; val = __rmid_read(rmid); /* @@ -259,6 +367,63 @@ static void intel_cqm_event_read(struct perf_event *event) local64_set(&event->count, val); } +struct rmid_read { + unsigned int rmid; + atomic64_t value; +}; + +static void __intel_cqm_event_count(void *info) +{ + struct rmid_read *rr = info; + u64 val; + + val = __rmid_read(rr->rmid); + + if (val & (RMID_VAL_ERROR | RMID_VAL_UNAVAIL)) + return; + + atomic64_add(val, &rr->value); +} + +static inline bool cqm_group_leader(struct perf_event *event) +{ + return !list_empty(&event->hw.cqm_groups_entry); +} + +static u64 intel_cqm_event_count(struct perf_event *event) +{ + struct rmid_read rr = { + .rmid = event->hw.cqm_rmid, + .value = ATOMIC64_INIT(0), + }; + + /* + * We only need to worry about task events. System-wide events + * are handled like usual, i.e. entirely with + * intel_cqm_event_read(). + */ + if (event->cpu != -1) + return __perf_event_count(event); + + /* + * Only the group leader gets to report values. This stops us + * reporting duplicate values to userspace, and gives us a clear + * rule for which task gets to report the values. + * + * Note that it is impossible to attribute these values to + * specific packages - we forfeit that ability when we create + * task events. + */ + if (!cqm_group_leader(event)) + return 0; + + on_each_cpu_mask(&cqm_cpumask, __intel_cqm_event_count, &rr, 1); + + local64_set(&event->count, atomic64_read(&rr.value)); + + return __perf_event_count(event); +} + static void intel_cqm_event_start(struct perf_event *event, int mode) { struct intel_cqm_state *state = this_cpu_ptr(&cqm_state); @@ -344,7 +509,7 @@ static void intel_cqm_event_destroy(struct perf_event *event) /* * And we're the group leader.. */ - if (!list_empty(&event->hw.cqm_groups_entry)) { + if (cqm_group_leader(event)) { /* * If there was a group_other, make that leader, otherwise * destroy the group and return the RMID. @@ -365,17 +530,6 @@ static void intel_cqm_event_destroy(struct perf_event *event) static struct pmu intel_cqm_pmu; -/* - * XXX there's a bit of a problem in that we cannot simply do the one - * event per node as one would want, since that one event would one get - * scheduled on the one cpu. But we want to 'schedule' the RMID on all - * CPUs. - * - * This means we want events for each CPU, however, that generates a lot - * of duplicate values out to userspace -- this is not to be helped - * unless we want to change the core code in some way. Fore more info, - * see intel_cqm_event_read(). - */ static int intel_cqm_event_init(struct perf_event *event) { struct perf_event *group = NULL; @@ -387,9 +541,6 @@ static int intel_cqm_event_init(struct perf_event *event) if (event->attr.config & ~QOS_EVENT_MASK) return -EINVAL; - if (event->cpu == -1) - return -EINVAL; - /* unsupported modes and filters */ if (event->attr.exclude_user || event->attr.exclude_kernel || @@ -407,7 +558,8 @@ static int intel_cqm_event_init(struct perf_event *event) mutex_lock(&cache_mutex); - err = intel_cqm_setup_event(event, &group); /* will also set rmid */ + /* Will also set rmid */ + err = intel_cqm_setup_event(event, &group); if (err) goto out; @@ -470,6 +622,7 @@ static struct pmu intel_cqm_pmu = { .start = intel_cqm_event_start, .stop = intel_cqm_event_stop, .read = intel_cqm_event_read, + .count = intel_cqm_event_count, }; static inline void cqm_pick_event_reader(int cpu) @@ -599,8 +752,8 @@ static int __init intel_cqm_init(void) __perf_cpu_notifier(intel_cqm_cpu_notifier); - ret = perf_pmu_register(&intel_cqm_pmu, "intel_cqm", -1); - + ret = perf_pmu_register(&intel_cqm_pmu, "intel_cqm", + PERF_TYPE_INTEL_CQM); if (ret) pr_err("Intel CQM perf registration failed: %d\n", ret); else diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index ca5504c48f4f..dac4c2831d82 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -129,6 +129,7 @@ struct hw_perf_event { struct list_head cqm_events_entry; struct list_head cqm_groups_entry; struct list_head cqm_group_entry; + struct task_struct *cqm_target; }; #ifdef CONFIG_HAVE_HW_BREAKPOINT struct { /* breakpoint */ diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index 1e3cd07cf76e..3c8b45de57ec 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -32,6 +32,7 @@ enum perf_type_id { PERF_TYPE_HW_CACHE = 3, PERF_TYPE_RAW = 4, PERF_TYPE_BREAKPOINT = 5, + PERF_TYPE_INTEL_CQM = 6, PERF_TYPE_MAX, /* non-ABI */ }; diff --git a/kernel/events/core.c b/kernel/events/core.c index 1fc3bae5904a..71109a045450 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7181,6 +7181,8 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, else if (attr->type == PERF_TYPE_BREAKPOINT) event->hw.bp_target = task; #endif + else if (attr->type == PERF_TYPE_INTEL_CQM) + event->hw.cqm_target = task; } if (!overflow_handler && parent_event) { |