diff options
| -rw-r--r-- | include/linux/perf_counter.h | 4 | ||||
| -rw-r--r-- | kernel/perf_counter.c | 83 |
2 files changed, 83 insertions, 4 deletions
diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h index 6a384f04755a..de70a10b5ec8 100644 --- a/include/linux/perf_counter.h +++ b/include/linux/perf_counter.h @@ -178,8 +178,9 @@ struct perf_counter_attr { mmap : 1, /* include mmap data */ comm : 1, /* include comm data */ freq : 1, /* use freq, not period */ + inherit_stat : 1, /* per task counts */ - __reserved_1 : 53; + __reserved_1 : 52; __u32 wakeup_events; /* wakeup every n events */ __u32 __reserved_2; @@ -602,6 +603,7 @@ struct perf_counter_context { int nr_counters; int nr_active; int is_active; + int nr_stat; atomic_t refcount; struct task_struct *task; diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index a72c20e91953..385ca51c6e60 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -236,6 +236,8 @@ list_add_counter(struct perf_counter *counter, struct perf_counter_context *ctx) list_add_rcu(&counter->event_entry, &ctx->event_list); ctx->nr_counters++; + if (counter->attr.inherit_stat) + ctx->nr_stat++; } /* @@ -250,6 +252,8 @@ list_del_counter(struct perf_counter *counter, struct perf_counter_context *ctx) if (list_empty(&counter->list_entry)) return; ctx->nr_counters--; + if (counter->attr.inherit_stat) + ctx->nr_stat--; list_del_init(&counter->list_entry); list_del_rcu(&counter->event_entry); @@ -1006,6 +1010,76 @@ static int context_equiv(struct perf_counter_context *ctx1, && !ctx1->pin_count && !ctx2->pin_count; } +static void __perf_counter_read(void *counter); + +static void __perf_counter_sync_stat(struct perf_counter *counter, + struct perf_counter *next_counter) +{ + u64 value; + + if (!counter->attr.inherit_stat) + return; + + /* + * Update the counter value, we cannot use perf_counter_read() + * because we're in the middle of a context switch and have IRQs + * disabled, which upsets smp_call_function_single(), however + * we know the counter must be on the current CPU, therefore we + * don't need to use it. + */ + switch (counter->state) { + case PERF_COUNTER_STATE_ACTIVE: + __perf_counter_read(counter); + break; + + case PERF_COUNTER_STATE_INACTIVE: + update_counter_times(counter); + break; + + default: + break; + } + + /* + * In order to keep per-task stats reliable we need to flip the counter + * values when we flip the contexts. + */ + value = atomic64_read(&next_counter->count); + value = atomic64_xchg(&counter->count, value); + atomic64_set(&next_counter->count, value); + + /* + * XXX also sync time_enabled and time_running ? + */ +} + +#define list_next_entry(pos, member) \ + list_entry(pos->member.next, typeof(*pos), member) + +static void perf_counter_sync_stat(struct perf_counter_context *ctx, + struct perf_counter_context *next_ctx) +{ + struct perf_counter *counter, *next_counter; + + if (!ctx->nr_stat) + return; + + counter = list_first_entry(&ctx->event_list, + struct perf_counter, event_entry); + + next_counter = list_first_entry(&next_ctx->event_list, + struct perf_counter, event_entry); + + while (&counter->event_entry != &ctx->event_list && + &next_counter->event_entry != &next_ctx->event_list) { + + __perf_counter_sync_stat(counter, next_counter); + + counter = list_next_entry(counter, event_entry); + next_counter = list_next_entry(counter, event_entry); + } +} + /* * Called from scheduler to remove the counters of the current task, * with interrupts disabled. @@ -1061,6 +1135,8 @@ void perf_counter_task_sched_out(struct task_struct *task, ctx->task = next; next_ctx->task = task; do_switch = 0; + + perf_counter_sync_stat(ctx, next_ctx); } spin_unlock(&next_ctx->lock); spin_unlock(&ctx->lock); @@ -1350,7 +1426,7 @@ void perf_counter_task_tick(struct task_struct *curr, int cpu) /* * Cross CPU call to read the hardware counter */ -static void __read(void *info) +static void __perf_counter_read(void *info) { struct perf_counter *counter = info; struct perf_counter_context *ctx = counter->ctx; @@ -1372,7 +1448,7 @@ static u64 perf_counter_read(struct perf_counter *counter) */ if (counter->state == PERF_COUNTER_STATE_ACTIVE) { smp_call_function_single(counter->oncpu, - __read, counter, 1); + __perf_counter_read, counter, 1); } else if (counter->state == PERF_COUNTER_STATE_INACTIVE) { update_counter_times(counter); } @@ -4050,7 +4126,8 @@ static void sync_child_counter(struct perf_counter *child_counter, struct perf_counter *parent_counter = child_counter->parent; u64 child_val; - perf_counter_read_event(child_counter, child); + if (child_counter->attr.inherit_stat) + perf_counter_read_event(child_counter, child); child_val = atomic64_read(&child_counter->count); |
