From 8e5799b1ad2a0567fdfaaf0e91b40efee010f2c1 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 2 Jun 2009 15:08:15 +0200 Subject: [PATCH] perf_counter: Add unique counter id Stephan raised the issue that we currently cannot distinguish between similar counters within a group (PERF_RECORD_GROUP uses the config value as identifier). Therefore, generate a new ID for each counter using a global u64 sequence counter. Reported-by: Stephane Eranian Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Paul Mackerras Cc: Corey Ashford Cc: Marcelo Tosatti Cc: Arnaldo Carvalho de Melo Cc: Thomas Gleixner Cc: John Kacur LKML-Reference: Signed-off-by: Ingo Molnar --- include/linux/perf_counter.h | 8 +++++--- kernel/perf_counter.c | 9 +++++++-- 2 files changed, 12 insertions(+), 5 deletions(-) diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h index 9ec20fc6..4845a21 100644 --- a/include/linux/perf_counter.h +++ b/include/linux/perf_counter.h @@ -114,8 +114,9 @@ enum perf_counter_record_format { * in increasing order of bit value, after the counter value. */ enum perf_counter_read_format { - PERF_FORMAT_TOTAL_TIME_ENABLED = 1, - PERF_FORMAT_TOTAL_TIME_RUNNING = 2, + PERF_FORMAT_TOTAL_TIME_ENABLED = 1U << 0, + PERF_FORMAT_TOTAL_TIME_RUNNING = 1U << 1, + PERF_FORMAT_ID = 1U << 2, }; /* @@ -290,7 +291,7 @@ enum perf_event_type { * { u32 cpu, res; } && PERF_RECORD_CPU * * { u64 nr; - * { u64 event, val; } cnt[nr]; } && PERF_RECORD_GROUP + * { u64 id, val; } cnt[nr]; } && PERF_RECORD_GROUP * * { u16 nr, * hv, @@ -503,6 +504,7 @@ struct perf_counter { struct rcu_head rcu_head; struct pid_namespace *ns; + u64 id; #endif }; diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index caa012c..978ecfc 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -1510,6 +1510,8 @@ perf_read_hw(struct perf_counter *counter, char __user *buf, size_t count) if (counter->hw_event.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) values[n++] = counter->total_time_running + atomic64_read(&counter->child_total_time_running); + if (counter->hw_event.read_format & PERF_FORMAT_ID) + values[n++] = counter->id; mutex_unlock(&counter->child_mutex); if (count < n * sizeof(u64)) @@ -2303,7 +2305,7 @@ static void perf_counter_output(struct perf_counter *counter, u32 pid, tid; } tid_entry; struct { - u64 event; + u64 id; u64 counter; } group_entry; struct perf_callchain_entry *callchain = NULL; @@ -2416,7 +2418,7 @@ static void perf_counter_output(struct perf_counter *counter, if (sub != counter) sub->pmu->read(sub); - group_entry.event = sub->hw_event.config; + group_entry.id = sub->id; group_entry.counter = atomic64_read(&sub->count); perf_output_put(&handle, group_entry); @@ -3375,6 +3377,8 @@ done: return counter; } +static atomic64_t perf_counter_id; + /** * sys_perf_counter_open - open a performance counter, associate it to a task/cpu * @@ -3470,6 +3474,7 @@ SYSCALL_DEFINE5(perf_counter_open, mutex_unlock(¤t->perf_counter_mutex); counter->ns = get_pid_ns(current->nsproxy->pid_ns); + counter->id = atomic64_inc_return(&perf_counter_id); fput_light(counter_file, fput_needed2); -- 2.7.4