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 <eranian@googlemail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Kacur <jkacur@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 5 insertions, 3 deletions

diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index 9ec20fc6bd36..4845a214b9e7 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
 };