1 files changed, 34 insertions, 8 deletions

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 517d827f4982..cb6c0d2af68f 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -674,6 +674,8 @@ event_sched_in(struct perf_event *event,
 
         event->tstamp_running += ctx->time - event->tstamp_stopped;
 
+        event->shadow_ctx_time = ctx->time - ctx->timestamp;
+
         if (!is_software_event(event))
                 cpuctx->active_oncpu++;
         ctx->nr_active++;
@@ -3396,7 +3398,8 @@ static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
 }
 
 static void perf_output_read_one(struct perf_output_handle *handle,
-                                 struct perf_event *event)
+                                 struct perf_event *event,
+                                 u64 enabled, u64 running)
 {
         u64 read_format = event->attr.read_format;
         u64 values[4];
@@ -3404,11 +3407,11 @@ static void perf_output_read_one(struct perf_output_handle *handle,
 
         values[n++] = perf_event_count(event);
         if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
-                values[n++] = event->total_time_enabled +
+                values[n++] = enabled +
                         atomic64_read(&event->child_total_time_enabled);
         }
         if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
-                values[n++] = event->total_time_running +
+                values[n++] = running +
                         atomic64_read(&event->child_total_time_running);
         }
         if (read_format & PERF_FORMAT_ID)
@@ -3421,7 +3424,8 @@ static void perf_output_read_one(struct perf_output_handle *handle,
  * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
  */
 static void perf_output_read_group(struct perf_output_handle *handle,
-                            struct perf_event *event)
+                            struct perf_event *event,
+                            u64 enabled, u64 running)
 {
         struct perf_event *leader = event->group_leader, *sub;
         u64 read_format = event->attr.read_format;
@@ -3431,10 +3435,10 @@ static void perf_output_read_group(struct perf_output_handle *handle,
         values[n++] = 1 + leader->nr_siblings;
 
         if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
-                values[n++] = leader->total_time_enabled;
+                values[n++] = enabled;
 
         if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
-                values[n++] = leader->total_time_running;
+                values[n++] = running;
 
         if (leader != event)
                 leader->pmu->read(leader);
@@ -3459,13 +3463,35 @@ static void perf_output_read_group(struct perf_output_handle *handle,
         }
 }
 
+#define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
+                                 PERF_FORMAT_TOTAL_TIME_RUNNING)
+
 static void perf_output_read(struct perf_output_handle *handle,
                              struct perf_event *event)
 {
+        u64 enabled = 0, running = 0, now, ctx_time;
+        u64 read_format = event->attr.read_format;
+
+        /*
+         * compute total_time_enabled, total_time_running
+         * based on snapshot values taken when the event
+         * was last scheduled in.
+         *
+         * we cannot simply called update_context_time()
+         * because of locking issue as we are called in
+         * NMI context
+         */
+        if (read_format & PERF_FORMAT_TOTAL_TIMES) {
+                now = perf_clock();
+                ctx_time = event->shadow_ctx_time + now;
+                enabled = ctx_time - event->tstamp_enabled;
+                running = ctx_time - event->tstamp_running;
+        }
+
         if (event->attr.read_format & PERF_FORMAT_GROUP)
-                perf_output_read_group(handle, event);
+                perf_output_read_group(handle, event, enabled, running);
         else
-                perf_output_read_one(handle, event);
+                perf_output_read_one(handle, event, enabled, running);
 }
 
 void perf_output_sample(struct perf_output_handle *handle,