Fix critical bug in GPU tracker.wip-2012.3-gpu-rtss13

1 files changed, 16 insertions, 5 deletions

diff --git a/include/litmus/gpu_affinity.h b/include/litmus/gpu_affinity.h
index f610f58b1f3b..197d4438d4f9 100644
--- a/include/litmus/gpu_affinity.h
+++ b/include/litmus/gpu_affinity.h
@@ -16,22 +16,33 @@ static inline void reset_gpu_tracker(struct task_struct* t)
 
 static inline void start_gpu_tracker(struct task_struct* t)
 {
-        t->rt_param.gpu_time_stamp = litmus_clock();
+        lt_t now = litmus_clock();
+
+        TRACE_TASK(t, "+++ starting gpu tracker @ %llu\n", now);
+//      WARN_ON(t->rt_param.gpu_time_stamp != 0); // already running!
+
+        if (likely(!t->rt_param.gpu_time_stamp))
+                t->rt_param.gpu_time_stamp = now;
 }
 
 static inline void stop_gpu_tracker(struct task_struct* t)
 {
         lt_t now = litmus_clock();
-        t->rt_param.accum_gpu_time += (now - t->rt_param.gpu_time_stamp);
-        t->rt_param.gpu_time_stamp = 0;
+
+        TRACE_TASK(t, "--- stopping gpu tracker @ %llu\n", now);
+//      WARN_ON(t->rt_param.gpu_time_stamp == 0); // already stopped!
+
+        if (likely(t->rt_param.gpu_time_stamp)) {
+                t->rt_param.accum_gpu_time += (now - t->rt_param.gpu_time_stamp);
+                t->rt_param.gpu_time_stamp = 0;
+        }
 }
 
 static inline lt_t get_gpu_time(struct task_struct* t)
 {
         lt_t accum = t->rt_param.accum_gpu_time;
-        if (t->rt_param.gpu_time_stamp != 0) {
+        if (t->rt_param.gpu_time_stamp != 0)
                 accum += (litmus_clock() - t->rt_param.gpu_time_stamp);
-        }
         return accum;
 }