Tweak gpu heuristics

2 files changed, 10 insertions, 12 deletions

diff --git a/include/litmus/trace.h b/include/litmus/trace.h
index 15bd645d2466..f10d8a0311cc 100644
--- a/include/litmus/trace.h
+++ b/include/litmus/trace.h
@@ -167,4 +167,7 @@ feather_callback void save_timestamp_hide_irq(unsigned long event);
 
 #define TS_RELEASE_LATENCY(when)        LTIMESTAMP(208, &(when))
 
+#define TS_UPDATE_GPU_EST_START         TIMESTAMP(210)
+#define TS_UPDATE_GPU_EST_END           TIMESTAMP(211)
+
 #endif /* !_SYS_TRACE_H_ */
diff --git a/litmus/gpu_affinity.c b/litmus/gpu_affinity.c
index e051fb7909a0..5c5d669421b3 100644
--- a/litmus/gpu_affinity.c
+++ b/litmus/gpu_affinity.c
@@ -7,6 +7,7 @@
 
 #include <litmus/sched_trace.h>
 
+/* two second cap on crazy observations */
 #define OBSERVATION_CAP ((lt_t)(2e9))
 
 // reason for skew: high outliers are less
@@ -14,7 +15,7 @@
 //#define HI_THRESHOLD 2
 //#define LO_THRESHOLD 4
 
-#define NUM_STDEV_NUM   1
+#define NUM_STDEV_NUM   3
 #define NUM_STDEV_DENOM 2
 
 #define MIN(a, b) ((a < b) ? a : b)
@@ -60,9 +61,8 @@ static lt_t isqrt(lt_t n)
          * (algo taken from wikipedia */
         lt_t res = 0;
         lt_t bit = ((lt_t)1) << (sizeof(n)*8-2);
-        while (bit > n) {
+        while (bit > n)
                 bit >>= 2;
-        }
 
         while (bit != 0) {
                 if (n >= res + bit) {
@@ -81,7 +81,6 @@ void update_gpu_estimate(struct task_struct *t, lt_t observed)
 {
         avg_est_t *est;
 
-
         BUG_ON(tsk_rt(t)->gpu_migration > MIG_LAST);
 
         est = &(tsk_rt(t)->gpu_migration_est[tsk_rt(t)->gpu_migration]);
@@ -122,18 +121,18 @@ void update_gpu_estimate(struct task_struct *t, lt_t observed)
                 }
         }
 
-        if (unlikely(est->count < AVG_EST_WINDOW_SIZE)) {
+        if (unlikely(est->count < AVG_EST_WINDOW_SIZE))
                 ++est->count;
-        }
-        else {
+        else
                 est->sum -= est->history[est->idx];
-        }
 
+        TS_UPDATE_GPU_EST_START;
         est->history[est->idx] = observed;
         est->sum += observed;
         est->avg = est->sum/est->count;
         est->std = isqrt(varience(est->history, est->avg, est->count));
         est->idx = (est->idx + 1) % AVG_EST_WINDOW_SIZE;
+        TS_UPDATE_GPU_EST_END;
 
         TRACE_TASK(t, "GPU est update after (dist = %d, obs = %llu): %llu\n",
                            tsk_rt(t)->gpu_migration,
@@ -168,8 +167,4 @@ out:
         return dist;
 }
 
-
-
-
 #endif
-