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authorWilco Dijkstra <wdijkstr@arm.com>2017-06-20 16:26:26 +0100
committerWilco Dijkstra <wdijkstr@arm.com>2017-06-20 16:26:26 +0100
commitbeb52f502f0477465313675d2a0fbf3962e130b8 (patch)
tree6d8953c8fab0f45f01c04ab89171a2211b599686 /benchtests/bench-skeleton.c
parentc0b23001a89b79f8d0bebe41bfbe64d840b13191 (diff)
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Improve math benchmark infrastructure
Improve support for math function benchmarking.  This patch adds
a feature that allows accurate benchmarking of traces extracted
from real workloads.  This is done by iterating over all samples
rather than repeating each sample many times (which completely
ignores branch prediction and cache effects).  A trace can be
added to existing math function inputs via
"## name: workload-<name>", followed by the trace.

        * benchtests/README: Describe workload feature.
        * benchtests/bench-skeleton.c (main): Add support for
        benchmarking traces from workloads.
Diffstat (limited to 'benchtests/bench-skeleton.c')
-rw-r--r--benchtests/bench-skeleton.c57
1 files changed, 39 insertions, 18 deletions
diff --git a/benchtests/bench-skeleton.c b/benchtests/bench-skeleton.c
index 09eb78df1b..3c6dad7055 100644
--- a/benchtests/bench-skeleton.c
+++ b/benchtests/bench-skeleton.c
@@ -68,34 +68,50 @@ main (int argc, char **argv)
       clock_gettime (CLOCK_MONOTONIC_RAW, &runtime);
       runtime.tv_sec += DURATION;
 
+      bool is_bench = strncmp (VARIANT (v), "workload-", 9) == 0;
       double d_total_i = 0;
       timing_t total = 0, max = 0, min = 0x7fffffffffffffff;
       int64_t c = 0;
+      uint64_t cur;
       while (1)
 	{
-	  for (i = 0; i < NUM_SAMPLES (v); i++)
+	  if (is_bench)
 	    {
-	      uint64_t cur;
+	      /* Benchmark a real trace of calls - all samples are iterated
+		 over once before repeating.  This models actual use more
+		 accurately than repeating the same sample many times.  */
 	      TIMING_NOW (start);
 	      for (k = 0; k < iters; k++)
-		BENCH_FUNC (v, i);
+		for (i = 0; i < NUM_SAMPLES (v); i++)
+		  BENCH_FUNC (v, i);
 	      TIMING_NOW (end);
-
 	      TIMING_DIFF (cur, start, end);
+	      TIMING_ACCUM (total, cur);
+	      d_total_i += iters * NUM_SAMPLES (v);
+	    }
+	  else
+	    for (i = 0; i < NUM_SAMPLES (v); i++)
+	      {
+		TIMING_NOW (start);
+		for (k = 0; k < iters; k++)
+		  BENCH_FUNC (v, i);
+		TIMING_NOW (end);
 
-	      if (cur > max)
-		max = cur;
+		TIMING_DIFF (cur, start, end);
 
-	      if (cur < min)
-		min = cur;
+		if (cur > max)
+		  max = cur;
 
-	      TIMING_ACCUM (total, cur);
-	      /* Accumulate timings for the value.  In the end we will divide
-	         by the total iterations.  */
-	      RESULT_ACCUM (cur, v, i, c * iters, (c + 1) * iters);
+		if (cur < min)
+		  min = cur;
 
-	      d_total_i += iters;
-	    }
+		TIMING_ACCUM (total, cur);
+		/* Accumulate timings for the value.  In the end we will divide
+		   by the total iterations.  */
+		RESULT_ACCUM (cur, v, i, c * iters, (c + 1) * iters);
+
+		d_total_i += iters;
+	      }
 	  c++;
 	  struct timespec curtime;
 
@@ -117,11 +133,16 @@ main (int argc, char **argv)
 
       json_attr_double (&json_ctx, "duration", d_total_s);
       json_attr_double (&json_ctx, "iterations", d_total_i);
-      json_attr_double (&json_ctx, "max", max / d_iters);
-      json_attr_double (&json_ctx, "min", min / d_iters);
-      json_attr_double (&json_ctx, "mean", d_total_s / d_total_i);
+      if (is_bench)
+	json_attr_double (&json_ctx, "throughput", d_total_s / d_total_i);
+      else
+	{
+	  json_attr_double (&json_ctx, "max", max / d_iters);
+	  json_attr_double (&json_ctx, "min", min / d_iters);
+	  json_attr_double (&json_ctx, "mean", d_total_s / d_total_i);
+	}
 
-      if (detailed)
+      if (detailed && !is_bench)
 	{
 	  json_array_begin (&json_ctx, "timings");