Framework for performance benchmarking of functions

See benchtests/Makefile to know how to use it.

1 files changed, 75 insertions, 0 deletions

diff --git a/benchtests/bench-skeleton.c b/benchtests/bench-skeleton.c
new file mode 100644
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+++ b/benchtests/bench-skeleton.c
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+/* Skeleton for benchmark programs.
+   Copyright (C) 2013 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <string.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <time.h>
+#include <inttypes.h>
+
+int
+main (int argc, char **argv)
+{
+  unsigned long i, j, k;
+  uint64_t total = 0, max = 0, min = 0x7fffffffffffffff;
+  struct timespec start, end;
+
+  memset (&start, 0, sizeof (start));
+  memset (&end, 0, sizeof (end));
+
+  clock_getres (CLOCK_PROCESS_CPUTIME_ID, &start);
+
+  /* Measure 1000 times the resolution of the clock.  So for a 1ns resolution
+     clock, we measure 1000 iterations of the function call at a time.
+     Measurements close to the minimum clock resolution won't make much sense,
+     but it's better than having nothing at all.  */
+  unsigned long iters = 1000 * start.tv_nsec;
+  unsigned long total_iters = ITER / iters;
+
+  for (i = 0; i < NUM_SAMPLES; i++)
+    {
+      for (j = 0; j < total_iters; j ++)
+	{
+	  clock_gettime (CLOCK_PROCESS_CPUTIME_ID, &start);
+	  for (k = 0; k < iters; k++)
+	    BENCH_FUNC(i);
+	  clock_gettime (CLOCK_PROCESS_CPUTIME_ID, &end);
+
+	  uint64_t cur = (end.tv_nsec - start.tv_nsec
+			 + ((end.tv_sec - start.tv_sec)
+			    * (uint64_t) 1000000000));
+
+	  if (cur > max)
+	    max = cur;
+
+	  if (cur < min)
+	    min = cur;
+
+	  total += cur;
+	}
+    }
+
+  double d_total_s = total * 1e-9;
+  double d_iters = iters;
+  double d_total_i = (double)ITER * NUM_SAMPLES;
+  printf (FUNCNAME ": ITERS:%g: TOTAL:%gs, MAX:%gns, MIN:%gns, %g iter/s\n",
+	  d_total_i, d_total_s, max / d_iters, min / d_iters,
+	  d_total_i / d_total_s);
+
+  return 0;
+}