Framework for performance benchmarking of functions

See benchtests/Makefile to know how to use it.

4 files changed, 136 insertions, 0 deletions

diff --git a/benchtests/Makefile b/benchtests/Makefile
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index 0000000000..74938b925c
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+++ b/benchtests/Makefile
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+# 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/>.
+
+
+# Makefile for benchmark tests.  The only useful target here is `bench`.
+
+# Adding a new function `foo`:
+# ---------------------------
+
+# - Append the function name to the bench variable
+
+# - Define foo-ITER with the number of iterations you want to run.  Keep it
+#   high enough that the overhead of clock_gettime is only a small fraction of
+#   the total run time of the test.
+
+# - Define foo-ARGLIST as a colon separated list of types of the input
+#   arguments.  Use `void` if function does not take any inputs.  Put in quotes
+#   if the input argument is a pointer, e.g.:
+
+#      malloc-ARGLIST: "void *"
+
+# - Define foo-RET as the type the function returns.  Skip if the function
+#   returns void.  One could even skip foo-ARGLIST if the function does not
+#   take any inputs AND the function returns void.
+
+
+# - Make a file called `foo-inputs` with one input value per line, an input
+#   being a comma separated list of arguments to be passed into the function.
+#   See pow-inputs for an example.
+
+subdir := benchtests
+bench := exp pow
+
+exp-ITER = 100000
+exp-ARGLIST = double
+exp-RET = double
+LDFLAGS-bench-exp = -lm
+
+pow-ITER = 100000
+pow-ARGLIST = double:double
+pow-RET = double
+LDFLAGS-bench-pow = -lm
+
+include ../Makeconfig
+include ../Rules
diff --git a/benchtests/bench-skeleton.c b/benchtests/bench-skeleton.c
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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;
+}
diff --git a/benchtests/exp-inputs b/benchtests/exp-inputs
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index 0000000000..a2086baa86
--- /dev/null
+++ b/benchtests/exp-inputs
@@ -0,0 +1 @@
+708.00096423260981737257679924368858
diff --git a/benchtests/pow-inputs b/benchtests/pow-inputs
new file mode 100644
index 0000000000..dbb1270b75
--- /dev/null
+++ b/benchtests/pow-inputs
@@ -0,0 +1 @@
+1.0000000000000020, 1.5