glibc/benchtests/bench-skeleton.c
Siddhesh Poyarekar f0ee064b7d Allow multiple input domains to be run in the same benchmark program
Some math functions have distinct performance characteristics in
specific domains of inputs, where some inputs return via a fast path
while other inputs require multiple precision calculations, that too
at different precision levels.  The way to implement different domains
was to have a separate source file and benchmark definition, resulting
in separate programs.

This clutters up the benchmark, so this change allows these domains to
be consolidated into the same input file.  To do this, the input file
format is now enhanced to allow comments with a preceding # and
directives with two # at the begining of a line.  A directive that
looks like:

tells the benchmark generation script that what follows is a different
domain of inputs.  The value of the 'name' directive (in this case,
foo) is used in the output.  The two input domains are then executed
sequentially and their results collated separately.  with the above
directive, there would be two lines in the result that look like:

func(): ....
func(foo): ...
2013-04-30 14:17:57 +05:30

101 lines
2.9 KiB
C

/* 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>
#define TIMESPEC_AFTER(a, b) \
(((a).tv_sec == (b).tv_sec) ? \
((a).tv_nsec > (b).tv_nsec) : \
((a).tv_sec > (b).tv_sec))
int
main (int argc, char **argv)
{
unsigned long i, k;
struct timespec start, end, runtime;
memset (&runtime, 0, sizeof (runtime));
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;
for (int v = 0; v < NUM_VARIANTS; v++)
{
/* Run for approximately DURATION seconds. */
clock_gettime (CLOCK_MONOTONIC_RAW, &runtime);
runtime.tv_sec += DURATION;
double d_total_i = 0;
uint64_t total = 0, max = 0, min = 0x7fffffffffffffff;
while (1)
{
for (i = 0; i < NUM_SAMPLES (v); i++)
{
clock_gettime (CLOCK_PROCESS_CPUTIME_ID, &start);
for (k = 0; k < iters; k++)
BENCH_FUNC (v, 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;
d_total_i += iters;
}
struct timespec curtime;
memset (&curtime, 0, sizeof (curtime));
clock_gettime (CLOCK_MONOTONIC_RAW, &curtime);
if (TIMESPEC_AFTER (curtime, runtime))
goto done;
}
double d_total_s;
double d_iters;
done:
d_total_s = total * 1e-9;
d_iters = iters;
printf ("%s: ITERS:%g: TOTAL:%gs, MAX:%gns, MIN:%gns, %g iter/s\n",
VARIANT (v),
d_total_i, d_total_s, max / d_iters, min / d_iters,
d_total_i / d_total_s);
}
return 0;
}