glibc/benchtests/bench-skeleton.c
Will Newton b987c77672 benchtests: Rename argument to TIMING_INIT macro.
The TIMING_INIT macro currently sets the number of loop iterations
to 1000, which limits usefulness. Make the argument a clock
resolution value and multiply by 1000 in bench-skeleton.c instead
to allow easier reuse.

ChangeLog:

2013-09-11  Will Newton  <will.newton@linaro.org>

	* benchtests/bench-timing.h (TIMING_INIT): Rename ITERS
	parameter to RES. Remove hardcoded 1000 value.
	* benchtests/bench-skeleton.c (main): Pass RES parameter
	to TIMING_INIT and multiply result by 1000.
2013-09-11 15:18:20 +01:00

113 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>
#include "bench-timing.h"
volatile unsigned int dontoptimize = 0;
void
startup (void)
{
/* This loop should cause CPU to switch to maximal freqency.
This makes subsequent measurement more accurate. We need a side effect
to prevent the loop being deleted by compiler.
This should be enough to cause CPU to speed up and it is simpler than
running loop for constant time. This is used when user does not have root
access to set a constant freqency. */
for (int k = 0; k < 10000000; k++)
dontoptimize += 23 * dontoptimize + 2;
}
#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 runtime;
timing_t start, end;
startup();
memset (&runtime, 0, sizeof (runtime));
unsigned long iters, res;
TIMING_INIT (res);
iters = 1000 * res;
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;
timing_t total = 0, max = 0, min = 0x7fffffffffffffff;
while (1)
{
for (i = 0; i < NUM_SAMPLES (v); i++)
{
uint64_t cur;
TIMING_NOW (start);
for (k = 0; k < iters; k++)
BENCH_FUNC (v, i);
TIMING_NOW (end);
TIMING_DIFF (cur, start, end);
if (cur > max)
max = cur;
if (cur < min)
min = cur;
TIMING_ACCUM (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;
d_iters = iters;
TIMING_PRINT_STATS (VARIANT (v), d_total_s, d_iters, d_total_i, max,
min);
}
return 0;
}