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43fe811b73
HP_TIMING uses native timestamping instructions if available, thus greatly reducing the overhead of recording start and end times for function calls. For architectures that don't have HP_TIMING available, we fall back to the clock_gettime bits. One may also override this by invoking the benchmark as follows: make USE_CLOCK_GETTIME=1 bench and get the benchmark results using clock_gettime. One has to do `make bench-clean` to ensure that the benchmark programs are rebuilt.
111 lines
2.8 KiB
C
111 lines
2.8 KiB
C
/* Skeleton for benchmark programs.
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Copyright (C) 2013 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <string.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <time.h>
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#include <inttypes.h>
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#include "bench-timing.h"
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volatile unsigned int dontoptimize = 0;
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void
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startup (void)
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{
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/* This loop should cause CPU to switch to maximal freqency.
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This makes subsequent measurement more accurate. We need a side effect
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to prevent the loop being deleted by compiler.
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This should be enough to cause CPU to speed up and it is simpler than
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running loop for constant time. This is used when user does not have root
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access to set a constant freqency. */
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for (int k = 0; k < 10000000; k++)
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dontoptimize += 23 * dontoptimize + 2;
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}
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#define TIMESPEC_AFTER(a, b) \
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(((a).tv_sec == (b).tv_sec) ? \
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((a).tv_nsec > (b).tv_nsec) : \
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((a).tv_sec > (b).tv_sec))
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int
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main (int argc, char **argv)
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{
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unsigned long i, k;
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struct timespec runtime;
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timing_t start, end;
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startup();
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memset (&runtime, 0, sizeof (runtime));
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unsigned long iters;
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TIMING_INIT (iters);
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for (int v = 0; v < NUM_VARIANTS; v++)
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{
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/* Run for approximately DURATION seconds. */
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clock_gettime (CLOCK_MONOTONIC_RAW, &runtime);
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runtime.tv_sec += DURATION;
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double d_total_i = 0;
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timing_t total = 0, max = 0, min = 0x7fffffffffffffff;
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while (1)
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{
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for (i = 0; i < NUM_SAMPLES (v); i++)
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{
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uint64_t cur;
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TIMING_NOW (start);
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for (k = 0; k < iters; k++)
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BENCH_FUNC (v, i);
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TIMING_NOW (end);
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TIMING_DIFF (cur, start, end);
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if (cur > max)
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max = cur;
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if (cur < min)
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min = cur;
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TIMING_ACCUM (total, cur);
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d_total_i += iters;
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}
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struct timespec curtime;
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memset (&curtime, 0, sizeof (curtime));
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clock_gettime (CLOCK_MONOTONIC_RAW, &curtime);
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if (TIMESPEC_AFTER (curtime, runtime))
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goto done;
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}
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double d_total_s;
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double d_iters;
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done:
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d_total_s = total;
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d_iters = iters;
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TIMING_PRINT_STATS (VARIANT (v), d_total_s, d_iters, d_total_i, max,
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min);
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}
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return 0;
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}
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