glibc/benchtests/bench-pthread-lock-base.c

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/* Measure lock functions for different threads and critical sections.
Copyright (C) 2022-2024 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
<https://www.gnu.org/licenses/>. */
#define TEST_MAIN
#define TIMEOUT (20 * 60)
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <math.h>
#include <pthread.h>
#include <sys/time.h>
#include <sys/sysinfo.h>
#include "bench-timing.h"
#include "json-lib.h"
static bench_lock_t lock;
static bench_lock_attr_t attr;
static pthread_barrier_t barrier;
#define START_ITERS 1000
#pragma GCC push_options
#pragma GCC optimize(1)
static int __attribute__ ((noinline)) fibonacci (int i)
{
asm("");
if (i > 2)
return fibonacci (i - 1) + fibonacci (i - 2);
return 10 + i;
}
static void
do_filler (void)
{
char buf1[512], buf2[512];
int f = fibonacci (4);
memcpy (buf1, buf2, f);
}
static void
do_filler_shared (void)
{
static char buf1[512], buf2[512];
int f = fibonacci (4);
memcpy (buf1, buf2, f);
}
#pragma GCC pop_options
#define UNIT_WORK_CRT do_filler_shared ()
#define UNIT_WORK_NON_CRT do_filler ()
static inline void
critical_section (int length)
{
for (int i = length; i >= 0; i--)
UNIT_WORK_CRT;
}
static inline void
non_critical_section (int length)
{
for (int i = length; i >= 0; i--)
UNIT_WORK_NON_CRT;
}
typedef struct Worker_Params
{
long iters;
int crt_len;
int non_crt_len;
timing_t duration;
} Worker_Params;
static void *
worker (void *v)
{
timing_t start, stop;
Worker_Params *p = (Worker_Params *) v;
long iters = p->iters;
int crt_len = p->crt_len;
int non_crt_len = p->non_crt_len;
pthread_barrier_wait (&barrier);
TIMING_NOW (start);
while (iters--)
{
LOCK (&lock);
critical_section (crt_len);
UNLOCK (&lock);
non_critical_section (non_crt_len);
}
TIMING_NOW (stop);
TIMING_DIFF (p->duration, start, stop);
return NULL;
}
static double
do_one_test (int num_threads, int crt_len, int non_crt_len, long iters)
{
int i;
timing_t mean;
Worker_Params *p, params[num_threads];
pthread_t threads[num_threads];
LOCK_INIT (&lock, &attr);
pthread_barrier_init (&barrier, NULL, num_threads);
for (i = 0; i < num_threads; i++)
{
p = &params[i];
p->iters = iters;
p->crt_len = crt_len;
p->non_crt_len = non_crt_len;
pthread_create (&threads[i], NULL, worker, (void *) p);
}
for (i = 0; i < num_threads; i++)
pthread_join (threads[i], NULL);
LOCK_DESTROY (&lock);
pthread_barrier_destroy (&barrier);
mean = 0;
for (i = 0; i < num_threads; i++)
mean += params[i].duration;
mean /= num_threads;
return mean;
}
#define RUN_COUNT 10
#define MIN_TEST_SEC 0.01
static void
do_bench_one (const char *name, int num_threads, int crt_len, int non_crt_len,
json_ctx_t *js)
{
timing_t cur;
struct timeval ts, te;
double tsd, ted, td;
long iters, iters_limit, total_iters;
timing_t curs[RUN_COUNT + 2];
int i, j;
double mean, stdev;
iters = START_ITERS;
iters_limit = LONG_MAX / 100;
while (1)
{
gettimeofday (&ts, NULL);
cur = do_one_test (num_threads, crt_len, non_crt_len, iters);
gettimeofday (&te, NULL);
/* Make sure the test to run at least MIN_TEST_SEC. */
tsd = ts.tv_sec + ts.tv_usec / 1000000.0;
ted = te.tv_sec + te.tv_usec / 1000000.0;
td = ted - tsd;
if (td >= MIN_TEST_SEC || iters >= iters_limit)
break;
iters *= 10;
}
curs[0] = cur;
for (i = 1; i < RUN_COUNT + 2; i++)
curs[i] = do_one_test (num_threads, crt_len, non_crt_len, iters);
/* Sort the results so we can discard the fastest and slowest
times as outliers. */
for (i = 0; i < RUN_COUNT + 1; i++)
for (j = i + 1; j < RUN_COUNT + 2; j++)
if (curs[i] > curs[j])
{
timing_t temp = curs[i];
curs[i] = curs[j];
curs[j] = temp;
}
/* Calculate mean and standard deviation. */
mean = 0.0;
total_iters = iters * num_threads;
for (i = 1; i < RUN_COUNT + 1; i++)
mean += (double) curs[i] / (double) total_iters;
mean /= RUN_COUNT;
stdev = 0.0;
for (i = 1; i < RUN_COUNT + 1; i++)
{
double s = (double) curs[i] / (double) total_iters - mean;
stdev += s * s;
}
stdev = sqrt (stdev / (RUN_COUNT - 1));
char buf[256];
snprintf (buf, sizeof buf, "%s,non_crt_len=%d,crt_len=%d,threads=%d", name,
non_crt_len, crt_len, num_threads);
json_attr_object_begin (js, buf);
json_attr_double (js, "duration", (double) cur);
json_attr_double (js, "iterations", (double) total_iters);
json_attr_double (js, "mean", mean);
json_attr_double (js, "stdev", stdev);
json_attr_double (js, "min-outlier",
(double) curs[0] / (double) total_iters);
json_attr_double (js, "min", (double) curs[1] / (double) total_iters);
json_attr_double (js, "max",
(double) curs[RUN_COUNT] / (double) total_iters);
json_attr_double (js, "max-outlier",
(double) curs[RUN_COUNT + 1] / (double) total_iters);
json_attr_object_end (js);
}
#define TH_CONF_MAX 10
int
do_bench (void)
{
int rv = 0;
json_ctx_t json_ctx;
int i, j, k;
int th_num, th_conf, nprocs;
int threads[TH_CONF_MAX];
int crt_lens[] = { 0, 1, 2, 4, 8, 16, 32, 64, 128 };
int non_crt_lens[] = { 1, 32, 128 };
char name[128];
json_init (&json_ctx, 2, stdout);
json_attr_object_begin (&json_ctx, TEST_NAME);
/* The thread config begins from 1, and increases by 2x until nprocs.
We also wants to test over-saturation case (1.25*nprocs). */
nprocs = get_nprocs ();
th_num = 1;
for (th_conf = 0; th_conf < (TH_CONF_MAX - 2) && th_num < nprocs; th_conf++)
{
threads[th_conf] = th_num;
th_num <<= 1;
}
threads[th_conf++] = nprocs;
threads[th_conf++] = nprocs + nprocs / 4;
LOCK_ATTR_INIT (&attr);
snprintf (name, sizeof name, "type=adaptive");
for (k = 0; k < (sizeof (non_crt_lens) / sizeof (int)); k++)
{
int non_crt_len = non_crt_lens[k];
for (j = 0; j < (sizeof (crt_lens) / sizeof (int)); j++)
{
int crt_len = crt_lens[j];
for (i = 0; i < th_conf; i++)
{
th_num = threads[i];
do_bench_one (name, th_num, crt_len, non_crt_len, &json_ctx);
}
}
}
json_attr_object_end (&json_ctx);
return rv;
}
#define TEST_FUNCTION do_bench ()
#include "../test-skeleton.c"