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/*
* Copyright 2011-2015 Samy Al Bahra.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <ck_cc.h>
#include <ck_sequence.h>
#include <errno.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include "../../common.h"
#ifndef STEPS
#define STEPS 1000000
#endif
struct example {
unsigned int a;
unsigned int b;
unsigned int c;
};
static struct example global CK_CC_CACHELINE;
static ck_sequence_t seqlock CK_CC_CACHELINE = CK_SEQUENCE_INITIALIZER;
static unsigned int barrier;
static struct affinity affinerator;
static void
validate(struct example *copy)
{
if (copy->b != copy->a + 1000) {
ck_error("ERROR: Failed regression: copy->b (%u != %u + %u / %u)\n",
copy->b, copy->a, 1000, copy->a + 1000);
}
if (copy->c != copy->a + copy->b) {
ck_error("ERROR: Failed regression: copy->c (%u != %u + %u / %u)\n",
copy->c, copy->a, copy->b, copy->a + copy->b);
}
return;
}
static void *
consumer(void *unused CK_CC_UNUSED)
{
struct example copy;
uint32_t version;
unsigned int retries = 0;
unsigned int i;
unused = NULL;
if (aff_iterate(&affinerator)) {
perror("ERROR: Could not affine thread");
exit(EXIT_FAILURE);
}
while (ck_pr_load_uint(&barrier) == 0);
for (i = 0; i < STEPS; i++) {
/*
* Attempt a read of the data structure. If the structure
* has been modified between ck_sequence_read_begin and
* ck_sequence_read_retry then attempt another read since
* the data may be in an inconsistent state.
*/
do {
version = ck_sequence_read_begin(&seqlock);
copy.a = ck_pr_load_uint(&global.a);
copy.b = ck_pr_load_uint(&global.b);
copy.c = ck_pr_load_uint(&global.c);
retries++;
} while (ck_sequence_read_retry(&seqlock, version) == true);
validate(©);
CK_SEQUENCE_READ(&seqlock, &version) {
copy.a = ck_pr_load_uint(&global.a);
copy.b = ck_pr_load_uint(&global.b);
copy.c = ck_pr_load_uint(&global.c);
retries++;
}
validate(©);
}
fprintf(stderr, "%u retries.\n", retries - STEPS);
ck_pr_dec_uint(&barrier);
return (NULL);
}
int
main(int argc, char *argv[])
{
pthread_t *threads;
unsigned int counter = 0;
bool first = true;
int n_threads, i;
if (argc != 3) {
ck_error("Usage: ck_sequence <number of threads> <affinity delta>\n");
}
n_threads = atoi(argv[1]);
if (n_threads <= 0) {
ck_error("ERROR: Number of threads must be greater than 0\n");
}
threads = malloc(sizeof(pthread_t) * n_threads);
if (threads == NULL) {
ck_error("ERROR: Could not allocate memory for threads\n");
}
affinerator.delta = atoi(argv[2]);
affinerator.request = 0;
for (i = 0; i < n_threads; i++) {
if (pthread_create(&threads[i], NULL, consumer, NULL)) {
ck_error("ERROR: Failed to create thread %d\n", i);
}
}
for (;;) {
/*
* Update the shared data in a non-blocking fashion.
* If the data is modified by multiple writers then
* ck_sequence_write_begin must be called after acquiring
* the associated lock and ck_sequence_write_end must be
* called before relinquishing the lock.
*/
ck_sequence_write_begin(&seqlock);
global.a = counter++;
global.b = global.a + 1000;
global.c = global.b + global.a;
ck_sequence_write_end(&seqlock);
if (first == true) {
ck_pr_store_uint(&barrier, n_threads);
first = false;
}
counter++;
if (ck_pr_load_uint(&barrier) == 0)
break;
}
printf("%u updates made.\n", counter);
return (0);
}
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