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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (c) 2017 Richard Palethorpe <rpalethorpe@suse.com>
*/
/* Basic functionality test for tst_fuzzy_sync.h similar to the atomic tests
* (test15.c). One thread writes to the odd indexes of an array while the
* other writes to the even. If the threads are not synchronised then they
* will probably write to the wrong indexes as they share an index variable
* which they should take it in turns to update.
*/
#include <stdlib.h>
#include "tst_test.h"
#include "tst_safe_pthread.h"
#include "tst_fuzzy_sync.h"
/* LOOPS * 2 + 1 must be less than INT_MAX */
#define LOOPS 0xFFFFULL
static volatile char seq[LOOPS * 2 + 1];
static struct tst_fzsync_pair pair;
static volatile int seq_n;
static volatile char last_wins;
static void setup(void)
{
pair.exec_loops = LOOPS;
tst_fzsync_pair_init(&pair);
}
static void *worker(void *v LTP_ATTRIBUTE_UNUSED)
{
unsigned long long i;
for (i = 0; tst_fzsync_run_b(&pair); i++) {
tst_fzsync_start_race_b(&pair);
usleep(1);
last_wins = 'B';
tst_fzsync_end_race_b(&pair);
seq[seq_n] = 'B';
seq_n = (i + 1) * 2 % (int)LOOPS * 2;
}
if (i != LOOPS) {
tst_res(TFAIL,
"Worker performed wrong number of iterations: %lld != %lld",
i, LOOPS);
}
return NULL;
}
static void run(void)
{
unsigned int i, j, fail = 0, lost_race = 0;
tst_fzsync_pair_reset(&pair, worker);
for (i = 0; tst_fzsync_run_a(&pair); i++) {
tst_fzsync_start_race_a(&pair);
seq[seq_n] = 'A';
seq_n = i * 2 + 1;
last_wins = 'A';
tst_fzsync_end_race_a(&pair);
if (last_wins == 'B')
lost_race++;
}
tst_res(TINFO, "Checking sequence...");
for (i = 0; i < LOOPS; i++) {
j = i * 2;
if (seq[j] != 'A') {
tst_res(TFAIL, "Expected A, but found %c at %d",
seq[j], j);
fail = 1;
}
j = i * 2 + 1;
if (seq[j] != 'B') {
tst_res(TFAIL, "Expected A, but found %c at %d",
seq[j], j);
fail = 1;
}
}
if (!fail)
tst_res(TPASS, "Sequence is correct");
if (lost_race < 100)
tst_res(TFAIL, "A only lost the race %d times", lost_race);
else
tst_res(TPASS, "A lost the race %d times", lost_race);
}
static void cleanup(void)
{
tst_fzsync_pair_cleanup(&pair);
}
static struct tst_test test = {
.setup = setup,
.cleanup = cleanup,
.test_all = run,
};