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/* Copyright (C) CZ.NIC, z.s.p.o. and contributors
* SPDX-License-Identifier: GPL-2.0-or-later
* For more information, see <https://www.knot-dns.cz/>
*/
#include <pthread.h>
#include <signal.h>
#include <tap/basic.h>
#include "contrib/atomic.h"
#include "knot/server/dthreads.h"
#define THREADS 16
#if defined(HAVE_C11_ATOMIC) || defined(HAVE_GCC_ATOMIC)
#define CYCLES1 100000
#define CYCLES2 2000000
#define CYCLES3 100000
#else
// Spinlock-emulated atomics. Locking is much slower, enough collisions occur,
#define CYCLES1 50000
#define CYCLES2 100000
#define CYCLES3 100000
#endif
#define UPPER 0xffffffff00000000
#define LOWER 0x00000000ffffffff
#define UPPER_PTR ((void *) UPPER)
#define LOWER_PTR ((void *) LOWER)
static knot_atomic_uint64_t counter_add;
static knot_atomic_uint64_t counter_sub;
static knot_atomic_uint64_t atomic_var;
static knot_atomic_ptr_t atomic_var2;
static int errors = 0;
static int uppers;
static int lowers;
static int uppers_count = 0;
static int lowers_count = 0;
static pthread_mutex_t mx;
static int thread_add(struct dthread *thread)
{
for (int i = 0; i < CYCLES1; i++) {
ATOMIC_ADD(counter_add, 7);
ATOMIC_SUB(counter_sub, 7);
}
return 0;
}
static int thread_set(struct dthread *thread)
{
u_int64_t val = (dt_get_id(thread) % 2) ? UPPER : LOWER;
for (int i = 0; i < CYCLES2; i++) {
ATOMIC_SET(atomic_var, val);
volatile u_int64_t read = ATOMIC_GET(atomic_var);
if (read != UPPER && read != LOWER) {
// Non-atomic counter, won't be accurate!
// However, it's sufficient for fault detection.
errors++;
}
}
return 0;
}
static int thread_xchg(struct dthread *thread)
{
void *val = (dt_get_id(thread) % 2) ? UPPER_PTR : LOWER_PTR;
pthread_mutex_lock(&mx);
if (val == UPPER_PTR) {
uppers++;
} else {
lowers++;
};
pthread_mutex_unlock(&mx);
for (int i = 0; i < CYCLES3; i++) {
val = ATOMIC_XCHG(atomic_var2, val);
if (val != UPPER_PTR && val != LOWER_PTR) {
// Non-atomic counter, won't be accurate!
// However, it's sufficient for fault detection.
errors++;
return 0;
}
}
pthread_mutex_lock(&mx);
if (val == UPPER_PTR) {
uppers_count++;
} else if (val == LOWER_PTR) {
lowers_count++;
};
pthread_mutex_unlock(&mx);
return 0;
}
// Signal handler
static void interrupt_handle(int s)
{
}
int main(int argc, char *argv[])
{
plan_lazy();
ATOMIC_INIT(counter_add, 0);
ATOMIC_INIT(counter_sub, 0);
ATOMIC_INIT(atomic_var, 0);
ATOMIC_INIT(atomic_var2, NULL);
// Register service and signal handler
struct sigaction sa;
sa.sa_handler = interrupt_handle;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
sigaction(SIGALRM, &sa, NULL); // Interrupt
// Test for atomicity of ATOMIC_ADD and ATOMIC_SUB.
dt_unit_t *unit = dt_create(THREADS, thread_add, NULL, NULL);
dt_start(unit);
dt_join(unit);
dt_delete(&unit);
is_int(THREADS * CYCLES1 * 7, ATOMIC_GET(counter_add), "atomicity of ATOMIC_ADD");
is_int(THREADS * CYCLES1 * 7, -ATOMIC_GET(counter_sub), "atomicity of ATOMIC_SUB");
// Test for atomicity of ATOMIC_SET and ATOMIC_GET.
unit = dt_create(THREADS, thread_set, NULL, NULL);
dt_start(unit);
dt_join(unit);
dt_delete(&unit);
is_int(0, errors, "atomicity of ATOMIC_SET / ATOMIC_GET");
// Test for atomicity of ATOMIC_XCHG.
errors = 0;
uppers = 0; // Initialize in code so as to calm down Coverity.
lowers = 0; // Idem.
ATOMIC_SET(atomic_var2, UPPER_PTR);
uppers++;
pthread_mutex_init(&mx, NULL);
unit = dt_create(THREADS, thread_xchg, NULL, NULL);
dt_start(unit);
dt_join(unit);
dt_delete(&unit);
pthread_mutex_destroy(&mx);
if (ATOMIC_GET(atomic_var2) == UPPER_PTR) {
uppers_count++;
} else if (ATOMIC_GET(atomic_var2) == LOWER_PTR) {
lowers_count++;
} else {
errors++;
}
is_int(0, errors, "set/get atomicity of ATOMIC_XCHG");
is_int(uppers, uppers_count, "atomicity of ATOMIC_XCHG");
is_int(lowers, lowers_count, "atomicity of ATOMIC_XCHG");
ATOMIC_DEINIT(counter_add);
ATOMIC_DEINIT(counter_sub);
ATOMIC_DEINIT(atomic_var);
ATOMIC_DEINIT(atomic_var2);
return 0;
}
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