test/service: use compiler atomics for lock sync

Convert rte_atomic usages to compiler atomic built-ins for lock
sync in service_cores testcases.

Signed-off-by: Joyce Kong <joyce.kong@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>

diff --git a/app/test/test_service_cores.c b/app/test/test_service_cores.c
index 37d7172..ece1040 100644 (file)
--- a/app/test/test_service_cores.c
+++ b/app/test/test_service_cores.c
@@ -53,18 +53,20 @@ static int32_t dummy_cb(void *args)
 static int32_t dummy_mt_unsafe_cb(void *args)
 {
        /* before running test, the initialization has set pass_test to 1.
-        * If the cmpset in service-cores is working correctly, the code here
+        * If the CAS in service-cores is working correctly, the code here
         * should never fail to take the lock. If the lock *is* taken, fail the
         * test, because two threads are concurrently in a non-MT safe callback.
         */
        uint32_t *test_params = args;
-       uint32_t *atomic_lock = &test_params[0];
+       uint32_t *lock = &test_params[0];
        uint32_t *pass_test = &test_params[1];
-       int lock_taken = rte_atomic32_cmpset(atomic_lock, 0, 1);
+       uint32_t exp = 0;
+       int lock_taken = __atomic_compare_exchange_n(lock, &exp, 1, 0,
+                                       __ATOMIC_RELAXED, __ATOMIC_RELAXED);
        if (lock_taken) {
                /* delay with the lock held */
                rte_delay_ms(250);
-               rte_atomic32_clear((rte_atomic32_t *)atomic_lock);
+               __atomic_store_n(lock, 0, __ATOMIC_RELAXED);
        } else {
                /* 2nd thread will fail to take lock, so set pass flag */
                *pass_test = 0;
@@ -83,13 +85,15 @@ static int32_t dummy_mt_safe_cb(void *args)
         *    that 2 threads are running the callback at the same time: MT safe
         */
        uint32_t *test_params = args;
-       uint32_t *atomic_lock = &test_params[0];
+       uint32_t *lock = &test_params[0];
        uint32_t *pass_test = &test_params[1];
-       int lock_taken = rte_atomic32_cmpset(atomic_lock, 0, 1);
+       uint32_t exp = 0;
+       int lock_taken = __atomic_compare_exchange_n(lock, &exp, 1, 0,
+                                       __ATOMIC_RELAXED, __ATOMIC_RELAXED);
        if (lock_taken) {
                /* delay with the lock held */
                rte_delay_ms(250);
-               rte_atomic32_clear((rte_atomic32_t *)atomic_lock);
+               __atomic_store_n(lock, 0, __ATOMIC_RELAXED);
        } else {
                /* 2nd thread will fail to take lock, so set pass flag */
                *pass_test = 1;
@@ -622,9 +626,9 @@ service_threaded_test(int mt_safe)
        TEST_ASSERT_EQUAL(0, rte_service_lcore_add(slcore_2),
                        "mt safe lcore add fail");
 
-       /* Use atomic locks to verify that two threads are in the same function
-        * at the same time. These are passed to the unit tests through the
-        * callback userdata parameter
+       /* Use locks to verify that two threads are in the same function
+        * at the same time. These are passed to the unit tests through
+        * the callback userdata parameter.
         */
        uint32_t test_params[2];
        memset(test_params, 0, sizeof(uint32_t) * 2);
@@ -713,7 +717,7 @@ service_mt_safe_poll(void)
 }
 
 /* tests a NON mt safe service with two cores, the callback is serialized
- * using the atomic cmpset.
+ * using the CAS.
  */
 static int
 service_mt_unsafe_poll(void)
@@ -735,17 +739,17 @@ delay_as_a_mt_safe_service(void *args)
        RTE_SET_USED(args);
        uint32_t *params = args;
 
-       /* retrieve done flag and atomic lock to inc/dec */
+       /* retrieve done flag and lock to add/sub */
        uint32_t *done = &params[0];
-       rte_atomic32_t *lock = (rte_atomic32_t *)&params[1];
+       uint32_t *lock = &params[1];
 
        while (!*done) {
-               rte_atomic32_inc(lock);
+               __atomic_add_fetch(lock, 1, __ATOMIC_RELAXED);
                rte_delay_us(500);
-               if (rte_atomic32_read(lock) > 1)
+               if (__atomic_load_n(lock, __ATOMIC_RELAXED) > 1)
                        /* pass: second core has simultaneously incremented */
                        *done = 1;
-               rte_atomic32_dec(lock);
+               __atomic_sub_fetch(lock, 1, __ATOMIC_RELAXED);
        }
 
        return 0;