[dpdk-dev] [PATCH 4/4] test/stack: remove atomics operations

[Steven Lariau <steven.lariau@arm.com>]

Remove the part that checks if there is enough room in the stack, it's
always true as long as size of stack >= MAX_BULK*rte_lcore_count().
This check used an atomic cmpset, and read / write to a shared size
variable. These operations result in some form of synchronization
that might get in the way of the actual stack testing.

Signed-off-by: Steven Lariau <steven.lariau@arm.com>
Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
Reviewed-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
---
 app/test/test_stack.c | 23 +++--------------------
 1 file changed, 3 insertions(+), 20 deletions(-)

diff --git a/app/test/test_stack.c b/app/test/test_stack.c
index b9d6befd4..02bea7ec5 100644
--- a/app/test/test_stack.c
+++ b/app/test/test_stack.c
@@ -273,7 +273,6 @@ test_free_null(void)
 
 struct test_args {
 	struct rte_stack *s;
-	rte_atomic64_t *sz;
 };
 
 static int
@@ -284,21 +283,9 @@ stack_thread_push_pop(void *args)
 	int i;
 
 	for (i = 0; i < NUM_ITERS_PER_THREAD; i++) {
-		unsigned int success, num;
+		unsigned int num;
 
-		/* Reserve up to min(MAX_BULK, available slots) stack entries,
-		 * then push and pop those stack entries.
-		 */
-		do {
-			uint64_t sz = rte_atomic64_read(t->sz);
-			volatile uint64_t *sz_addr;
-
-			sz_addr = (volatile uint64_t *)t->sz;
-
-			num = RTE_MIN(rte_rand() % MAX_BULK, STACK_SIZE - sz);
-
-			success = rte_atomic64_cmpset(sz_addr, sz, sz + num);
-		} while (success == 0);
+		num = rte_rand() % MAX_BULK;
 
 		if (rte_stack_push(t->s, obj_table, num) != num) {
 			printf("[%s():%u] Failed to push %u pointers\n",
@@ -312,7 +299,6 @@ stack_thread_push_pop(void *args)
 			return -1;
 		}
 
-		rte_atomic64_sub(t->sz, num);
 	}
 
 	return 0;
@@ -324,7 +310,6 @@ test_stack_multithreaded(uint32_t flags)
 	struct test_args args;
 	unsigned int lcore_id;
 	struct rte_stack *s;
-	rte_atomic64_t size;
 	int result = 0;
 
 	if (rte_lcore_count() < 2) {
@@ -335,16 +320,14 @@ test_stack_multithreaded(uint32_t flags)
 	printf("[%s():%u] Running with %u lcores\n",
 	       __func__, __LINE__, rte_lcore_count());
 
-	s = rte_stack_create("test", STACK_SIZE, rte_socket_id(), flags);
+	s = rte_stack_create("test", MAX_BULK * rte_lcore_count(), rte_socket_id(), flags);
 	if (s == NULL) {
 		printf("[%s():%u] Failed to create a stack\n",
 		       __func__, __LINE__);
 		return -1;
 	}
 
-	rte_atomic64_init(&size);
 	args.s = s;
-	args.sz = &size;
 
 	if (rte_eal_mp_remote_launch(stack_thread_push_pop, &args, CALL_MASTER))
 		rte_panic("Failed to launch tests\n");
-- 
2.17.1