diff --git a/sources/atomic.h b/sources/atomic.h
index ca2c721f..506d1226 100644
--- a/sources/atomic.h
+++ b/sources/atomic.h
@@ -75,4 +75,16 @@ static inline uint64_t od_atomic_u64_sub(od_atomic_u64_t *atomic,
 	return __sync_sub_and_fetch(atomic, value);
 }
 
+static inline uint32_t od_atomic_u32_cas(od_atomic_u32_t *atomic,
+					 uint32_t compValue, uint32_t exchValue)
+{
+	return __sync_val_compare_and_swap(atomic, compValue, exchValue);
+}
+
+static inline uint64_t od_atomic_u64_cas(od_atomic_u64_t *atomic,
+					 uint64_t compValue, uint64_t exchValue)
+{
+	return __sync_val_compare_and_swap(atomic, compValue, exchValue);
+}
+
 #endif /* ODYSSEY_ATOMIC_H */
diff --git a/sources/system.c b/sources/system.c
index 035e5e2e..a52e30d3 100644
--- a/sources/system.c
+++ b/sources/system.c
@@ -500,7 +500,7 @@ static inline void od_system(void *arg)
 	/* start worker threads */
 	od_worker_pool_t *worker_pool = system->global->worker_pool;
 	rc = od_worker_pool_start(worker_pool, system->global,
-				  instance->config.workers);
+				  (uint32_t)instance->config.workers);
 	if (rc == -1)
 		return;
 
diff --git a/sources/worker_pool.h b/sources/worker_pool.h
index c88f243a..651a3940 100644
--- a/sources/worker_pool.h
+++ b/sources/worker_pool.h
@@ -13,8 +13,8 @@ typedef struct od_worker_pool od_worker_pool_t;
 
 struct od_worker_pool {
 	od_worker_t *pool;
-	int round_robin;
-	int count;
+	od_atomic_u32_t round_robin;
+	uint32_t count;
 };
 
 static inline void od_worker_pool_init(od_worker_pool_t *pool)
@@ -24,28 +24,29 @@ static inline void od_worker_pool_init(od_worker_pool_t *pool)
 	pool->pool = NULL;
 }
 
-static inline int od_worker_pool_start(od_worker_pool_t *pool,
-				       od_global_t *global, int count)
+static inline od_retcode_t od_worker_pool_start(od_worker_pool_t *pool,
+						od_global_t *global,
+						uint32_t count)
 {
 	pool->pool = malloc(sizeof(od_worker_t) * count);
 	if (pool->pool == NULL)
 		return -1;
 	pool->count = count;
-	int i;
+	uint32_t i;
 	for (i = 0; i < count; i++) {
 		od_worker_t *worker = &pool->pool[i];
 		od_worker_init(worker, global, i);
 		int rc;
 		rc = od_worker_start(worker);
 		if (rc == -1)
-			return -1;
+			return NOT_OK_RESPONSE;
 	}
 	return 0;
 }
 
 static inline void od_worker_pool_stop(od_worker_pool_t *pool)
 {
-	for (int i = 0; i < pool->count; i++) {
+	for (uint32_t i = 0; i < pool->count; i++) {
 		od_worker_t *worker = &pool->pool[i];
 		machine_stop(worker->machine);
 	}
@@ -63,7 +64,7 @@ od_worker_pool_wait_gracefully_shutdown(od_worker_pool_t *pool)
 	// waiting
 	//	// No new TLS handshakes should be initiated, so, just wait a bit.
 	//	machine_sleep(1);
-	for (int i = 0; i < pool->count; i++) {
+	for (uint32_t i = 0; i < pool->count; i++) {
 		od_worker_t *worker = &pool->pool[i];
 		int rc = machine_wait(worker->machine);
 		if (rc != MM_OK_RETCODE)
@@ -74,12 +75,17 @@ od_worker_pool_wait_gracefully_shutdown(od_worker_pool_t *pool)
 static inline void od_worker_pool_feed(od_worker_pool_t *pool,
 				       machine_msg_t *msg)
 {
-	int next = pool->round_robin;
-	if (pool->round_robin >= pool->count) {
-		pool->round_robin = 0;
-		next = 0;
+	uint32_t next;
+	uint32_t oldValue;
+
+	while (1) {
+		oldValue = od_atomic_u32_of(&pool->round_robin);
+		next = oldValue + 1 == pool->count ? 0 : oldValue;
+
+		if (od_atomic_u32_cas(&pool->round_robin, oldValue, next) ==
+		    oldValue)
+			break;
 	}
-	pool->round_robin++;
 
 	od_worker_t *worker;
 	worker = &pool->pool[next];