usleep in rbtdb

lib/dns/rbtdb.c

@@ -15,6 +15,7 @@
 
 #include <inttypes.h>
 #include <stdbool.h>
+#include <unistd.h>
 
 #include <isc/atomic.h>
 #include <isc/crc64.h>
@@ -2809,6 +2810,7 @@ findnodeintree(dns_rbtdb_t *rbtdb, dns_rbt_t *tree, const dns_name_t *name,
 		 */
 		__sync_synchronize();
 		pthread_yield();
+		usleep(10000);
 		locktype = isc_rwlocktype_write;
 		RWLOCK(&rbtdb->tree_lock, locktype);
 		node = NULL;