MINOR: queues: use __ha_cpu_relax() on failed CAS.

Make sure we call __ha_cpu_relax() if we fail a CAS, to help with
contention.

diff --git a/src/queue.c b/src/queue.c
index 0bfdd09f026e5de6794f6233d1f01ffaac8b6db3..2e8e861a57b06f35ba319f3b22ad69dcbfd50ebc 100644 (file)
--- a/src/queue.c
+++ b/src/queue.c
@@ -453,7 +453,7 @@ int process_srv_queue(struct server *s)
                                        else
                                                new_served++;
                                }
-                       } while (!_HA_ATOMIC_CAS(&s->per_tgrp[tgid - 1].last_other_tgrp_served, &old_served, new_served));
+                       } while (!_HA_ATOMIC_CAS(&s->per_tgrp[tgid - 1].last_other_tgrp_served, &old_served, new_served) && __ha_cpu_relax());
                        cur_tgrp = new_served;
                        to_dequeue = 1;
                } else {