From 95e0ac43e9791c1981b8687940c5149234386108 Mon Sep 17 00:00:00 2001
From: Patrik Nordwall <patrik.nordwall@gmail.com>
Date: Thu, 2 Nov 2017 18:26:16 +0100
Subject: [PATCH] small perf improvement of isGossipSpeedupNeeded for single-dc

---
 .../src/main/scala/akka/cluster/ClusterDaemon.scala       | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/akka-cluster/src/main/scala/akka/cluster/ClusterDaemon.scala b/akka-cluster/src/main/scala/akka/cluster/ClusterDaemon.scala
index 8399fafaea..8688024bbe 100644
--- a/akka-cluster/src/main/scala/akka/cluster/ClusterDaemon.scala
+++ b/akka-cluster/src/main/scala/akka/cluster/ClusterDaemon.scala
@@ -945,8 +945,12 @@ private[cluster] class ClusterCoreDaemon(publisher: ActorRef) extends Actor with
   def gossipSpeedupTick(): Unit =
     if (isGossipSpeedupNeeded) gossip()
 
-  def isGossipSpeedupNeeded: Boolean =
-    latestGossip.overview.seen.count(membershipState.isInSameDc) < latestGossip.members.count(_.dataCenter == cluster.selfDataCenter) / 2
+  def isGossipSpeedupNeeded: Boolean = {
+    if (latestGossip.isMultiDc)
+      latestGossip.overview.seen.count(membershipState.isInSameDc) < latestGossip.members.count(_.dataCenter == cluster.selfDataCenter) / 2
+    else
+      (latestGossip.overview.seen.size < latestGossip.members.size / 2)
+  }
 
   /**
    * Sends full gossip to `n` other random members.