MAPREDUCE-4478. Fixed a bug in TaskTracker's heartbeat to keep it under control. (Liyin Liang via vinodkv)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-1@1415848 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -394,6 +394,9 @@ Release 1.1.1 - Unreleased
     HADOOP-8745. Incorrect version numbers in hadoop-core POM.
     (Matthias Friedrich via eli)
 
+    MAPREDUCE-4478. Fixed a bug in TaskTracker's heartbeat to keep it under
+    control. (Liyin Liang via vinodkv)
+
 Release 1.1.0 - 2012.09.28
 
   INCOMPATIBLE CHANGES

src/mapred/org/apache/hadoop/mapred/TaskTracker.java

@@ -1734,6 +1734,11 @@ public class TaskTracker implements MRConstants, TaskUmbilicalProtocol,
         // accelerate to account for multiple finished tasks up-front
         long remaining = 
           (lastHeartbeat + getHeartbeatInterval(finishedCount.get())) - now;
+        
+        if (remaining <= 0) {
+          finishedCount.set(0);
+        }
+          
         while (remaining > 0) {
           // sleeps for the wait time or 
           // until there are *enough* empty slots to schedule tasks