HDFS-7491. Add incremental blockreport latency to DN metrics. Contributed by Ming Ma.

hadoop-common-project/hadoop-common/src/site/markdown/Metrics.md

@@ -303,6 +303,8 @@ Each metrics record contains tags such as SessionId and Hostname as additional i
 | `HeartbeatsAvgTime` | Average heartbeat time in milliseconds |
 | `BlockReportsNumOps` | Total number of block report operations |
 | `BlockReportsAvgTime` | Average time of block report operations in milliseconds |
+| `IncrementalBlockReportsNumOps` | Total number of incremental block report operations |
+| `IncrementalBlockReportsAvgTime` | Average time of incremental block report operations in milliseconds |
 | `CacheReportsNumOps` | Total number of cache report operations |
 | `CacheReportsAvgTime` | Average time of cache report operations in milliseconds |
 | `PacketAckRoundTripTimeNanosNumOps` | Total number of ack round trip |

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -740,6 +740,9 @@ Release 2.7.0 - UNRELEASED
     HDFS-6806. HDFS Rolling upgrade document should mention the versions
     available. (J.Andreina via aajisaka)
 
+    HDFS-7491. Add incremental blockreport latency to DN metrics.
+    (Ming Ma via cnauroth)
+
   OPTIMIZATIONS
 
     HDFS-7454. Reduce memory footprint for AclEntries in NameNode.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BPServiceActor.java

@@ -291,12 +291,14 @@ class BPServiceActor implements Runnable {
 
     // Send incremental block reports to the Namenode outside the lock
     boolean success = false;
+    final long startTime = Time.monotonicNow();
     try {
       bpNamenode.blockReceivedAndDeleted(bpRegistration,
           bpos.getBlockPoolId(),
           reports.toArray(new StorageReceivedDeletedBlocks[reports.size()]));
       success = true;
     } finally {
+      dn.getMetrics().addIncrementalBlockReport(Time.monotonicNow()-startTime);
       if (!success) {
         synchronized (pendingIncrementalBRperStorage) {
           for (StorageReceivedDeletedBlocks report : reports) {

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/metrics/DataNodeMetrics.java

@@ -107,6 +107,7 @@ public class DataNodeMetrics {
   @Metric MutableRate replaceBlockOp;
   @Metric MutableRate heartbeats;
   @Metric MutableRate blockReports;
+  @Metric MutableRate incrementalBlockReports;
   @Metric MutableRate cacheReports;
   @Metric MutableRate packetAckRoundTripTimeNanos;
   final MutableQuantiles[] packetAckRoundTripTimeNanosQuantiles;
@@ -201,6 +202,10 @@ public class DataNodeMetrics {
     blockReports.add(latency);
   }
 
+  public void addIncrementalBlockReport(long latency) {
+    incrementalBlockReports.add(latency);
+  }
+
   public void addCacheReport(long latency) {
     cacheReports.add(latency);
   }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestDataNodeMetrics.java

@@ -72,6 +72,8 @@ public class TestDataNodeMetrics {
       DataNode datanode = datanodes.get(0);
       MetricsRecordBuilder rb = getMetrics(datanode.getMetrics().name());
       assertCounter("BytesWritten", LONG_FILE_LEN, rb);
+      assertTrue("Expected non-zero number of incremental block reports",
+          getLongCounter("IncrementalBlockReportsNumOps", rb) > 0);
     } finally {
       if (cluster != null) {cluster.shutdown();}
     }