HDFS-16917 Add transfer rate quantile metrics for DataNode reads

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

@@ -370,6 +370,9 @@ Each metrics record contains tags such as SessionId and Hostname as additional i
 |:---- |:---- |
 | `BytesWritten` | Total number of bytes written to DataNode |
 | `BytesRead` | Total number of bytes read from DataNode |
+| `ReadTransferRateNumOps` | Total number of data read transfers |
+| `ReadTransferRateAvgTime` | Average transfer rate of bytes read from DataNode, measured in bytes per second. |
+| `ReadTransferRate`*num*`s(50/75/90/95/99)thPercentileRate` | The 50/75/90/95/99th percentile of the transfer rate of bytes read from DataNode, measured in bytes per second. |
 | `BlocksWritten` | Total number of blocks written to DataNode |
 | `BlocksRead` | Total number of blocks read from DataNode |
 | `BlocksReplicated` | Total number of blocks replicated |

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

@@ -632,6 +632,11 @@ public void readBlock(final ExtendedBlock block,
       datanode.metrics.incrBytesRead((int) read);
       datanode.metrics.incrBlocksRead();
       datanode.metrics.incrTotalReadTime(duration);
+      if (read < 0 || duration <= 0) {
+        LOG.warn("Unexpected value for data transfer bytes={} duration={}", read, duration);
+      } else {
+        datanode.metrics.addReadTransferRate(read * 1000 / duration);
+      }
     } catch ( SocketException ignored ) {
       LOG.trace("{}:Ignoring exception while serving {} to {}",
           dnR, block, remoteAddress, ignored);
@@ -1122,6 +1127,11 @@ public void copyBlock(final ExtendedBlock block,
       datanode.metrics.incrBytesRead((int) read);
       datanode.metrics.incrBlocksRead();
       datanode.metrics.incrTotalReadTime(duration);
+      if (read < 0 || duration <= 0) {
+        LOG.warn("Unexpected value for data transfer bytes={} duration={}", read, duration);
+      } else {
+        datanode.metrics.addReadTransferRate(read * 1000 / duration);
+      }
 
       LOG.info("Copied {} to {}", block, peer.getRemoteAddressString());
     } catch (IOException ioe) {

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

@@ -61,6 +61,8 @@ public class DataNodeMetrics {
   @Metric MutableCounterLong bytesRead;
   @Metric("Milliseconds spent reading")
   MutableCounterLong totalReadTime;
+  @Metric private MutableRate readTransferRate;
+  final private MutableQuantiles[] readTransferRateQuantiles;
   @Metric MutableCounterLong blocksWritten;
   @Metric MutableCounterLong blocksRead;
   @Metric MutableCounterLong blocksReplicated;
@@ -227,6 +229,7 @@ public DataNodeMetrics(String name, String sessionId, int[] intervals,
     sendDataPacketTransferNanosQuantiles = new MutableQuantiles[len];
     ramDiskBlocksEvictionWindowMsQuantiles = new MutableQuantiles[len];
     ramDiskBlocksLazyPersistWindowMsQuantiles = new MutableQuantiles[len];
+    readTransferRateQuantiles = new MutableQuantiles[len];
 
     for (int i = 0; i < len; i++) {
       int interval = intervals[i];
@@ -255,6 +258,10 @@ public DataNodeMetrics(String name, String sessionId, int[] intervals,
           "ramDiskBlocksLazyPersistWindows" + interval + "s",
           "Time between the RamDisk block write and disk persist in ms",
           "ops", "latency", interval);
+      readTransferRateQuantiles[i] = registry.newQuantiles(
+          "readTransferRate" + interval + "s",
+          "Rate at which bytes are read from datanode calculated in bytes per second",
+          "ops", "rate", interval);
     }
   }
 
@@ -316,6 +323,13 @@ public void addIncrementalBlockReport(long latency,
     }
   }
 
+  public void addReadTransferRate(long readTransferRate) {
+    this.readTransferRate.add(readTransferRate);
+    for (MutableQuantiles q : readTransferRateQuantiles) {
+      q.add(readTransferRate);
+    }
+  }
+
   public void addCacheReport(long latency) {
     cacheReports.add(latency);
   }

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

@@ -380,6 +380,7 @@ public void testTimeoutMetric() throws Exception {
   @Test(timeout=120000)
   public void testDataNodeTimeSpend() throws Exception {
     Configuration conf = new HdfsConfiguration();
+    conf.set(DFSConfigKeys.DFS_METRICS_PERCENTILES_INTERVALS_KEY, "" + 60);
     MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf).build();
     try {
       final FileSystem fs = cluster.getFileSystem();
@@ -391,6 +392,7 @@ public void testDataNodeTimeSpend() throws Exception {
 
       final long startWriteValue = getLongCounter("TotalWriteTime", rb);
       final long startReadValue = getLongCounter("TotalReadTime", rb);
+      assertCounter("ReadTransferRateNumOps", 0L, rb);
       final AtomicInteger x = new AtomicInteger(0);
 
       // Lets Metric system update latest metrics
@@ -410,6 +412,8 @@ public Boolean get() {
           MetricsRecordBuilder rbNew = getMetrics(datanode.getMetrics().name());
           final long endWriteValue = getLongCounter("TotalWriteTime", rbNew);
           final long endReadValue = getLongCounter("TotalReadTime", rbNew);
+          assertCounter("ReadTransferRateNumOps", 1L, rbNew);
+          assertQuantileGauges("ReadTransferRate" + "60s", rbNew, "Rate");
           return endWriteValue > startWriteValue
               && endReadValue > startReadValue;
         }