Revert "HBASE-15967 Metric for active ipc Readers and make default fraction of cpu count"

Revert mistaken commit
This reverts commit 1125215aad.

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/ipc/MetricsHBaseServerSource.java

@@ -86,13 +86,6 @@ public interface MetricsHBaseServerSource extends BaseSource {
   String EXCEPTIONS_MULTI_TOO_LARGE_DESC = "A response to a multi request was too large and the " +
       "rest of the requests will have to be retried.";
 
-  String RUNNING_READERS = "runningReaders";
-  String RUNNING_READERS_DESCRIPTION =
-      "Count of Reader threads currently busy parsing requests to hand off to the scheduler";
-
-  void incrRunningReaders();
-  void decrRunningReaders();
-
   void authorizationSuccess();
 
   void authorizationFailure();
@@ -129,4 +122,6 @@ public interface MetricsHBaseServerSource extends BaseSource {
   void processedCall(int processingTime);
 
   void queuedAndProcessedCall(int totalTime);
-}
+
+
+}

hbase-hadoop2-compat/src/main/java/org/apache/hadoop/hbase/ipc/MetricsHBaseServerSourceImpl.java

@@ -57,12 +57,6 @@ public class MetricsHBaseServerSourceImpl extends BaseSourceImpl
   private MetricHistogram requestSize;
   private MetricHistogram responseSize;
 
-  /**
-   * The count of readers currently working parsing a request as opposed to being blocked on the
-   * selector waiting on requests to come in.
-   */
-  private final MutableFastCounter runningReaders;
-
   public MetricsHBaseServerSourceImpl(String metricsName,
                                       String metricsDescription,
                                       String metricsContext,
@@ -92,9 +86,6 @@ public class MetricsHBaseServerSourceImpl extends BaseSourceImpl
     this.exceptionsMultiTooLarge = this.getMetricsRegistry()
         .newCounter(EXCEPTIONS_MULTI_TOO_LARGE_NAME, EXCEPTIONS_MULTI_TOO_LARGE_DESC, 0L);
 
-    this.runningReaders = this.getMetricsRegistry()
-        .newCounter(RUNNING_READERS, RUNNING_READERS_DESCRIPTION, 0L);
-
     this.authenticationSuccesses = this.getMetricsRegistry().newCounter(
         AUTHENTICATION_SUCCESSES_NAME, AUTHENTICATION_SUCCESSES_DESC, 0L);
     this.authenticationFailures = this.getMetricsRegistry().newCounter(AUTHENTICATION_FAILURES_NAME,
@@ -117,16 +108,6 @@ public class MetricsHBaseServerSourceImpl extends BaseSourceImpl
               RESPONSE_SIZE_DESC);
   }
 
-  @Override
-  public void incrRunningReaders() {
-    this.runningReaders.incr(+1);
-  }
-
-  @Override
-  public void decrRunningReaders() {
-    this.runningReaders.incr(-1);
-  }
-
   @Override
   public void authorizationSuccess() {
     authorizationSuccesses.incr();

hbase-server/src/main/java/org/apache/hadoop/hbase/ipc/RpcServer.java

@@ -625,8 +625,7 @@ public class RpcServer implements RpcServerInterface, ConfigurationObserver {
 
     public Listener(final String name) throws IOException {
       super(name);
-      // The backlog of requests that we will have the serversocket carry. It is not enough
+      // The backlog of requests that we will have the serversocket carry.
-      // just setting this config. You need to set the backlog in the kernel too.
       int backlogLength = conf.getInt("hbase.ipc.server.listen.queue.size", 128);
       // Create a new server socket and set to non blocking mode
       acceptChannel = ServerSocketChannel.open();
@@ -691,12 +690,7 @@ public class RpcServer implements RpcServerInterface, ConfigurationObserver {
               iter.remove();
               if (key.isValid()) {
                 if (key.isReadable()) {
-                  metrics.getMetricsSource().incrRunningReaders();
+                  doRead(key);
-                  try {
-                    doRead(key);
-                  } finally {
-                    metrics.getMetricsSource().decrRunningReaders();
-                  }
                 }
               }
               key = null;
@@ -740,9 +734,8 @@ public class RpcServer implements RpcServerInterface, ConfigurationObserver {
             iter.remove();
             try {
               if (key.isValid()) {
-                if (key.isAcceptable()) {
+                if (key.isAcceptable())
                   doAccept(key);
-                }
               }
             } catch (IOException ignored) {
               if (LOG.isTraceEnabled()) LOG.trace("ignored", ignored);
@@ -837,8 +830,7 @@ public class RpcServer implements RpcServerInterface, ConfigurationObserver {
       try {
         count = c.readAndProcess();
       } catch (InterruptedException ieo) {
-        LOG.info(Thread.currentThread().getName() +
+        LOG.info(Thread.currentThread().getName() + ": readAndProcess caught InterruptedException", ieo);
-            ": readAndProcess caught InterruptedException", ieo);
         throw ieo;
       } catch (Exception e) {
         if (LOG.isDebugEnabled()) {
@@ -1167,7 +1159,6 @@ public class RpcServer implements RpcServerInterface, ConfigurationObserver {
     private ByteBuffer dataLengthBuffer;
     protected final ConcurrentLinkedDeque<Call> responseQueue = new ConcurrentLinkedDeque<Call>();
     private final Lock responseWriteLock = new ReentrantLock();
-    // EXPENSIVE: Counters cost lots of CPU. Remove. Used just to see if idle or not. Use boolean.
     private Counter rpcCount = new Counter(); // number of outstanding rpcs
     private long lastContact;
     private InetAddress addr;
@@ -2009,11 +2000,7 @@ public class RpcServer implements RpcServerInterface, ConfigurationObserver {
     // See declaration above for documentation on what this size is.
     this.maxQueueSizeInBytes =
       this.conf.getLong("hbase.ipc.server.max.callqueue.size", DEFAULT_MAX_CALLQUEUE_SIZE);
-    // Have the Reader thread count default to 1/4 of the processors. This seems to do pretty
+    this.readThreads = conf.getInt("hbase.ipc.server.read.threadpool.size", 10);
-    // well. See the metric hbase.regionserver.ipc.runningReaders to see if you need to change it.
-    int processors = Runtime.getRuntime().availableProcessors();
-    this.readThreads = conf.getInt("hbase.ipc.server.read.threadpool.size",
-        Math.max(8, processors/ 4));
     this.purgeTimeout = conf.getLong("hbase.ipc.client.call.purge.timeout",
       2 * HConstants.DEFAULT_HBASE_RPC_TIMEOUT);
     this.warnResponseTime = conf.getInt(WARN_RESPONSE_TIME, DEFAULT_WARN_RESPONSE_TIME);