Minor changes based on PR comments.

Author: tdas

core/src/main/scala/org/apache/spark/storage/BlockManager.scala

@@ -820,7 +820,7 @@ private[spark] class BlockManager(
     val peersFailedToReplicateTo = new ArrayBuffer[BlockManagerId]
     val tLevel = StorageLevel(
       level.useDisk, level.useMemory, level.useOffHeap, level.deserialized, 1)
-    val startTime = System.nanoTime
+    val startTime = System.currentTimeMillis
     val random = new Random(blockId.hashCode)
 
     var replicationFailed = false
@@ -871,7 +871,7 @@ private[spark] class BlockManager(
             blockTransferService.uploadBlockSync(
               peer.host, peer.port, blockId.toString, new NioByteBufferManagedBuffer(data), tLevel)
             logTrace(s"Replicated $blockId of ${data.limit()} bytes to $peer in %f ms"
-              .format((System.currentTimeMillis - onePeerStartTime) / 1e3))
+              .format((System.currentTimeMillis - onePeerStartTime)))
             peersReplicatedTo += peer
             peersForReplication -= peer
             replicationFailed = false
@@ -892,7 +892,7 @@ private[spark] class BlockManager(
           done = true
       }
     }
-    val timeTakeMs = (System.currentTimeMillis - startTime) / 1e3
+    val timeTakeMs = (System.currentTimeMillis - startTime)
     logDebug(s"Replicating $blockId of ${data.limit()} bytes to " +
       s"${peersReplicatedTo.size} peer(s) took $timeTakeMs ms")
     if (peersReplicatedTo.size < numPeersToReplicateTo) {

core/src/main/scala/org/apache/spark/storage/BlockManagerId.scala

@@ -59,7 +59,7 @@ class BlockManagerId private (
 
   def port: Int = port_
 
-  def isDriver = (executorId == "<driver>")
+  def isDriver: Boolean = (executorId == "<driver>")
 
   override def writeExternal(out: ObjectOutput) {
     out.writeUTF(executorId_)

core/src/test/scala/org/apache/spark/storage/BlockManagerSuite.scala

@@ -1372,7 +1372,6 @@ class BlockManagerSuite extends FunSuite with Matchers with BeforeAndAfter
   }
 
   test("block replication - replication failures") {
-
     /*
       Create a system of three block managers / stores. One of them (say, failableStore)
       cannot receive blocks. So attempts to use that as replication target fails.
@@ -1383,13 +1382,12 @@ class BlockManagerSuite extends FunSuite with Matchers with BeforeAndAfter
           |                                          |
           -----/works/-----> store1 <----/fails/------
 
-        We are first going to add a normal store and a failable store, and test
-        whether 2x replication fails to create two copies of a block.
-        Then we are going to add the third normal store,
+        We are first going to add a normal block manager (i.e. store) and the failable block
+        manager (i.e. failableStore), and test whether 2x replication fails to create two
+        copies of a block. Then we are going to add another normal block manager (i.e., store1),
         and test that now 2x replication works as the new store will be used for replication.
      */
 
-
     // Insert a block with 2x replication and return the number of copies of the block
     def replicateAndGetNumCopies(blockId: String): Int = {
       store.putSingle(blockId, new Array[Byte](1000), StorageLevel.MEMORY_AND_DISK_2)
@@ -1490,7 +1488,7 @@ class BlockManagerSuite extends FunSuite with Matchers with BeforeAndAfter
       i => makeBlockManager(storeSize, s"store$i")
     }
 
-    storageLevels.foreach {storageLevel =>
+    storageLevels.foreach { storageLevel =>
       // Put the block into one of the stores
       val blockId = new TestBlockId(
         "block-with-" + storageLevel.description.replace(" ", "-").toLowerCase)