Fixed negative value in perf counter

git-svn-id: https://hyracks.googlecode.com/svn/branches/hyracks_dev_next@1004 123451ca-8445-de46-9d55-352943316053
diff --git a/hyracks-net/src/main/java/edu/uci/ics/hyracks/net/protocols/muxdemux/MultiplexedConnection.java b/hyracks-net/src/main/java/edu/uci/ics/hyracks/net/protocols/muxdemux/MultiplexedConnection.java
index 8a21791..e124851 100644
--- a/hyracks-net/src/main/java/edu/uci/ics/hyracks/net/protocols/muxdemux/MultiplexedConnection.java
+++ b/hyracks-net/src/main/java/edu/uci/ics/hyracks/net/protocols/muxdemux/MultiplexedConnection.java
@@ -337,7 +337,7 @@
         }
         if (readerState.pendingReadSize > 0) {
             int newPendingReadSize = readerState.ccb.read(sc, readerState.pendingReadSize);
-            muxDemux.getPerformanceCounters().addPayloadBytesRead(newPendingReadSize - readerState.pendingReadSize);
+            muxDemux.getPerformanceCounters().addPayloadBytesRead(readerState.pendingReadSize - newPendingReadSize);
             readerState.pendingReadSize = newPendingReadSize;
             if (readerState.pendingReadSize > 0) {
                 return;