Suggestions for making writing faster? DFSClient waiting while writing chunk

[stack]

Writing a file, our application spends a load of time here:

        at java.lang.Object.wait(Native Method)
        at java.lang.Object.wait(Object.java:485)
        at
org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.writeChunk(DFSClient.java:2964)
        - locked <0x00007f11054c2b68> (a java.util.LinkedList)
        - locked <0x00007f11054c24c0> (a
org.apache.hadoop.hdfs.DFSClient$DFSOutputStream)
        at
org.apache.hadoop.fs.FSOutputSummer.writeChecksumChunk(FSOutputSummer.java:150)
        at
org.apache.hadoop.fs.FSOutputSummer.flushBuffer(FSOutputSummer.java:132)
        - locked <0x00007f11054c24c0> (a
org.apache.hadoop.hdfs.DFSClient$DFSOutputStream)
        at
org.apache.hadoop.fs.FSOutputSummer.flushBuffer(FSOutputSummer.java:121)
        - locked <0x00007f11054c24c0> (a
org.apache.hadoop.hdfs.DFSClient$DFSOutputStream)
        at
org.apache.hadoop.fs.FSOutputSummer.write1(FSOutputSummer.java:112)
        at org.apache.hadoop.fs.FSOutputSummer.write(FSOutputSummer.java:86)
        - locked <0x00007f11054c24c0> (a
org.apache.hadoop.hdfs.DFSClient$DFSOutputStream)
        at
org.apache.hadoop.fs.FSDataOutputStream$PositionCache.write(FSDataOutputStream.java:49)
        at java.io.DataOutputStream.write(DataOutputStream.java:90)
        - locked <0x00007f1105694f28> (a
org.apache.hadoop.fs.FSDataOutputStream)
        at
org.apache.hadoop.io.SequenceFile$Writer.append(SequenceFile.java:1020)
        - locked <0x00007f1105694e98> (a
org.apache.hadoop.io.SequenceFile$Writer)
        at
org.apache.hadoop.io.SequenceFile$Writer.append(SequenceFile.java:984)

Here is the code from around line 2964 in writeChunk.

        // If queue is full, then wait till we can create  enough
space
        while (!closed && dataQueue.size() + ackQueue.size()  > maxPackets)
{
          try
{

dataQueue.wait();
          } catch (InterruptedException  e) {

}

        }

The queue of packets is full and we're waiting for it to be cleared.

Any suggestions for how I might get the DataStreamer to act more promptly
clearing the package queue?

This is hadoop 0.20 branch.  Its a small cluster but relatively lightly
loaded (so says ganglia).

Thanks,
St.Ack