At least once a day, we are seeing Jenkins slow to an absolute crawl, where requests take ~5 minutes to load a page. CPU load is usually fine (~1 or less) and there doesn't seem to be anything on the machine. However, the logs from Jenkins are hundreds of the following, over and over again:

[Winstone 2011/08/26 14:07:52] - Error within request handler thread
java.io.EOFException
at java.io.DataInputStream.readFully(DataInputStream.java:197)
at java.io.DataInputStream.readFully(DataInputStream.java:169)
at winstone.ajp13.Ajp13IncomingPacket.<init>(Ajp13IncomingPacket.java:60)
at winstone.ajp13.Ajp13Listener.allocateRequestResponse(Ajp13Listener.java:173)
at winstone.RequestHandlerThread.run(RequestHandlerThread.java:79)
at java.lang.Thread.run(Thread.java:636)

I have attached two thread dumps (about 10-15 minutes apart).