Java Performance Tuning

Client/Server Communications

To tune client/server or distributed applications , you need to identify all communications that occur during execution. The most important factors to look for are the number of transfers of incoming and outgoing data, and the amounts of data transferred. These elements affect performance the most. Generally, if the amount of data per transfer is less than about one kilobyte, the number of transfers is the factor that limits performance. If the amount of data being transferred is more than about a third of the network’s capacity, the amount of data is the factor limiting performance. Between these two endpoints, either the amount of data or the number of transfers can limit performance, although in general, the number of transfers is more likely to be the problem.

As an example, websurfing with a browser typically hits both problems at different times. A complex page with many parts presented from multiple sites can take longer to display completely than one simple page with 10 times more data. Many different sites are involved in displaying the complex page; each site needs to have its server name converted to an IP address, which can take many network transfers,^[14] and then each site needs to be connected to and downloaded from. The simple page needs only one name lookup and one connection, and this can make a huge difference. On the other hand, if the amount of data is large compared to the connection bandwidth (the speed of the Internet connection ...