Administration guide > Tune and performance > Use WebSphere Real Time

WebSphere Real Time in a stand-alone environment

Use WebSphere Real Time with WebSphere eXtreme Scale. By enabling WebSphere Real Time, you can get more predictable garbage collection along with a stable, consistent response time and throughput of transactions in a stand-alone eXtreme Scale environment.

Advantages of WebSphere Real Time

WebSphere eXtreme Scale creates many temporary objects that are associated with each transaction. These temporary objects deal with requests, responses, log sequences, and sessions. Without WebSphere Real Time, transaction response time can go up to hundreds of milliseconds. However, using WebSphere Real Time with WebSphere eXtreme Scale can increase the efficiency of garbage collection and reduce response time to 10% of the stand-alone configuration response time.

Enable WebSphere Real Time

Install WebSphere Real Time and stand-alone WebSphere eXtreme Scale onto the computers on which you plan to run eXtreme Scale. Set the JAVA_HOME environment variable to point to a standard Java™ SE Runtime Environment (JRE).

Set the JAVA_HOME environment variable to point to the installed WebSphere Real Time. Then enable WebSphere Real Time as follows.

  1. Edit the stand-alone installation objectgridRoot/bin/ | .bat file by removing the comment from the following line.

    WXS_REAL_TIME_JAVA="-Xrealtime -Xgcpolicy:metronome -Xgc:targetUtilization=80"

  2. Save the file.

Now you have enabled WebSphere Real Time.

To disable WebSphere Real Time, you can add the comment back to the same line.

Best practices

WebSphere Real Time allows eXtreme Scale transactions to have a more predictable response time. Results show that the deviation of an eXtreme Scale transaction's response time improves significantly with WebSphere Real Time compared to standard Java with its default garbage collector. Enabling WebSphere Real Time with eXtreme Scale is optimal if the application's stability and response time are essential.

The best practices described in this section explain how to make WebSphere eXtreme Scale more efficient through tuning and code practices depending on the expected load.

Parent topic:

Use WebSphere Real Time

Related concepts

WebSphere Real Time in WAS