6 Replies Latest reply on Jun 4, 2013 11:06 AM by zhouyaguo

    Should we use UseParallelOldGC instead of UseParallelGC in hornetq user manual?

    zhouyaguo
    zhouyaguo Jun 3, 2013 11:47 AM

      Hi:

        JVM argument -XX:+UseParallelGC is recommended to be set in hornetq user manual ( https://github.com/hornetq/hornetq/blob/master/docs/user-manual/en/perf-tuning.xml#L238 ). I think we should use UseParallelOldGC instead of UseParallelGC.

        we can find the jvm arguments on oracle website http://www.oracle.com/technetwork/java/javase/tech/vmoptions-jsp-140102.html , it says:

       

        XX:-UseParallelGC = Use parallel garbage collection for scavenges. (Introduced in 1.4.1).

        -XX:-UseParallelOldGC = Use parallel garbage collection for the full collections. Enabling this option automatically sets -XX:+UseParallelGC. (Introduced in 5.0 update 6.)

        where Scavenges = Young generation GC.

       

        UseParallelGC would result in parallel young + serial old  and UseParallelOldGC in parrallel young + parralel old gcs.

       

        I made a pull request: https://github.com/hornetq/hornetq/pull/1105

       

        Any ideas?

       

      links:

      http://www.oracle.com/technetwork/java/javase/tech/vmoptions-jsp-140102.html

      http://mail.openjdk.java.net/pipermail/hotspot-gc-use/2008-December/000300.html

      http://stackoverflow.com/questions/6236726/whats-the-difference-between-parallelgc-and-paralleloldgc