This is old-ish advice. I tend to favor UseParallelOldGC even on Java 7, over G1GC, even though it may even be a default now?
The "Old" just means it also uses a parallel collector thread on the old generation. In general it's good to make use of increasingly multi-core machines by making GC multi-threaded. I don't know of any reason PermGen would be handled better or worse by it. Generally speaking the code I think you are using doesn't create much garbage anyhow. G1GC had some issues for me, but it may be weirdness specific to Apple's VM. You should use whatever you find to be best if you know what you're doing and have tested. On Tue, Jul 2, 2013 at 10:46 AM, Aleksei Udatšnõi <[email protected]> wrote: > JVM tuning section of "Mahout in Action" book recommends to use the > following GC instead of the default one: > > -XX:+UseParallelGC -XX:+UseParallelOldGC. > > Has anyone tries running servlets based on Mahout with UseConcMarkSweepGC > instead? > > Latter garbage collector is known for handling PermGen in Tomcat better > (especially during undeployment), but I am not yet sure how it will affect > the performance of Mahout servlets. > > The servlets produce user- and item-based recommendations, so its memory > usage and garbage collection should be as optimal as possible. > > Thank you, > Aleksei
