GC algorithms

[luke]

Thanks Bernd, Ryan

I'm working on webApp hosted on Jboss AS (java6), that invoke an heavy
batch job.
So I'm mainly interested in throughput.
Application is working on multi cpu servers and when my application is
running, I've only few GB of phisical memory available (3-4 GB).

We started with -Xms1g -Xmx3g and performance was very bad.
So we passed to -Xms6g -Xmx6g and we set Parallel algorithm for young and
old generations.
Using these jvm triggers application works quite well with current data.
Maybe in future I've to try other improvment in order to deal with data
greater than now.

I'll try with low pause GC and G1 to compare performance with parallel
algorihm.
Thanks for your suggestions,
luca
2013/3/17 Bernd Eckenfels <bernd.eckenfels at googlemail.com>

> Hello,
>
> Am 17.03.2013 um 12:54 schrieb luke <luke.bike at gmail.com>:
>
> > I have to improve performance on an application running on
>
> You first need to specify what performance improvements mean (more
> throughput, less overhead, shorter or more consisten Pause times) then you
> can better chose a GC strategy.
>
> You also should device a test benchmark where you can measure if your new
> goals are meet.
>
> You also need to consider different aspects and phases of your application
> life cycle - do they all put the same pressure on the memory?
>
> And finally a Verbose GC log file would help to analyze your system. But
> with 97% throughout, there is a bit to improve, but certainly not a large
> breakthrough.
>
> How many Logical CPUs does your Server have, how many RAM, what is the
> memory footprint of the app - those are typical questions which help you
> with the decision.
>
> I think there is typically only the parallel GC, the low pause GC and G1.
> You can try all 3. But if you not care about pause times you might have
> chosen the best setting already.
>
> Bernd
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