Excessive memory usage

[Hannes Wallnoefer]

Hi Michel,

Thanks for the quick and easy github repository to reproduce this.

Looking at the code running with jvisualvm I can't see any excessive 
memory usage. Both with JDK 8u60 and 9 heap usage is around 150 MB.

The fact that Java reserves a lot of memory on Linux is a well-known 
fact. It's not related to Nashorn, but rather to how Java interacts with 
the Linux memory system. It is a bit annoying, but usually it's not a 
problem and does not reflect Java heap usage.

Hannes


Am 2015-10-05 um 20:02 schrieb Michel Krämer:
> Hi!
>
> I'm currently working on TypeScript support for Vert.x. I'm trying to 
> run the TypeScript compiler on Nashorn. It works well, but the process 
> uses a lot of memory. I'm wondering if there is a bug in Nashorn or if 
> I'm doing something wrong.
>
> I uploaded a small example project demonstrating the issue:
> https://github.com/michel-kraemer/nashorn-memory-test
>
> I tested it under Ubuntu 14.04 with JDK 8u60. I run
>
> javac Main.java && java -Xmx256M -cp . Main
>
> and watch the process with top. The resident memory quickly goes up to 
> 1 GB and after about 20 iterations grows even further to 1.2 GB. After 
> about 500 iterations it sometimes even goes up to 1.5 GB where it 
> stays until the end of the program. That's 1.3 GB more than I 
> specified with -Xmx. I know this is metaspace, but I wonder why 
> Nashorn needs so much of it. By the way, even if I do only 1 iteration 
> the process still goes up to 400-500 MB.
>
> Any ideas?
>
> Cheers,
> Michel