How's linux-ibm-jdk14 in the memory footprint department?

[Nicolas Gieczewski]

Thanks for the suggestion. I could only get it down to about 152 MB with an initial heap size of 8 MB and a maximum size of 16 MB. I believe this is probably too small, though (actually, I have no idea, guess I'll have to see how often the GC is kicking in). Even though not all of the 152 MB (or 203 MB, for that matter) are in main memory at any given time, don't they become unavailable to the OS, anyway?

Nevertheless, it's still pretty much of a memory hog even with such a tiny heap. On Windows, its total memory footprint is around 23 MB as I had said, with only about half of that in main memory at any given time. Do you know how I can check the default heap size of the JVM? I'd like to compare default heap sizes on *nix and Windows and see what the JVM's memory footprint is on each platform without counting the heap.

Thanks again!

Nick


----- Original Message ----- 
From: "Sparrevohn, Thomas" <thomas.sparrevohn at eds.com>
To: "'Nicolas Gieczewski'" <foo at bar.org>; <freebsd-java at freebsd.org>
Sent: Wednesday, December 10, 2003 22:07
Subject: RE: How's linux-ibm-jdk14 in the memory footprint department?


Allow me to take a look at it tomorrow. The RSS I have seen I was about 40MB or so and there no doubt that it will present a problem on a 64MB host - It seems to start with a quite high default heap - around 128MB - But I need to verify it. Have you tried to limit the Heap? It is quite normal for Heaps to like "huge" areas of memory but it does not mean that it is needed.

-- Thomas


-----Original Message-----
From: owner-freebsd-java at freebsd.org [mailto:owner-freebsd-java at freebsd.org] On Behalf Of Nicolas Gieczewski
Sent: 10 December 2003 19:08
To: freebsd-java at freebsd.org
Subject: Re: How's linux-ibm-jdk14 in the memory footprint department?


Well, naturally the 203 MB cannot be in physical memory all at the same time on a box with 64 MB of RAM, but the JVM's total memory footprint (text + code + data) is 203 MB, and I can feel it in the constant disk paging taking place while it's running.

I'm still hoping someone using IBM's JVM will eventually get back to me and tell me its memory footprint is around the same, so that I won't get an urge to reboot for USER_LDT to take effect in order to be able to use linux-ibm-jdk14 instead :-)

Cheers,
Nick


----- Original Message ----- 
From: "Sparrevohn, Thomas" <thomas.sparrevohn at eds.com>
To: "'Nicolas Gieczewski'" <foo at bar.org>; <freebsd-java at freebsd.org>
Sent: Wednesday, December 10, 2003 10:49
Subject: RE: How's linux-ibm-jdk14 in the memory footprint department?


The real memory usage is much smaller - I would think that it is because it allocated the memory range but never actually uses it. 


-----Original Message-----
From: owner-freebsd-java at freebsd.org [mailto:owner-freebsd-java at freebsd.org] On Behalf Of Nicolas Gieczewski
Sent: 09 December 2003 18:13
To: freebsd-java at freebsd.org
Subject: Re: How's linux-ibm-jdk14 in the memory footprint department?


Hello Gabriel,

Thank you for your response. I doubt it's the GC, for memory usage jumps to those values right after the VM starts, i.e. when there's not much to garbage collect yet. Also, it says around those figures for the rest of the program's lifetime. This is a console application, by the way.

What I'd like to know is whether IBM's implementation of the JVM happens to use a little less memory. I think 203 MB is too much for a console application, and that box only has 64 MB of RAM. I did install linux-ibm-jdk14 to check this myself, but found out it requires the USER_LDT setting in the kernel, and I can't reboot because of a stupid setting since I'm running important services on the box.

Any linux-ibm-jdk14 fans out there?

Thanks,
Nick


----- Original Message ----- 
From: "Gabriel Ambuehl" <gabriel_ambuehl at buz.ch>
Cc: <freebsd-java at freebsd.org>
Sent: Tuesday, December 09, 2003 13:01
Subject: Re: How's linux-ibm-jdk14 in the memory footprint department?


Hello Nicolas,

Tuesday, December 9, 2003, 3:57:10 PM, you wrote:

> Hello,

> Sun's VM eats up ~203 MB of memory to run a small program on my
> FreeBSD box, whereas on Windows it only uses ~23 MB. Besides not 
> understanding how the difference can be so big, I wonder if anyone has 
> tried linux-ibm-jdk14? Is it a memory hog like Sun's?

Are you sure this isn't just some Garbage collector behaving differently?

Best regards,
 Gabriel