MAX JVM on AMD Opteron / Linux system in 32bit mode

[Dan]

Hi everyone - Thanks in advance for your replies.

I currently support a system that is Redhat 8.0/JDK 1.4.2/Xeon
motherboard with 9GB of RAM. The max JVM size I can get is about
1700MB or 1.7GB. I understand why this is from digesting numerous
posts on the subject.

My question is this. If I had an AMD Opteron system, running Redhat
8.0 compiled for the AMD Opteron, would I be able to allocate a larger
JVM if java was running in 32 bit mode (this is a hard requirement due
to JNI based 3rd party software).

My experience with Solaris/Sparc would seem to say the answer is yes -
But I have not tested this. On Solaris I can get at least a 3GB JVM
fired up using the following as a quick test "java -d32 -Xmx3072M
-showversion".

Does anyone have any experience with this or the configuration (AMD
Opteron, at least 4GB of RAM, Linux, JDK 1.4.2) to do a quick test?

Dan

 

[Roedy Green]

My question is this. If I had an AMD Opteron system, running Redhat
8.0 compiled for the AMD Opteron, would I be able to allocate a larger
JVM if java was running in 32 bit mode (this is a hard requirement due
to JNI based 3rd party software).

you mean 64 bit mode. I know sun has announced a 64-bit JVM for the
Opteron, but I have not the money for the hardware to try it out.

I see 64 bit "ia" in the list of JDK downloads. Does that mean install
anywhere? Itanium, Opteron? see http://mindprod.com/jgloss/jdk.html

I would try googling newsgroups to see what sort of complaints are
coming up.

see http://mindprod.com/jgloss/itanium.html
http://mindprod.com/jgloss/opteron.html

 

[Dan]

Thanks for you reply.

Let me clarify what I mean.

The JVM on the 64 bit Opteron would be running in 32 bit mode. I
think, not having tried it, that you could use either a JVM built for
64 bits or 32 bits. If it was a 64 bit JVM, I would be running with
the "-d32" command line option when I invoke the java command line.