I run a java program i called it craft.jar the ram it uses is good but it times its cup usage will spike and ill have issues, i have ubunto 10 opendjdk6 64 bit everything and 6 2.00Ghz Xeon cores. the ave load on all cores is 2% but when i get heavey with my java program use only to on the cores will jump to 90-100% usage and the outheres will stay at 2%.
Qusetion is how do i force the program to run on 5 of the 6 cores to lessen issues with spiking? i use this to start my java program

umm bumbing......

To use multiple cores, the Java program should be multi-threaded in itself; you can't spread the load if it's just running a sequence of instructions one after the other.

Assuming you can't reprogram the code to use a more parallel algorithm, one thing you can do is change how the garbage collector works, so at least Java's garbage collector is using a different CPU to the main program. You could try using this:

or this:

instead of -Xincgc.

I couldn't find the page describing all the GC options, but there are a list of the major ones at http://openjdk.java.net/groups/quali...gurations.html (see the bottom of the page).

This may also be of interest: http://java.sun.com/docs/hotspot/gc1.4.2/faq.html

Hope that helps,

—Robert J Lee

1 members found this post helpful.

so i under stand that -XX:+UseParallelGC will make the programs garbage collector use a diffrent core form the main program? is that right?
is there a way i can sneek -Xshare:auto in there?

woodzy,

Bumping is against policy, useless, & clutters the thread. -- Please stop doing that.

While it isn't against the rules, quoting the entire preceding post is usually unnecessary, also clutters the thread, & may may be counterproductive because it hides your reply. -- That may be why you felt the need to bump. Now that I have removed it (the quotation), maybe the increased visibility will help get you an answer.

i am very sorry for that i was un aware of that policy

You did it again, I wonder if you are aware of the 2 "Post Reply" buttons in each thread? Both are on the left side & not in any post. The top one is just above the 1st post, & the bottom one is just below the last post. There also is a "Quick Reply" area only a little further down. Please use one of those unless replying with a quotation is really necessary.