Running multiple threads on multiple CPU cores?

Can someone tell me if there is a way to run java code (with multiple threads) on multiple processors. Like an option flag for JVM upon running the code?

I've got 30-100 threads and all of them are allocated to a single core and the main idea was to spread them around so the calculation would go faster, but everything i tried so far didn't work.

It would be great if JVM supported an option (flag option) for running such code, but every flag i tried didn't work...

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Originally Posted by Dosta

Can someone tell me if there is a way to run java code (with multiple threads) on multiple processors. Like an option flag for JVM upon running the code?

I've got 30-100 threads and all of them are allocated to a single core and the main idea was to spread them around so the calculation would go faster, but everything i tried so far didn't work.

It would be great if JVM supported an option (flag option) for running such code, but every flag i tried didn't work...

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That is not a job for the JVM; it is the OS that allocates a core for a thread, the JVM is just a program. If you're running this on an MS Windows machine you can try to set the 'affinity' for the JVM, i.e. tell the scheduler (task manager) what CPUs (cores) the JVM is allowed to use.

kind regards,

Jos

On which OS do you run your Java program? The most JVM use multiple core by default. It can't disable.

I think your problem is that all threads are block on one synchronized. The result is that only one thread can be run.