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JVM's suport for multicore processors and multiple processor systems

843829Sep 10 2008 — edited Nov 28 2008
Hi all,
Do you have any concrete information about Sun Hot JVM 1.5's support for multi-core processors and also its support for multi processor systems. I ask this because i am looking at deploying a multi threaded application written in Java 5 and want to know the best CPU arrangement for optimal performance.

Does JVM run itself on multiple CPUs?
Does JVM run native threads on multiple CPUs ? at the same time.
Is there a place where i can find out the exact behavior of the JVM in sus environments ?

Thanks.

Comments

843829
Hi,

Sun's JVM runs very well on multi-thread/core/chip systems and provides several mechanisms to scale well in such environments (for example Thread Local Allocation Buffers (TLABs), parallel gargabe collection threads etc.). Java threads are 1:1 mapped to operating system threads. There are lots of options that allow you to configure the JVM wrt number of gc threads and so on, although the defaults should in most cases work well. There is a lot information available at http://java.sun.com/docs/performance/index.html and some (quite outdated) information about threading at http://java.sun.com/docs/hotspot/threads/threads.html.

Nick.
843829
Hi nicolasmichael,
Thanks for the prompt reply,
From your post i understand that JVM's should support threading on multi core and multi CPU systems. However there is still one unknown in my equation.
Does Sun JVM support Native threads on Windows ? and Solaris ?
This is important because if Sun JVM does not support Native Threads then Green threads can only run on one CPU and using a multi core/processor system is a waste.

Also I know that IBM's VM has support for Native threads on Linux.

Thanks.
rishabh2u wrote:
Does Sun JVM support Native threads on Windows ? and Solaris ?
This is important because if Sun JVM does not support Native Threads then Green threads can only run on one CPU and using a multi core/processor system is a waste.
The Sun VM no longer has green threads. Last Sun VM that had those I believe was 1.2.

Green threads only existed on Solaris.
843829
So basically you are saying that Sun VM has ONLY NATIVE THREADS for ALL the operating systems ?
Thanks.
843829
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Locked on Dec 25 2008
Added on Sep 10 2008
#java-virtual-machine-jvm
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