Daniel Stux wrote:
> Here is what I see with Linux. I am running on a freshly installed
> RedHat 6.1 machine. With either JDK, running in native threads is
> absolutely crippling. There seems to be a serparate JDK process ID
> for each running thread, or otherwise something is casuing it to
> fork 15 times. Of these threads four or five of them just hammer the
> CPU, leaving the whole machine at a crawl. Actual performance of our
> Java GUI isn't too bad, but it's no where near where it should be.
You are seeing an artifact of the Linux threading model: native Java
threads are mapped onto kernel threads and kernel threads look a lot
(to ps and friends) like separately forked processes. As for your
four or five CPU hammers; that may be a Java problem, a Linux problem,
or a Java/Linux problem but it is hard to say without more details
from you.
For a *really* good analysis (IMHO) of Java / Linux threading issues,
kernel tweaks that can improve the situation, and what we might be
seeing in the 2.4 kernels unless the Linux kernel powers that be
address the situation, see the recently published paper:
Java, threads, and scheduling in Linux
Patching the kernel scheduler for better Java performance
at http://www-4.ibm.com/software/developer/library/java2/index.html
Recommended reading; the Java on Linux situation really needs this
kind of work. (Speaking only for myself.)
--
Jonathan Doughty The MITRE Corporation [EMAIL PROTECTED]
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