Name: jl125535 Date: 09/02/2004


FULL PRODUCT VERSION :
java version "1.5.0-beta2"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0-beta2-b51)
Java HotSpot(TM) Client VM (build 1.5.0-beta2-b51, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Linux manu-home.homelinux.net 2.6.8-1.521 #1 Mon Aug 16 09:01:18 EDT 2004 i686 athlon i386 GNU/Linux

A DESCRIPTION OF THE PROBLEM :
Calling Thread.setPriority() doesn't work on Linux. From monitoring the system calls,
(using strace) we see the following system call being made by the JVM when Thread.setPriority() is called.

sched_setscheduler(ThreadID, SCHED_OTHER, { priority }) = -1 EINVAL (Invalid argument)

This system call fails, because for the scheduling policy, SCHED_OTHER, the only priority valid is 0. The priorities should be set using the setpriority() and getpriority() system calls on Linux.


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Any program which calls Thread.setPriority()

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The native thread's priority should be changed.
ACTUAL -
system call fails.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
public static void main(String[] args) {
 Thread.currentThread().setPriority(Thread.MIN_PRIORITY);
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Can use JNI to make the right system call.
(Incident Review ID: 301514)
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