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From "Weldon Washburn" <weldon...@gmail.com>
Subject Re: [drlvm][threading] taking a closer look at Harmony-2803 (stress.Mix hangs on rhel4)
Date Fri, 05 Jan 2007 15:20:14 GMT

An update.  I think I can cause the bug(s) we are discussing in this email
chain to surface 100% of the time on 2 cpu rhel4.  Hacking stress.Mix such
that it only runs the "spawn" method seems to do it.   This hack always
fails on 2 cpu rhel4 and never fails on 1 cpu winxp.  It would be
interesting to try on 1 cpu rhel4 and 2 cpu winxp.  If anyone has this
combination, please try it.  This would tell us if the bug is sensitive to

When I run the below patch on RI, it completes successfully every time.
Curiously it looks like the RI kills the "occupy" thread.  It prints on the
console output, "occupy terminated by java.lang.OutOfMemoryError...".  But I
don't see occupy terminate when running drlvm.  I will run more tests.  This
may actually be compounding the problems we are seeing.

Naveen, Rana,
Can you try the below patch on your hardware to see if you can reproduce
what I describe above?  Does the output look the same as Harmony-2803?

Below is an svn diff that makes the hard failure happen on 2 cpu rhel4:

Index: Mix.java
--- Mix.java    (revision 491852)
+++ Mix.java    (working copy)
@@ -93,6 +93,8 @@

     static Random random = new Random(0);
     static String selectThreadType(int i) {
+               return "spawn";
+               /*
         switch (i % 9) {
             case 0: return "uncontended";
             case 1: return "contended";
@@ -105,6 +107,7 @@
             case 8: return "exceptions";
         return "nothing";
+               */

     static int thread_number = 60;

On 1/4/07, Naveen Neelakantam <neelakan@uiuc.edu> wrote:
> On Jan 4, 2007, at 4:28 PM, Weldon Washburn wrote:
> > I see it hang consistently when running automated mode (build
> > test).  I have
> > seen it hang once when running manually from a linux terminal
> > window.  It
> > actually printed out "PASSED" then hung.  This leads me to suspect
> > there
> > might be problems with how System.out.flush() is working when there
> > are
> > multiple threads running on SMP.  Are you running on an SMP box?
> > Can you
> > give me the exact command line you are using?  I would like to try
> > it on my
> > box.
> Ok, cool.  I was seeing the exact same behavior (i.e. the test prints
> PASSED and then hangs).  So it sounds like you are on the right
> track, to me anyway.
> But to answer your questions: I am running RHEL4 update 4 on a core2
> duo.  The command line I am using is "java -cp . stress.Mix" (with my
> path and JAVA_HOME set appropriately).
> Naveen

Weldon Washburn
Intel Enterprise Solutions Software Division

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