threads branch on darwin/ppc: one file now passes but two others hang

[James E Keenan]

I have some good news and some bad news about the state of the threads 
branch on Darwin/PPC.

Seeing today that there had been additional commits to this branch in 
the past few days, I tested it today for the first time since commit 
e567a21 on July 25.  I got a completely successful 'make test' at commit 
56c96dde25.  But since there's also been a lot of activity on master in 
the past few days, I wondered (a) does master PASS 'make test' (it 
does); and (b) what will happen when the threads branch is merged into 
master?

So I created a local, intermediate branch called 'formerge' by merging 
threads into master.  Unfortunately, I started to get intermittent 
failures in several files which come up later in 'make test' than 
't/pmc/nci.t' (the file where we have been experienced hanging on 
several tests):

t/pmc/timer.t: hung once during make smolder_test, passed next time and 
when run individually.

t/src/threads.t: hung during make smolder_test, then passed individually 
and during 'make src_tests'.

This was suspicious.  So I again retested master -- which PASSed again 
and then retested the threads branch -- which hung at 
t/pir/timer_exit.t.  When I ran 'prove t/pir/timer_exit.t' individually 
while 'make test' was still hanging at its invocation of that test, it 
hung.  Then, after I killed 'make test', I tried 'prove 
t/pir/timer_exit.t' -- which ran quickly and PASSed.

Now, I wasn't logging the first runs I did today, so there's a 
possibility that I misremember the name of the first failing test file, 
i.e., that it might have been t/pir/timer_exit.t rather than 
t/pmc/timer.t that failed the first time around.

Even granting that, I know that I have experienced intermittent hangs in 
at least two files -- t/src/threads.t and t/pir/timer_exit.t -- either 
in the threads branch per se or in a branch where I've merged threads 
into master.

But the good news remains: On this platform, t/pmc/nci.t is now PASSing 
repeatedly and, I hope, consistently.

Thanks to everyone who is following these issues.  It would be good to 
see if we're experiencing similar results on other non-Linux or 
non-Intel systems.

Jim Keenan