MultiCPU 494

Been there, done that.

Debugging multi-threaded code is no simple task. A very talented guy I used to work with run his MT code on a dual processor Linux box with no hbuttle. He then tried it on a quad processor Sun SPARCstation 20 and found it crashed. He found it was a real bug, that just never seemed to occur on single processor Suns or a dual processor Linux box.

I wrote a program that would work fine on numerous UNIX boxes *all* are multi-processor. These include PCs running Linux, *BSD etc, Suns, HPs running both HP-UX, Cray and others. It also run on single processor Dec Alpha. But it would not run properly on a Sun running Linux. I tended to ignore that and blame Linux on SPARC, as multi-threaded Linux on SPARC is not well tested.

But then I found it sometimes mis-behaved on a quad processor IBM RS-60000. Then I became suspicious of my code, as I trusted AIX somewhat better than Linux on a SPARC.

Sure enough, I found a bug in my code.

There is a open-source library that you can link in that is supposed to help find such bugs. I can't say I was over-impressed with it, but it might be worth a try.

Multi-threaded code is just hard to write properly. Finding bugs is hard.

BTW, I have a couple of book recomdations.

1) This is one *NOT* to buy. It is the second worst technical book I have ever seen. I am afraid to say it is published by Sun.

"Mulbreasthreaded programming with pthreads"

by B. Lewis and Daniel J Berg, published by Sun Microsystems.

IMHO a total waste of time. It tries to cover far too much, including threads on OS2, yet ignores LWP on Solaris. Seems odd for a book published by Sun.

2) "Foundations of mulbreasthraaded, parallel and distributed programming"

by Gregory R. Andrews, Addisonm Wesley. Excellent book.

I'm not sure if the author is the same 'Greg Andrews' that used to post to the Sun related newsgroups, but I suspect not. But that is well worth the money. Just forget the Sun book.

-- Dave K

Minefield Consultant and Solitaire Expert (MCSE).

Please note my email address changes periodically to avoid spam. for a couple of months only. Later set it manually.