Multi processor and Perl eq Problems.

[Allan Brehm Clausen]

For some time our Perl programs have stopped responding with a
"Blocked on kernel CV" notice in the debug/profiler.
It seemed to happen at random, and at random places in the code.

"Blocked on User CV" will be the normal info if the program is in he
sleep() function, "Yielded CPU" when it is heavily crunching numbers
and "Blocked on Keyboard CV" when waiting for keyboard entry.
But "Blocked on Kernel CV" leaves me clueless.

Then we noticed that turning off Hyper-Threading (as you should
anyway) an multi processor support relieved the problem.

Strangely enough, even to processors with HyperThreading turned off,
would crash Perl.

We tried it with the new LIB6G update, but that did'nt help any.
It seems that some threads are not waking up (wild stab in the dark).

We are running Perl v5.8.4 (5.00.05) on NetWare 6.5 sp5.

Has anyone experienced similar problem? Or maybe someone with the same
problems could try and turn of HyperThreading/Multiprocessor?

BTW: By turning off Multi Processor, I mean just going into Remote
Manager/Processors and closing the extra processor down, solves the
problem.

[Dave Bank]

Post by Allan Brehm Clausen
Then we noticed that turning off Hyper-Threading (as you should
anyway) an multi processor support relieved the problem.
Strangely enough, even to processors with HyperThreading turned off,
would crash Perl.

Have you tried turning off HT support in the BIOS?

[Allan Brehm Clausen]

Post by Dave Bank
Have you tried turning off HT support in the BIOS?

Yes. It didn't help.

HT + 1 proc = bad.
HT + >1 proc = bad.
1 proc = OK.

Post by Dave Bank
1 proc = bad.

Hmm.. Maybe I should make a testprogram, and send in the usual TID
info's :-(

[Guenter]

Hi Allan,

Post by Allan Brehm Clausen

Post by Dave Bank
Have you tried turning off HT support in the BIOS?

Yes. It didn't help.
HT + 1 proc = bad.
HT + >1 proc = bad.
1 proc = OK.

Post by Dave Bank
1 proc = bad.

Hmm.. Maybe I should make a testprogram, and send in the usual TID
info's :-(

post a short sample which can produce an abend on MP, and I will make sure
that the right developer gets it...

greets, Guenter.

[Allan Brehm Clausen]

Post by Guenter
post a short sample which can produce an abend on MP, and I will make sure
that the right developer gets it...

Well... it is going to be a bit difficult, when it doesn't abend.
We'll try and do a short code example that will reproduce the error.
Something were the program reports back on intervals, so it will be
obvious when it doesn't respond anymore.

Regards
Allan