help! multi-threading problem on hyperthreading smp linux server

[Garry Hodgson]

aahz at pythoncraft.com (Aahz) wrote:

> What version of Python?

2.2.2, on all machines but the windows one, which runs 2.3.

> What happens if you enable both CPUs without
> hyperthreading?  

same thing.  it fails on the one machine, works on the rest,
including another (older) dual processor machine running 
linux smp kernel.

> What happens if you only start ten threads (fifty
> threads isn't huge, but it's definitely large)?

same thing.  works fine for 1 thread :-).

> Have you applied all relevant OS patches and/or tried upgrading to a
> newer kernel?

it's looking like this may be the problem, since the machine it fails on
is running the oldest linux kernel of all of them.  all are 2.4.20's, but 
with different minor release numbers.

> Can you test the production system (or an equivalent) with
> Windows?  

nope.  we do have another machine that's identical hardware, 
though with slightly newer kernel patches.  we intend to test
on that tomorrow, during a maintenance window (that's a 
production machine).

> What happens if you run an equivalent test using C code?

C?  yuk!

----
Garry Hodgson, Technology Consultant, AT&T Labs

Be happy for this moment.
This moment is your life.