[mesa-users] Fwd: gfortan multithreading problems with mesa

[Bill P. <pa...@ki...>]

Hello again,

Have you tried the experiment of running 2 gfortran versions of star simultaneously with multithreads?
Did you see the problem that I see on my mac?   If so, please try this fix.

The gfortran multithreading problem goes away (at least on my machine) if I use this file:


put it in mesa/mtx/private
then
cd mtx/test
./mk
./ck
./export

Then
	cd /star/test
	./mk
	./ck
	./export

Then
	remake your applications that use star

Then try running 2 instances of star in different terminals simultaneously with multithreads.

In the previous version of the file, we were trying some different OpenMP directives in hope
of getting better performance.  Didn't make any difference for performance, but it did
apparently trigger a problem in the gfortran runtime support for OpenMP -- at least that's
what it looks like currently.

--Bill








Begin forwarded message:

> From: Bill Paxton <pa...@ki...>
> Date: September 22, 2011 7:42:03 AM PDT
> To: Mesa users <mes...@li...>
> Subject: [mesa-users] gfortan multithreading problems with mesa
> 
> Hi,
> 
> I've just noticed something suggesting a multithreading issue with mesa when compiled with gfortran.
> It is undoubtedly a bug on my part, but I haven't tracked it down yet.   It might be behind some 
> ot the installation problems we've been having.
> 
> Basically, when compiled with gfortran (but not with ifort) I can quickly cause a convergence failure in a mesa star 
> at any time during a run simply by starting up another run simultaneously in another terminal.   However, if I change
> to a single thread, they don't interact and don't run into trouble.
> 
> I'll look into this, but in the meantime, you might try setting OMP_NUM_THREADS to 1 and see if the install goes better.
> 
> -Bill
> 
> 
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