[ltp] help --size of my program too large

[Harry Mangalam]

I'm not a fortran user, but it sounds like by 'model' you mean that you're 
allocating static arrays that exceed the size of available memory?

If so, and the you think you have physical memory larger than what gets reported 
by size (what does 'cat /proc/meminfo' tell you?), you may be running a kernel 
that is not set up to allow large (>900MB) memory by default - most distro linux 
kernels only support the 900MB limit - you may have to explicitly choose one 
that supports the 4GB (or 64GB) limit or compile it yourself.

what kernel version & distro are you using?  Did you build it yourself?

There are also memory issues having to do with what the kernel reserves for 
itself when memory gets tight, and you might be gettign close, depending on what 
other apps or window managers, etc you're running.

my 2 cents.

h

George Jiang wrote:
> Hi ,  sorry to put this message here. But I know there are a lot of 
> experts on Linux here, and I don't know other pertinent linux 
> newsletters. Thanks.
> 
> --- Steps ---
> During my research I have to use a Fortran program for scientific 
> computation.
> It deals with a large model.
> first, I use "f77 aa.f -o aa.exe" to compile it;
> second, I use "size aa.exe" to view the size of the exe file;
> third, I use "./aa.exe" to run the program.
> 
> --- Problem ---
> When the size is larger than 1.0 G, I got the message "Segmentation 
> fault (cor
> e dumped)"  when I run "./aa.exe";
> Then I adjusted the model size, and redo step1,2,3. This time the 
> program runs
> well.
> 
> --- Question ---
> My computer has 1.5G memory; does anyone know how to fix this problem so 
> that I can run the program with a larger model (my research requires me 
> to run a large model)?  such a
> s modify the configuration or settings of the Linux system... ( red hat 
> linux 8.0
> )?
> ( I've thought about MPI; But it's not easy to modify the program for 
> parralel
> computing, so I want to find another solution)
> 
> Thanks a lot!!
>   George Jiang
> 
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-- 
Cheers, Harry
Harry J Mangalam - 949 856 2847 (v&f) - hjm@tacgi.com
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