MATLAB freeze memory problem

Hi there, our lab has been trying to solve the following problem and I was hoping that someone might be able to help.

• MATLAB R2012b operating on Scientific Linux 6 is freezing when memory usage increases with different programs/code--i.e., you need to kill the PID. It was running a week ago and we have more than enough memory to handle the jobs (approx. 10G of RAM and 80G hard disk; also swap is fine, not that this matters). Jobs with lower memory requirements run fine and 'bench' works fine.

Would resetting or re-installing MATLAB be the only solutions? Could this be due to our license? (it's current but it is stored on another server)

Many thanks, Dominic

Answer 1

[Jan]

Find out, what you changed since it ran fluently. Compare the current code with your backups.

Even if the memory was fine before, a mistake like x=rand(1e6) can freeze the machine for hours.

Are there any infinite loops, e.g. in C-Mex functions?

A freezing Matlab is not an effect of problems with the license. If you have problems with the license, you get an error message, which tells you, that you have problems with the license. There are no magic connection to the processing speed or even a freezing of Matlab.

[Dominic Dwyer]

Hi Jan, thanks very much for your quick response and suggestions.

To our knowledge, we haven't changed anything on the server. The functions it's running haven't been changed, but to make sure I checked it with a completely different, stable, publicly-available, toolbox with similar memory demands (voxel-based morphometry) and it hangs just the same.

Today I also reset everything using instructions from one of your previous posts, but this didn't work. I'm stress testing the server using another program, but so far it's not freezing with other programs.

I'm going to try a reinstall, but it's frustrating that I can't find the problem!

[Walter Roberson]

Checks to see if the license is still active can cause freezing if the remote system does not respond promptly. In such a case the CPU utilization should go to pretty much 0.

[Dominic Dwyer]

That's interesting, because we were having problems with the license file previously--matlab slow to load and slow to initialise analyses. We (thought) that we'd fixed that problem though because it's not occurring any more.

This is a complete freeze only during high demand jobs; e.g., we're not getting any freezing during jobs with low processing demands (i.e., low CPU, memory, io, disk write), which made me think previously that it couldn't be the same problem. The CPUs do go to zero though.

Any other thoughts would be much appreciated.

Answer 2

[Anton]

Dominic, did you manage to track the problem? I have exactly the same issue with Matlab. Tried multiple versions of Matlab and gcc. One machine with Scientific Linux 6.5 freezes randomly, others work flawlessly. So far I managed to producer the same behaviour with a simple script (operations with 3D matrices). I'll report as soon as I reproduce it with a VERY simple script.