Climate Model on a Mac Project #6: Success!


After a long struggle trying to work with various compilers, today, I decided to try the Portland C/Fortran compilers. I’ve had success with them before. Fortunately for me, it worked! I actually got the model running at a low resolution! Tomorrow, I’ll try a high resolution.

As of tonight, I’ve only run a single year at the low resolution. I have 8 processors, and only 2 gigs of ram. It took about 20 minutes to run the single year. Translated out to a full wallclock day, that’s about 72 model years. I have to admit I’m a little disappointed in the speed. However, I am a little thin on the RAM, with only 2 gigabytes, which probably slows things down. CPU usage didn’t seem to peek over 50%, so more ram may translate to more speed.

Once I looked at some comparisons with other system, I was a little happier. Take a look at this figure modified from that FOAM homepage:

Rodinia is my machine.

The 72 years-per-day speed, if it holds, compares very well with existing, high powered clusters. Of these systems, I’ve had some experience with JAZZ running a higher resolution model. Given that Rodinia’s performance is twice as fast as JAZZ, I feel the higher resolution models will perform quite well on this system. It’s also important to note that these other systems listed are not newer clusters, although many are still in operation. On the other hand, this system has a relatively low barrier of entry, it can double as a desktop mac when not in operation, and most importantly, no competition for cpu time.

I still have more configuration work to sort out. Getting the model to run via PBS on a user’s account is the priority.

More details soon!

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