I have a workstation with dual xeon processor with 64 GB RAM. I have installed COMSOL Multiphysics as per the Installation Guide. But when I checked the CPU usage, I found that only one of the processors is utilized per simulation. The other one is unutilized. When I run the second application, it uses the other processor. So when we run 2 or many COMSOL Simulations - Its ok that the CPU is utilized properly. As my simulation is a bit heavier, I need to use both the processors simultaneously for a single application. What settings should be made to do this?
In Preferences, go to multicore and cluster computing option, Tick the number of processors option.(Version Comsol 4.4)
By default if will show the maximum number processors you have, you can limit them by entering the number of processors you would like to utilize.
Dear Shivaprasad - As you have said, it is by default showing the max no of cores (2*8 cores = 16). But it is utilizing the half of it i.e. 1 processor
Dear Hakeem,
Many of Comsol's numerical methods do not scale well when running in parallel on different cores. I think they programmed it nicely with different threads, but when all threads are working on the same matrix, they all end up waiting for each other. In that case, 8 cores are no faster than 1. Of course, you can still run two simulations at the same time.
Thorwald van Vuure
Research Scholar Mr. Nyas,
Regardless of simulation, parallelism needs to be thought in either of three ways: 1. Data parallelism, 2. Task parallelism, and 3. Mixed (Data and Task) parallelism. If your simulation requires large amount of data to be processed, you can divide the data, run the simulation and then combine results later. For task parallelism, steps in finite element method are divided and run on different machines. The result from previous finite element step is fed into the next step running on different machine/processor. Mixed parallelism requires one to think both the options together.
If you think about your simulation in this way, you could understand the nitty-gritty of COMSOL. As always it is a good idea to write your own code (scholarly advice :)
Best !
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