Multicore Settings

COMSOL supports two modes of parallel operation: shared-memory parallel operations and distributed-memory parallel operations, including cluster support for Windows and Linux. This section covers shared-memory processing, or multithreading, which is important for the performance of COMSOL computations. Some terms that are frequently used in when describing multithreading are:

•	Core: The core is a processor core used in shared-memory parallelism by a computational node with multiple processors.

•	Speedup is how many times faster a job runs on N cores compared to 1 core, on a specific compute node. The speedup depends on the simulation type, the hardware used, and hardware drivers used.

On OS X, the default number of processor cores used by COMSOL is the total number of available physical cores. For example, if you have a 2 x dual core machine, 4 cores are used in parallel by a COMSOL process.

shared-memory options

From the terminal window, use the comsol command option -np to control the number of cores and processors used. The default is to use all available cores and processors. For example:

comsol -np 2

launches COMSOL using 2 cores (if available).

You can experiment to find the options that work best for your configuration. For more information see the COMSOL Multiphysics Reference Manual.