Data Type

Integer

Default Value

0

Description

This parameter controls how data is divided to stream to/from the GPU in parallel with processing. If you change the default value you should consider the following:

  • Low value of ICHUNK:
    • (-) Smaller transfer to/from the GPUs,
    • (-) Less reuse of data on the GPUs,
    • (-) Less work performed with each kernel execution,
    • (+) Quicker startup and shutdown.
  • High value of ICHUNK:
    • (+) Larger transfers to/from the GPUs,
    • (+) Increased reuse of data on the GPUs,
    • (+) More work performed with each kernel execution,
    • (-) Longer startup and shutdown.

Values that are not an integer multiple of CUDA cores may result in decreased performance. The default value of 0 will cause FMS to select the optimum value for the type of data being processed (real or complex) and the properties of the GPUs.

This parameter also influences the selection of matrix block size. FMS will try to select blocks NEQBIO that are an integer multiple of ICHUNK * MAXGPU.