Data Type

Integer

Default Values

ICHUNK = 192
ITRCHK = 192
ITMCHK = 192.

Description

These parameters control how data is divided to stream to/from the GPU in parallel with processing. The computation influenced by these values are

FMS Parameter
Parameter Type of Computation
ICHUNK Matrix Multiply
ITRCHK Triangle Solve
ITMCHK Triangle Multiply
Symmetric Only

If you change the default value you should consider the following:

  • Low values:
    • (-) 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 values:
    • (+) 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.

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.