The overhead of calling an

Intel® oneAPI Math Kernel Library

function for small problem sizes can be significant when the functionhas a large number of parameters or internally checks parameter errors. To reduce the performance overhead for these small size problems, the

Intel® oneAPI Math Kernel Library

direct call

feature works in conjunction with the compiler to preprocess the calling parameters to supported

Intel® oneAPI Math Kernel Library

functions and directly call or inline special optimized small-matrix kernels that bypass error checking.For a list of functions supporting direct call, see Limitations of the Direct Call.

To activate the feature, do the following:

Intel® oneAPI Math Kernel Library

skips error checking and intermediate function calls if the problem size is small enough (for example: a call to a function that supports direct call, such as

dgemm

, with matrix ranks smaller than 50).