Developer Reference

  • 2021.1
  • 12/04/2020
  • Public Content


Frees unused memory allocated by the
Intel® oneAPI Math Kernel Library
Memory Allocator.


Include Files
  • mkl.h
To improve performance of
Intel® oneAPI Math Kernel Library
, the Memory Allocator uses per-thread memory pools where buffers may be collected for fast reuse. The
function frees unused memory allocated by the Memory Allocator.
See the
Intel® oneAPI Math Kernel Library
Developer Guide
for details.
You should call
after the last call to
Intel® oneAPI Math Kernel Library
functions. In large applications, if you suspect that the memory may get insufficient, you may call this function earlier, but anticipate a drop in performance that may occur due to reallocation of buffers for subsequent calls to
Intel® oneAPI Math Kernel Library
Optimization Notice
Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.
Notice revision #20110804
This notice covers the following instruction sets: SSE2, SSE4.2, AVX2, AVX-512.

Usage of mkl_free_buffers with FFT Functions

DFTI_DESCRIPTOR_HANDLE hand1; DFTI_DESCRIPTOR_HANDLE hand2; void mkl_free_buffers(void); . . . . . . /* Using Intel MKL FFT */ Status = DftiCreateDescriptor(&hand1, DFTI_SINGLE, DFTI_COMPLEX, dim, m1); Status = DftiCommitDescriptor(hand1); Status = DftiComputeForward(hand1, s_array1); . . . . . . Status = DftiCreateDescriptor(&hand2, DFTI_SINGLE, DFTI_COMPLEX, dim, m2); Status = DftiCommitDescriptor(hand2); . . . . . . Status = DftiFreeDescriptor(&hand1); . . . . . . Status = DftiComputeBackward(hand2, s_array2)); Status = DftiFreeDescriptor(&hand2); /* Here you finish using Intel MKL FFT */ /* Memory leak will be triggered by any memory control tool */ /* Use mkl_free_buffers() to avoid memory leaking */ mkl_free_buffers();

Product and Performance Information


Performance varies by use, configuration and other factors. Learn more at