Developer Guide


Call Description Line

Intel® oneAPI Math Kernel Library
Verbose mode, each verbose-enabled function called from your application prints a call description line. The line begins with the
character string and uses spaces as delimiters. The format of the rest of the line may change in a future release.
The following table lists information contained in a call description line and provides available links for more information:
Related Links
The name of the function.
Although the name printed may differ from the name used in the source code of the application (for example, the
prefix of CBLAS functions is not printed), you can easily recognize the function by the printed name.
Values of the arguments.
  • The values are listed in the order of the formal argument list. The list directly follows the function name, it is parenthesized and comma-separated.
  • Arrays are printed as addresses (to see the alignment of the data).
  • Integer scalar parameters passed by reference are printed by value. Zero values are printed for
  • Character values are printed without quotes.
  • For all parameters passed by reference, the values printed are the values
    returned by the function
    . For example, the printed value of the
    parameter of a LAPACK function is its value after the function execution.
  • For verbose-enabled functions in the ScaLAPACK domain, in addition to the standard input parameters, information about blocking factors, MPI rank, and process grid is also printed.
Time taken by the function.
  • The time is printed in convenient units (seconds, milliseconds, and so on), which are explicitly indicated.
  • The time may fluctuate from run to run.
  • The time printed may occasionally be larger than the time actually taken by the function call, especially for small problem sizes and multi-socket machines.
    To reduce this effect, bind threads that call
    Intel® oneAPI Math Kernel Library
    to CPU cores by setting an affinity mask.
Managing Multi-core Performance for options to set an affinity mask.
Value of the
environment variable.
The value printed is prefixed with
Value of the
environment variable.
The value printed is prefixed with
Status of the
Intel® oneAPI Math Kernel Library
memory manager.
The value printed is prefixed with
Avoiding Memory Leaks in
for a description of the
Intel® oneAPI Math Kernel Library
memory manager
OpenMP* thread number of the calling thread.
The value printed is prefixed with
Values of
Intel® oneAPI Math Kernel Library
environment variables defining the general and domain-specific numbers of threads, separated by a comma.
The first value printed is prefixed with
The following is an example of a call description line:
MKL_VERBOSE DGEMM(n,n,1000,1000,240,0x7ffff708bb30,0x7ff2aea4c000,1000,0x7ff28e92b000,240,0x7ffff708bb38,0x7ff28e08d000,1000) 1.66ms CNR:OFF Dyn:1 FastMM:1 TID:0 NThr:16,FFT:2
The following information is not printed because of limitations of
Intel® oneAPI Math Kernel Library
Verbose mode:
  • Input values of parameters passed by reference if the values were changed by the function.
    For example, if a LAPACK function is called with a workspace query, that is, the value of the
    parameter equals -1 on input, the call description line prints the result of the query and not -1.
  • Return values of functions.
    For example, the value returned by the function
    is not printed.
  • Floating-point scalars passed by reference.

Product and Performance Information


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