Intel® Math Kernel Library 11.1 Update 3 User's Guide
The most significant parameters in HPL.dat are N, NB, P and Q. Specify them as follows, as well as some other parameters:
P and Q - the number of rows and columns in the process grid, respectively.
P*Q must be the number of MPI processes that HPL is using.
For the hybrid offload version of the Intel Optimized MP LINPACK Benchmark, keep P and Q roughly the same size.
This setting is different from settings recommended for most HPL implementations, which usually recommend to choose P < Q and possibly with the 1:4 ratio.
NB - block size of the data distribution.
The table below shows recommended values of NB for 2nd and 3rd generation Intel® Core™ processors and for different numbers of Intel Xeon Phi coprocessors. The values may vary and depend on the PCI Express settings and performance of main memory.
|
No coprocessors |
1 coprocessor |
2 coprocessors |
3 coprocessors |
|---|---|---|---|
|
256 |
960 |
1024 |
1200 |
N - the problem size:
For homogeneous runs, choose N divisible by NB*LCM(P,Q), where LCM is the least common multiple of the two numbers.
For heterogeneous runs, refer to Heterogeneous Intel Optimized MP LINPACK Benchmark.
Note that increasing N usually increases performance, but the size of N is bounded by memory.
Other parameters.
To use Intel MKL BPUSH algorithm for horizontal broadcast, in line 23 of HPL.dat, set the BCASTs parameter to 6.
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