Developer Guide

Contents

Configuring Parameters

The most significant parameters in
HPL.dat
are
P, Q, NB
, and
N
. Specify them as follows:
  • 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.
    Choose
    P
    Q
    .
  • NB
    - the block size of the data distribution.
    The table below shows recommended values of
    NB
    for different Intel® processors:
    Processor
    NB
    Intel® Xeon® Processor X56*/E56*/E7-*/E7*/X7* (codenamed Nehalem or Westmere)
    256
    Intel Xeon Processor E26*/E26* v2 (codenamed Sandy Bridge or Ivy Bridge)
    256
    Intel Xeon Processor E26* v3/E26* v4 (codenamed Haswell or Broadwell)
    192
    Intel® Core™ i3/i5/i7-6* Processor (codenamed Skylake Client)
    192
    Intel® Xeon Phi™ Processor 72* (codenamed Knights Landing)
    336
    Intel Xeon Processor supporting Intel® Advanced Vector Extensions 512 (Intel® AVX-512) instructions (codenamed Skylake Server)
    384
  • N
    - the problem size:
    Increasing
    N
    usually increases performance, but the size of
    N
    is bounded by memory. In general, you can compute the memory required to store the matrix (which does not count internal buffers) as 8*
    N
    *
    N
    /(
    P
    *
    Q
    ) bytes, where
    N
    is the problem size and
    P
    and
    Q
    are the process grids in
    HPL.dat
    . A general rule of thumb is to choose a problem size that fills 80% of memory.
Product and Performance Information
Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.
Notice revision #20201201

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.