Investigating serial code

To investigate the performance of a serial code named serial_prog.x on HPCx the LoadLeveler script should contain the line

  /usr/local/packages/actc/hpmtk/pwr4/bin/hpmcount serial_prog.x

This will analyse the performance of your program with HPMCOUNT's default settings and write the results of HPMCOUNT to the standard output.

Pitfall: If serial code has been compiled using the mp-prefix, e.g. mpxlf instead of xlf in the case of a Fortran-code or mpxlc instead of xlc in the case of a C-code, the above statement will automatically invoke poe in a way that HPMCOUNT will investigate the performance of poe. There are two solutions to this

• Recompile without the mp-prefix
• Run as a single-processor parallel job by calling

    poe /usr/local/packages/actc/hpmtk/pwr4/bin/hpmcount serial_prog.x