Yadro Vesnin Flags file

Shell, Environment, and Other Software Settings

• Environment variables that can be set before the run:

  XLFRTEOPTS=intrinthrds=1 : Causes the Fortran runtime to only use a single thread.
  

• To reserve 16000 huge pages out of the physical memory pool, issue the following command,

  echo 16000 > /proc/sys/vm/nr_hugepages
  

  or

  echo 16000 > /proc/sys/vm/nr_overcommit_hugepages
  

  to allocate from the dynamic hugepage pool. This can be done in both Red Hat and Suse Enterprise, since both distributions implements Transparent Huge Pages (THP). THP is an abstraction layer that automates most aspects of creating, managing and using huge pages, and can currently only map anonymous memory regions such as heap and stack space.

Operating System Tuning Parameters

• ulimit -s unlimited
  Sets the maximum stack size to "unlimited".
• Simultaneous Multi-Threading (SMT) mode was set to SMT4

   ppc64_cpu --smt=4 
  

  ppc64_cpu command is used to display and set cpu characteristics on PowerPC platforms.

  Options:
         --smt  Display  the  current  smt setting for the system. The output will state whether smt is off indicating there is only one thread per core online, smt is on indicating that all threads of every
                core is online, the smt is in a mixed state indicating that the number of threads online varies per core, or SMT=X indicating a specific smt state.
         --smt=value
                Set the smt state for each core to the specified value.
  
  

Firmware / BIOS / Microcode Settings

• Intelligent Energy Optimizations

Intelligent Energy Optimization capabilities enable the POWER8 processor to operate at a higher frequency for increased performance. This processor / firmware feature maximizes performance as thermal conditions allow and enabled by default in firmware.