SPEC OMP2012 Platform Settings for HP Integrity Intel-based systems

Operating System Tuning Parameters

OS Tuning

submit= MYMASK=`printf '0x%x' \$((1<<\$SPECCOPYNUM))`; /usr/bin/taskset \$MYMASK $command

When running multiple copies of benchmarks, the SPEC config file feature submit is sometimes used to cause individual jobs to be bound to specific processors. This specific submit command is used for Linux. The description of the elements of the command are:

• /usr/bin/taskset [options] [mask] [pid | command [arg] ... ]:
  taskset is used to set or retrieve the CPU affinity of a running process given its PID or to launch a new COMMAND with a given CPU affinity. The CPU affinity is represented as a bitmask, with the lowest order bit corresponding to the first logical CPU and highest order bit corresponding to the last logical CPU. When the taskset returns, it is guaranteed that the given program has been scheduled to a legal CPU.
  
  The default behavior of taskset is to run a new command with a given affinity mask:
  
  taskset [mask] [command] [arguments]
• $MYMASK: The bitmask (in hexadecimal) corresponding to a specific SPECCOPYNUM. For example, $MYMASK value for the first copy of a rate run will be 0x00000001, for the second copy of the rate will be 0x00000002 etc. Thus, the first copy of the rate run will have a CPU affinity of CPU0, the second copy will have the affinity CPU1 etc.
• $command: Program to be started, in this case, the benchmark instance to be started.

ulimit -s [n | unlimited] (Linux)

Sets the stack size to n kbytes, or unlimited to allow the stack size to grow without limit.

vm.max_map_count=-n (Linux)

The maximum number of memory map areas a process may have. Memory map areas are used as a side-effect of calling malloc, directly by mmap and mprotect, and also when loading shared libraries.

Performance Governors (Linux)

The in-kernel CPU frequency governors are pre-configured power schemes for the CPU. The CPUfreq governors use P-states to change frequencies and lower power consumption. The dynamic governors can switch between CPU frequencies, based on CPU utilization to allow for power savings while not sacrificing performance.

For the Performance Governor the CPU frequency is statically set to the highest possible for maximum performance.

On SUSE SLES 11 and 12 systems you can set the in-kernel CPU frequency governor for all CPUs to the Performance Governor with the following command:

• cpupower -c all frequency-set -g performance

Firmware / BIOS / Microcode Settings

Firmware Settings

One or more of the following settings may have been set. If so, the "Platform Notes" section of the report will say so; and you can read below to find out more about what these settings mean.

Intel Hyperthreading Options (Default = Enabled):

This feature allows enabling/disabling of logical processor cores on processors supporting Intel's Hyper-Threading Technology. This option may improve overall performance for applications that will benefit from higher processor core count.

Memory RAS Configuration (Default = RAS):

This option controls the configuration of memory reliability, availability and serviceability (RAS) features. When setting this option to Maximum Performance system performance is optimized. When setting this option to RAS (also known as lockstep mode) system reliability is enhanced with a degree of memory redundancy.