Fujitsu Siemens Computers SPEC CPU2006 Flag Description

Compilers: Intel(R) C++ Compiler and Intel(R) Visual Fortran Compiler for applications running on Intel(R) 64, Version 10.1
Operating system: Windows Vista Ultimate, x64 Version
Last updated: 11-Dec-2007

The text for many of the descriptions below was taken from the documentation of the Intel Compilers. This documentation is copyright © 2007 Intel Corporation. All Rights Reserved.
The original documentation is distributed with the Intel compilers.


Sections

Selecting one of the following will take you directly to that section:


Optimization Flags

HEADER for OPTIMIZATION


Portability Flags

HEADER for PORTABILITY


Compiler Flags

HEADER for COMPILER


System and Other Tuning Information

Platform settings

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

OMP_NUM_THREADS

Sets the maximum number of threads to use for OpenMP* parallel regions if no other value is specified in the application. This environment variable applies to both -openmp and -parallel (Linux and Mac OS X) or /Qopenmp and /Qparallel (Windows). Example syntax on a Windows system with 8 cores:
set OMP_NUM_THREADS=8
Default is the number of cores visible to the OS.

KMP_AFFINITY

KMP_AFFINITY = , starting-core-id specifies the static mapping of user threads to physical cores, for example, if you have a system configured with 8 cores, OMP_NUM_THREADS=8 and KMP_AFFINITY=physical,2. Thread 0 will mapped to core 2, thread 1 will be mapped to core 3, and so on in a round-robin fashion.

Hardware Prefetch:

This BIOS option allows the enabling/disabling of a processor mechanism to prefetch data into the cache according to a pattern-recognition algorithm.

In some cases, setting this option to Disabled may improve performance. Users should only disable this option after performing application benchmarking to verify improved performance in their environment.

Adjacent Sector Prefetch:

This BIOS option allows the enabling/disabling of a processor mechanism to fetch the adjacent cache line within an 128-byte sector that contains the data needed due to a cache line miss.

In some cases, setting this option to Disabled may improve performance. Users should only disable this option after performing application benchmarking to verify improved performance in their environment.

Snoop Filter Enabled/Disabled:

The Snoop Filter is designed to reduce system bus utilization coming from cache misses. On the Intel 5000X and 5400 chipset, it is built as a cache structure able to minimize unnecessary snoop traffic.
When enabled, it can lead to significant memory performance improvements for several workstation applications on suitable memory configurations.