Optimizing for Intel® Xeon Processors

Optimization Steps

The key to performance measurement is two-fold, know exactly what you are measuring and collect your baseline data. Next, profile your application and identify a specific and realistic performance goal based on the profiling data. Follow these steps to optimize your software.

Vectorization Toolkit

Fundamental Concepts

The Intel Compilers provide a number of features for generating vectorized code. Auto-vectorization is the method used by the Intel Compilers to generate vectorized code for a given application without requiring code changes. Developers can also implement simple coding changes in the source code to enforce vectorization behavior. 

Intel Compiler Auto-vectorization (C++ | Fortran)

Vectorization Essentials

Common Vectorization Tips

Performance Essentials with OpenMP 4.0 Vectorization

Intermediate Techniques

Proven techniques for code optimizations and change recommendations are listed here. Note that these recmonndations depend entirely upon the application. 

Fortran Array Data and Arguments and Vectorization

Data Alignment to Assist Vectorization

Program Optimization through Loop Vectorization

Outer Loop Vectorization

Random Number Function Vectorization

Optimization Reports

Code changes may be required in order to facilitate vectorization even further. Once a developer has made changes to the code, how does one that the changes elicit the expected behavior? Use of special compiler optimization reports to guide source code changes and verify that the code does indeed vectorize.

Vectorization and Optimization Reports

Overview of Vectorization Reports and the -vec-report6 Option

Advanced Methods

The techniques offering the most control require greater application knowledge and skill in knowing where they should be applied. But these more intensive techniques, such as intrinsics, can result in greater performance when properly used.

Getting Started with Intel® Cilk™ Plus SIMD Vectorization and SIMD-enabled Functions

Outer Loop Vectorization via Intel Cilk Plus Array Notations

Intel Intrinsics Guide

References

Intel® Fortran Vectorization Diagnostics

Vectorization Diagnostics for Intel(R) C++ Compiler

For more complete information about compiler optimizations, see our Optimization Notice.