Tutorial: Finding Hotspots - C++ Sample Code (Windows* OS)

Tutorial

Contents

Resolve Issue

In the
Source
 window, the
multiply1
 function was identified as a Memory Bound hotspot. To solve this issue, do the following:
The proposed solution is one of the multiple ways to optimize memory access and is used for demonstration purposes only.
  1. Open the
    multiply.h
     file from the sample code source files. You can find the source files in the following location:
    C:\Users\
    <user>
    \Documents\VTune\sample\matrix\src
    .
    If you are using Microsoft Visual Studio* as your code editor, a project is available in the
    C:\Users\
    <user>
    \Documents\VTune\sample\matrix\vc15 (vc14 or vc12)
     directory.
    For this sample, the
    multiply.h
     file is used to define the functions used in the
    multiply.c
     file.
  2. In line 36, replace the
    multiply1
     function name with the
    multiply2
     function.
    This new function uses the loop interchange mechanism that optimizes the memory access in the code, which can be seen in the
    multiply.c
     file.
  3. Save files and rebuild the project using the compiler of your choice.
    For example, from the Visual Studio menu, select
    Build
    Rebuild matrix
    .
Optimization Notice
Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.
Notice revision #20110804

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804