User Guide

Contents

High Dependencies Bound-by

Symptoms

You see one or both of the following symptoms:
  • In the
    Summary
    tab of the HTML report, there is a high percentage of
    Dependecies
    in the
    Offloads Boudned-by
    pane.
  • A lot of code regions have the
    Dependency: Assumed
    value in the
    Dependency Type
    column of the metric table.

Cause

If you do not run the Dependencies analysis,
Intel® Advisor Beta
uses information about a loop dependencies from a compiler or from explicit code mark-up, for example, with a programming model (OpenMP*, DPC++, Threading Building Blocks). If there is not information in the compiler or the loop is not explicitly marked as parallel,
Intel® Advisor Beta
assigns
Dependency: assumed
type to it.
Loops with dependencies are not recommended for offloading.

Possible Solution

Do one of the following:
  • Run the Dependencies analysis:
    • Use the
      --markup generic
      option with
      collect.py
      .
    • Re-run the collection with the Dependencies analysis enabled.
  • If the Dependencies overhead is still high. you can skip the Dependencies analysis and use the
    --assume-parallel
    option with
    analyze.py
    to mark all code regions with assumed dependencies as
    Parallel
    .

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