User Guide

Contents

Why Not Offloaded: Total Time is Too Small for Reliable Modeling

Symptoms

A code region of interest has
Total time is too small for reliable modeling
as a reason why it is not offloaded.

Cause

This can happen if the execution time of a code region or a whole loop nest is less than 0.02 seconds. In this case,
Offload Advisor
cannot estimate the speedup correctly and say if it is worth to offload the code regions because its execution time is close to the sampling interval of the
Intel® Advisor Beta
.

Possible Solution

If you want to check the profitability of offloading code regions with total time less than 0.02 seconds, use the
--loop-filter-threshold=0
option when running performance modeling with
analyze.py
to model such small offloads.
For example:
advixe-python <APM>/analyze.py <project-dir> --loop-filter-threshold=0 [options]
Replace
<APM>
with
$APM
on Linux* OS or
%APM%
on Windows* OS.

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 reserverd 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