Suitability Report, Site Details, Task Row

If you choose a Target System of CPU, to view detailed characteristics of the selected site and its tasks and locks, click the Site Details tab. The Task row shows the statistics for that task.

You can reduce Task overhead by combining multiple task executions into a single task execution, for example by:

  • Lexically merging two tasks into one.

  • Enabling chunking. Chunking means that the parallel framework merges several tasks into a single task, with little or no overhead between them. For instance, if tasks are loop iterations, chunking would execute several iterations together (as a chunk) before heavyweight task control is performed. Chunking is typically implemented when you convert to a parallel framework by using an Intel® TBB parallel_for() instance, an OpenMP* C/C++ pragma #pragma omp parallel for, or the OpenMP* Fortran directive !$omp parallel do.

Note

If you see an Annotation Label named _too_deep_, this indicates that the call behavior of your program results in nesting of site and/or task annotations more deeply than Intel Advisor can handle. The deeper occurrences have all been merged into this _too_deep_ pseudo-site. This can indicate a problem with the placement of the annotation pair. For example, deep recursions or not executing site-end or task-end annotations can result in such nesting.

For Each Site, Decide Whether to Modify or Keep Annotations

Use the Suitability Report window to view the predicted parallel performance of each parallel site and its impact on the Maximum Program Gain for All Sites. For example, if a site either has a Site Gain of less than 1.0 or does not contribute to Maximum Program Gain for All Sites, modify or remove its annotations. In contrast, any site that contributes to Maximum Program Gain for All Sites should be kept. For most sites, carefully examine the annotations, overhead assumptions, and related code.

In the upper-right part of the Suitability Report pane, if multiple parallel sites were detected during target execution, select a different Site row to display its details.

Implementing Modeling Assumptions Later When Adding Parallel Code

In the lower-right part of the Suitability Report under Runtime Modeling, changing a checkmark does not resolve an issue - it configures the modeling of your proposed parallel program execution. To implement the modeled improvements indicated by the check boxes, use specific parallel framework constructs in the Add Parallel Framework step of the workflow and consider tuning your parallel code.

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