Tutorial: Where to Add Parallelism with Intel® Advisor 2015 and a C/C++ Sample
To predict the maximum parallel performance speedup of your target based on the added Intel Advisor annotations:
Each step is described more fully below.
Under
3. Check Suitability in the
Advisor Workflow, click the
button to collect Suitability data while the target executes.
During the Suitability analysis, the
Intel Advisor displays a window similar to the following.
You can ignore any warnings about missing debugging symbols during this tutorial.
After the Suitability tool finalizes the data, the
Intel Advisor displays a window similar to the following.
The Maximum Program Gain For All Sites value shows the predicted maximum speedup of our target based on Intel Advisor annotations and currently selected modeling parameters. Over a 6x speedup is good! |
||||||||||||||||||||||||||||||
This grid shows various metrics for each parallel site based on currently selected modeling parameters, including the site's Impact to Program Gain. Our target has a single parallel site - the solve parallel site, as identified in the Site Label column. |
||||||||||||||||||||||||||||||
Use these modeling parameter drop-downs to experiment with different hardware configurations and parallel frameworks.
|
||||||||||||||||||||||||||||||
The Scalability of Maximum Site Gain diagram graphically shows the predicted maximum speedup for the solve parallel site in different scaling scenarios based on currently selected modeling parameters.
|
||||||||||||||||||||||||||||||
Use the Loop Iterations (Task) Modeling sliders and the Apply button to experiment with different iteration counts and instance durations. |
||||||||||||||||||||||||||||||
Use the Runtime Modeling checkboxes to experiment with predicted maximum speedup if you plan to use parallel framework code constructs to address parallel overhead, lock contention, or task chunking; or if you plan to tune parallel code after you implement parallelism. |
||||||||||||||||||||||||||||||
This area shows issues that generally prevent better parallel performance. A green bar is good; it means this issue is not negatively impacting predicted maximum speedup. A yellow or red bar is not good. |
||||||||||||||||||||||||||||||
The Site Details area shows information about the solve parallel site and the setQueen task within that parallel site. |
Notice how your screen changes if you choose a
Target System of
Intel Xeon Phi or
Offload to Intel Xeon Phi.
|
The Scalability of Maximum Site Gain diagram graphically shows the predicted performance of the manycore parallel coprocessor and its host CPUs. For many applications, the number of task instances does not scale enough to fully utilize the many cores of the parallel coprocessor. An application that is ready for an Intel Xeon Phi coprocessing system has a bulls-eye in the green part of the diagram. A bulls-eye in the gray part of the diagram indicates an application that is not ready for an Intel Xeon Phi coprocessing system; in such cases, try modeling another type of Target System. |
|
Use the Intel Xeon Phi Advanced Modeling checkbox, fields, and the Apply button to model the expected speedup if you plan to modify your parallel code to improve vector parallel execution. TipThese modeling parameters are fully explained in Intel Advisor Help. |
Try experimenting now to see the impact of various modeling parameters on predicted maximum speedup throughout the Suitability Report.
Click
Summary on the navigation toolbar to re-open the
Summary window. Notice the
Intel Advisor added more data to this dashboard.
This area summarizes the maximum parallel performance speedup. It also provides easy access to the Suitability Report window and your sources. Try clicking the Maximum Site Gain link now. Then return to the Summary window and try clicking the Parallel Site link. The question marks for detected Correctness Problems mean you have not yet collected any Correctness data. |
|
In addition to the newly acquired information from the Suitability Report, the dashboard still shows data from the Survey Report. |
|
You now have collection data from two of the three Intel Advisor analysis tools. |