Tutorial: Where to Add Parallelism with Intel® Advisor 2015 and a Fortran Sample
To discover parallel opportunities in serial code:
Each step is described more fully below.
To start a Survey analysis:
If the
Advisor Workflow is not currently displayed, click the
icon on the
Intel Advisor toolbar to open it.
Under
1. Survey Target in the
Advisor Workflow, click the
icon to collect Survey data while the target executes.
During the Survey analysis, the
Intel Advisor displays a window similar to the following.
You can ignore any warnings about missing debugging symbols during this tutorial.
The navigation toolbar lets you navigate among various result tab windows. If you see >> and << scroll controls, click them to see more window options. |
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During collection, the main area of the Survey Report shows collection progress and milestones, and runtime performance characteristics. The Collection Log pane shows collection informational, warning, and error messages. Notice you can redirect non-GUI application output to the Application Output pane. |
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The command toolbar lets you control collection and analysis. For example: You can skip uninteresting code regions by temporarily stopping data collection while the target continues to run and then resuming data collection (Pause and Resume buttons); stop target execution, analysis, and data collection, finalize the partially collected data, and display the result (Stop button); cancel target execution, analysis, and data collection, discard the collected data, and skip finalization (Cancel button). You can also use the Command Line button to view and copy the equivalent advixe-cl command and options to run this Survey analysis. |
This tutorial explains only how to use Intel Advisor tools from the Intel Advisor GUI.
After the Survey tool finalizes the data, the
Intel Advisor displays the
Survey Report and an infotip in the top left corner. Close the infotip to display a window similar to the following.
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The
Function Call Sites and Loops column shows an extended top-down call tree of our target, starting with the main entry point. Each function or loop appears on a separate row. A loop is indicated by a
The Total Time % column starts in the top line with a value of 100%. The Total Time column shows the time spent in a function or loop and all functions called from it. A row with a large Total Time % and multiple children with smaller total times is a possible candidate for parallelism. The Self Time column shows how much time was spent in the function or loop. Loops or functions with significant self time values are possible candidates for distributing work. The Source Location column shows the source file and line number associated with the location in the call tree. The
Hot Loops column and
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The Survey Report toolbar helps you quickly locate hot loops and view the Survey Source window for the currently selected row. |
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The
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The Annotations Example (annotations assistant) area, which is closed in this screenshot, shows various annotation samples and build settings you can copy directly into your editor. We will discuss annotation examples later in this tutorial. |
To dig deeper into the first hot loop, double-click the associated row to display a
Survey Source window similar to the following.
The File pane initially shows the source code and time values for the first hot loop. |
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The Call Stacks and Loops pane shows the call stack for the first hot loop. Clicking a row in the Call Stack with Loops pane displays the associated code in the File pane. Try clicking a row in this pane now. |
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The Annotations Example (annotations assistant) area, which is open in this screenshot, shows an annotation code snippet for a simple loop structure. We will discuss annotation examples later in this tutorial. |
Click the X beside Survey Source on the navigation toolbar to close the Survey Source window.
Click
Summary on the navigation toolbar to open a
Summary window similar to the following. Think of this window as a
dashboard to which the
Intel Advisor adds data each time you run
Intel Advisor tools.
This area summarizes possible loops where you might add parallelism. It also provides easy access to the Survey Report window and your sources. Try clicking a Loop link now. Then return to the Summary window and try clicking a Source Location link. |
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You currently have collection data from only one of the three Intel Advisor analysis tools. That will change very soon. |