Loop Markup to Minimize Analysis Overhead

Issue

Running your target application with the

Intel® Advisor

can take substantially longer than running your target application without the

Intel® Advisor

.

Depending on an accuracy level and analyses you choose for a perspective, different overhead is added to your application execution time.

For example:

Runtime Overhead / Analysis	Survey	Characterization	Dependencies	MAP
Target application runtime with Intel® Advisor compared to runtime without Intel® Advisor	1.1x longer	2 - 55x longer	5 - 100x longer	5 - 20x longer

Solutions

Use the following techniques to skip uninteresting
loops and analyze only interesting
loops.

Select Loops by ID

Minimize collection overhead.

Applicable analyses:

Characterization with Trip Counts and FLOP collection enabled

, Dependencies, Memory Access Patterns.

Use when...

You want to perform a deeper analysis on only a few loops.

CLI environment: You cannot identify source file/line numbers, such as when you are analyzing a target application for which you do not have access to source code.

Prerequisites:

Run a Survey analysis.

advisor

CLI environment: Identify the loop IDs for the loops of interest.

advisor --report=survey --project-dir=./myAdvisorProj -- ./bin/myTargetApplication

Intel® Advisor

reports tend to be very wide. Do one of the following to generate readable reports:

Set your console width appropriately to avoid line wrapping.

Pipe your report using the appropriate truncation command if you care only about the first few report columns.

After performing the prerequisites, do one of the following:

Mark the loop(s) of interest by enabling the associated

checkbox on the

Survey Report

.

Then run a

Characterization with Trip Counts and FLOP collection enabled

, Dependencies, or Memory Access Patterns analysis.

Mark the loop(s) of interest using the CLI action option

-mark-up-list=<string>

when running a

Characterization with Trip Counts and FLOP collection enabled

, Dependencies, or Memory Access Patterns analysis. For example:

advisor --collect=tripcounts --flop --project-dir=./myAdvisorProj --mark-up-list=5,10,12 -- ./bin/myTargetApplication

There is essentially no difference between selecting loops by ID and selecting loops by source file/line in the GUI environment. The difference is in the CLI environment:

The

advisor

CLI action option

--mark-up-list=<string>

merely simulates enabling a GUI

checkbox; therefore it persists only for the duration of the

--collect

command.

The

advisor

CLI action

--mark-up-loops

and action option

-select=<string>

actually enables a GUI

checkbox; therefore it persists beyond the duration of the

-mark-up-loops

command and applies to downstream analyses, such as

Characterization with Trip Counts and FLOP collection enabled

, Dependencies, Memory Access Patterns.

Select Loops by Source File/Line Number

Minimize collection overhead.

Applicable analyses:

Characterization with Trip Counts and FLOP collection enabled

, Dependencies, Memory Access Patterns.

Use when...

You want to perform a deeper analysis on only a few loops.

CLI environment: You are analyzing a target application for which you have access to source code and can identify source file/line numbers.

Prerequisites:

Run a Survey analysis.

advisor

CLI environment: If necessary, identify the source file and line number for the loops of interest.

advisor --report=survey --project-dir=./myAdvisorProj -- ./bin/myTargetApplication

After performing the prerequisites, do one of the following:

Mark the loop(s) of interest by enabling the associated

checkbox on the

Survey Report

.

Then run a

Characterization with Trip Counts and FLOP collection enabled

, Dependencies, or Memory Access Patterns analysis.

Mark the loop(s) of interest using the

advisor

CLI action

--mark-up-loops

and action option

--select=<string>

. For example:

advisor --mark-up-loops --select=foo.cpp:34,bar.cpp:192 --project-dir=./myAdvisorProj -- ./bin/myTargetApplication

Then run a

Characterization with Trip Counts and FLOP collection enabled

, Dependencies, or Memory Access Patterns analysis.

You can also append and remove source file/line numbers using the

advisor

CLI action option

--append=<string>

and

--remove=<string>

respectively.

There is essentially no difference between selecting loops by ID and selecting loops by source file/line in the GUI environment. The difference is in the

advisor

CLI environment:

The

advisor

CLI action option

--mark-up-list=<string>

merely simulates enabling a GUI

checkbox; therefore it persists only for the duration of the

--collect

command.

The

advisor

CLI action

--mark-up-loops

and action option

--select=<string>

actually enables a GUI

checkbox; therefore it persists beyond the duration of the

--mark-up-loops

command and applies to downstream analyses, such as

Characterization with Trip Counts and FLOP collection enabled

, Dependencies, and Memory Access Patterns.

Select Loops by Criteria

Minimize collection overhead.

Applicable analyses: Dependencies, Memory Access Patterns.

Use when you want to perform a deeper analysis on loops chosen by criteria instead of by human input, such as when you are running the

Intel® Advisor

in batch mode or using automated scripts.

To implement in the

advisor

CLI environment, create a script similar to the following examples, which produce the same outcome. Use the

--loops

option to select loops by criteria:

Example 1:

advisor --collect=survey --project-dir=./myAdvisorProj -- ./bin/myTargetApplication
advisor --mark-up-loops --loops="scalar,has-issue" --project-dir=./myAdvisorProj -- ./bin/myTargetApplication
advisor --collect=dependencies --project-dir=./myAdvisorProj  -- ./bin/myTargetApplicaton

Example 2:

advisor --collect=survey --project-dir=./myAdvisorProj -- ./bin/myTargetApplication
advisor --collect=dependencies --loops="scalar,has-issue" --project-dir=./myAdvisorProj  -- ./bin/myTargetApplicaton

Quick Links

Recent Searches

Loop Markup to Minimize Analysis Overhead

Issue

Solutions

Select Loops by ID

Select Loops by Source File/Line Number

Select Loops by Criteria

Product and Performance Information

Sign In

Loop Markup to Minimize Analysis Overhead

Issue

Solutions

Select Loops by ID

Select Loops by Source File/Line Number

Select Loops by Criteria

Product and Performance Information