Manage analysis duration for best results on short-running targets, or to minimize collection overhead on longer-running targets.
Use the amplxe-cl command interface to minimize duration while optimizing the analysis process.
Use Default Duration
Intel® VTune™ Amplifier provides predefined general analysis types to keep overhead to a reasonable level. The option reference topic for the collect action identifies analysis types that are recommended as starting points; and points out some more advanced analysis types that have higher overhead.
To view all the analysis types that are available for your processor, use the command line help:
> amplxe-cl -help collect
Adjust Collection Duration to Application
The sampling interval determines how much data is collected. The default sampling interval is short, which is appropriate for targets that complete in 1 - 15 minutes.
If your target runs shorter or longer than this, use the target-duration-type action-option to set the appropriate duration type, which adjusts the sampling interval.
If the target takes less than 1 minute to run, specify veryshort.
If the target takes 15 minutes to 3 hours to run, specify medium.
If the target takes over 3 hours, specify long.
For hardware event-based analysis types, a multiplier applies to the configured Sample After value.
Perform a Hotspots analysis in the user-mode sampling mode using a medium sampling interval that is appropriate for targets with a duration of 15 minutes to 3 hours.
$ amplxe-cl -collect hotspots -target-duration-type medium -- myApp
Manually Interrupt and Restart Analysis
To pause an analysis manually, open a new terminal and use the command action with the pause argument, being sure to specify the result directory. The target process continues to run, but data collection is paused.
$ amplxe-cl -command pause -result-dir results/r002hs
To resume analysis, use the command action with the resume argument.
$ amplxe-cl -command resume -r results/r002hs
To stop analysis altogether, use the command action with the stop argument. Once analysis is stopped, it cannot be resumed.
$ amplxe-cl -command stop -r results/r002hs
Configure Collection Duration
VTune Amplifier offers other ways to limit the analysis process. To stop analysis at a specified time after initiating target execution, use the duration option.
amplxe-cl -collect <analysis_type> -duration=<value> -- <target>
<analysis_type> is the type of analysis to run
<value> is the duration in seconds
<target> is the target to analyze
To start the analysis in the paused mode or pause the collection during the analysis, refer to Pause Collection from the Command Line section.
Example 1: Ending analysis after specified time
Start a Hotspots analysis of myApplication and end analysis after 60 seconds.
$ amplxe-cl -collect hotspots -duration=60 -- /home/test/myApplication
Example 2: Running an unlimited duration analysis
Run an unlimited duration Hotspots analysis, which will run until you stop it.
$ amplxe-cl -collect hotspots -duration=unlimited -result-dir results/r002hs