Limiting Data Collection

Limiting data collection prevents from collecting a large amount of data that may slow down the data processing. For example, it may happen when running Concurrency and Locks and Waits analyses on frequently contended applications or when analyzing long profiles.

Typically, the default maximum amount of raw data used by the Intel® VTune™ Amplifier for the result file is enough to identify a problem.

To limit the amount of raw data, use any of the following options:

• Setting the Maximum Possible Result File (in MB)

• Setting the Analysis Timer for the Last Seconds of Collection

Setting the Maximum Possible Result File (in MB)

Use the data-limit command line option to limit the amount of raw data to be collected by setting the maximum possible result size (in MB). VTune Amplifier starts collecting data from the beginning of the target execution and suspends data collection when the specified limit for the result size is reached. For unlimited data size, specify 0.

$ amplxe-cl -collect <analysis_type> -data-limit=<value> -- <target>

Example

Start a Basic Hotspots analysis on the specified target and limit the result size to 200 MB.

$ amplxe-cl -collect hotspots -data-limit=200 -- home/test/myApplication

Setting the Analysis Timer for the Last Seconds of Collection

Use the ring-buffer command line option to limit the amount of raw data to be collected by setting the timer that enables the analysis only for the last seconds before the target or collection is terminated. For example, if you specify 2 seconds as a time limit, the VTune Amplifier starts the data collection from the very beginning but saves the collected data only for the last 2 seconds before you terminate the collection.

$ amplxe-cl -collect <analysis_type> -ring-buffer=<value> -- <target>

Example

Enable an Advanced Hotspots analysis on the specified target for the last 10 seconds before the collection is terminated.

$ amplxe-cl -collect advanced-hotspots -ring-buffer=10 -- home/test/myApplication