40.5. Analyzing the Data

40.5. Analyzing the Data

Periodically, the OProfile daemon, oprofiled, collects the samples and writes them to the /var/lib/oprofile/samples/ directory. Before reading the data, make sure all data has been written to this directory by executing the following command as root: 

opcontrol --dump

Each sample file name is based on the name of the executable. For example, the samples for the default event on a Pentium III processor for /bin/bash becomes: 

\{root\}/bin/bash/\{dep\}/\{root\}/bin/bash/CPU_CLK_UNHALTED.100000

The following tools are available to profile the sample data once it has been collected:

Use these tools, along with the binaries profiled, to generate reports that can be further analyzed.

Warning

The executable being profiled must be used with these tools to analyze the data. If it must change after the data is collected, backup the executable used to create the samples as well as the sample files.

Samples for each executable are written to a single sample file. Samples from each dynamically linked library are also written to a single sample file. While OProfile is running, if the executable being monitored changes and a sample file for the executable exists, the existing sample file is automatically deleted. Thus, if the existing sample file is needed, it must be backed up, along with the executable used to create it before replacing the executable with a new version. Refer to Section 40.4, “Saving Data” for details on how to backup the sample file.


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