GXF job statistics

Holoscan v2.2.0

Holoscan can have the underlying graph execution framework (GXF) collect job statistics during application execution. Collection of these statistics causes a small amount of runtime overhead, so they are disabled by default, but can be enabled on request via the environment variables documented below. The job statistics will appear in the console on application shutdown, but can optionally also be saved to a JSON file.

The statistics collected via this method correspond to individual entities (operators) in isolation. To track execution times along specific paths through the computation graph, see the documentation on flow tracking instead.


The job statistics will be collected by the underlying Graph Execution Framework (GXF) runtime. Given that, the terms used in the report correspond to GXF concepts (entity and codelet) rather than Holoscan classes.

From the GXF perspective, each Holoscan Operator is a unique entity which contains a single codelet as well as its associated components (corresponding to Holoscan Condition or Resource classes). Any additional entities and codelets that get implicitly created by Holoscan will also appear in the report. For example, if an output port of an operator connects to multiple downstream operators, you will see a corresponding implicit “broadcast” codelet appearing in the report).

Collection of GXF job statistics can be enabled by setting HOLOSCAN_ENABLE_GXF_JOB_STATISTICS.

  • HOLOSCAN_ENABLE_GXF_JOB_STATISTICS : Determines if job statistics should be collected. Interprets values like “true”, “1”, or “on” (case-insensitive) as true (to enable job statistics). It defaults to false if left unspecified.

  • HOLOSCAN_GXF_JOB_STATISTICS_CODELET : Determines if a codelet statistics summary table should be created in addition to the entitty stastics. Interprets values like “true”, “1”, or “on” (case-insensitive) as true (to enable codelet statistics). It defaults to false if left unspecified.

  • HOLOSCAN_GXF_JOB_STATISTICS_COUNT : Count of the number of events to be maintained in history per entity. Statistics such as median and maximum correspond to a history of this length. If unspecified, it defaults to 100.

  • HOLOSCAN_GXF_JOB_STATISTICS_PATH : Output JSON file name where statistics should be stored. The default if unspecified (or given an empty string) is to output the statistics only to the console. Statistics will still be shown in the console when a file path is specified.

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