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7.4 Throttling

Throttling is a technique where measurment of certain events will be stopped if it crosses certain predefined thresholds. In the current implementation we throttle only user-level events (function calls) and we consider two different threshold for throttling:

An event will be throttled (or won't be measured any further) during runtime, if it was invoked more than ‘throttling-count’ and the average duration for that event was less than ‘throttling-duration’. The events specified in selective file will not be considered for throttling.

If a user function func1 is throttled, then it will appear as func1(throttled) in the performance data.

Throttling is enabled by default and can be disabled by passing --disable-throttling to ppwrun. The thresholds can be modified by passing --throttling-count=COUNT and --throttling-duration=DURATION to ppwrun.