Properties

A Properties chunk provides a list of name-value pairs that define various properties of the server, the feed, the current run, or any other information that could be helpful for a user analyzing the trace. The TuningFork does not interpret the properties defined in the Properties chunk, it only presents them to the human analyst. The Properties chunk is a multiple-instance anytime chunk. Any number of chunks be sent at any time in the feed.

We recommend sending at least one Properties chunk during the initialization phase, to populate the TuningFork user interface with properties describing the feed early on. If more properties become available later (e.g. the running time of the application, a possible property, can be determined only after the application terminates), additional Properties chunks can be sent at that time. The TuningFork user interface combines the properties of all Properties chunks received so far. If a new Properties chunk redefines the value of a previously set property, the TuningFork reports the new value from that point on.

In our experience it is crucial for traces to contain all information that might be necessary to later reproduce an experiment. The Properties chunk is the best place to store this information. If TuningFork saves the feed to disk, the Properties chunk, like every other chunk, is stored and available for interpretation later on.