Index objects represent sets of things whose index can be computed from the data recorded in each packet. Index-object sets that are predefined include: Threads, Cpus, Samples, and Seconds. Other index objects may be defined either through the er_print indxobj_define command, issued directly or in a .er.rc file. In the Analyzer, you can define index objects by selecting Set Data Presentation from the View menu, selecting the Tabs tab, and clicking the Add Custom Index Object button.
For each packet, the index is computed and the metrics associated with the packet are added to the Index Object at that index. An index of -1 maps to the <Unknown> Index Object. All metrics for index objects are exclusive metrics, as no hierarchical representation of index objects is meaningful.