The term for the inverse of the quantity of resources consumed by a computation, as defined by some metric.

Performance is traditionally measured in a context where only statically, separately-compiled systems are known, only "run-time" performance matters, and not the time spent by hundreds of programmers waiting for big systems to compile.

The Tunes concept of performance takes into account that we want abstraction levels of various kinds and often relatively-online compilation. So the amount of resources consumed not only has a metric, but a window within which it is considered, since ultimately there are no a priori boundaries between system components.

Tunes also takes into account the performances of meta-level operations, which are usually strict overhead in normal systems, but may be amortized in Tunes through partial evaluation. The overall benefit of Tunes would be that this technique could be extended down into system-level components as well.