Isn't that just what it is? A performance?
Perform is a strange word. It's rooted in the Old French parfornir, "to do, carry out, finish, accomplish" -- par- implying completeness, -fornir meaning to furnish, as in to bring something to its wholeness, its finish. (Here's the entire etymology from the OED, if you're interested:
parfourmer, parfourmir, parfurmer, performer, performir, perfourmer, parforner, parfourner, parfurner, perforner, perfourner, perfournir, Anglo-Norman and Middle French parfornir, parfournir, parfurnir (French parfournir, now only in legal use in sense ‘to contribute (something) in addition to or as a replacement for (something else)’) to carry out, execute (an action, a promise) (c1170 or earlier in Anglo-Norman; frequently in legal use with object ‘will’, ‘judgement’, or similar (1291 or earlier)), to achieve, complete, finish (an action, also a concrete piece of work, e.g. a song, a building) (c1300 or earlier in Old French (Picardy)), to make, provide (payments, etc.) (14th cent. or earlier), to act (a play) (15th cent. or earlier), to supply (what is wanting) (late 14th cent. or earlier) < par-, per- (seead hoc. That isn't to say a performance can't be planned; it just operates best within a space of spontaneity and improvisation rather than rehearsal and memorization. It's in this sense that I can see what I spend the majority of my time doing as a kind of performance -- performing reading, performing writing, performing intelligence (which, importantly, is not the same thing as feigning or distrusting or proving intelligence); performing professionalism, performing relationships, performing interest; performing performance.
PER-prefix) + fornir, fourner, fournir, furnir FURNISHv. The Anglo-Norman forms with medial -m- show alteration after former, fourmer, fourmir, furmer, furmir FORMv.1 or forme, fourme, furme FORMn. Compare post-classical Latin performare to carry out (13th cent.). Compare later PERFURNISHv.)
The tightrope walker had begun his performance: he had stepped out of a small door and was walking over the rope, stretched between two towers and suspended over the market place and the people. When he had reached the exact middle of his course the small door opened once more and a fellow in motley clothes, looking like a jester, jumped out and followed the first one with quick steps.
"Forward, lamefoot!"he shouted in an awe-inspiring voice. "Forward, lazybones, smuggler, pale-face, or I shall tickle you with my heel! What are you doing here betwen towers? The tower is where you belong. You ought to be locked up; you block the way for one better than yourself." And with every word he came closer and closer; but when he was but one step behind, the dreadful thing happened which made every mouth dumb and every eye rigid: he uttered a devilish cry and jumped over the man who stood in his way. This man, however, seeing his rival win, lost his head and the rope, tossed away his pole, and plunged into the depth even faster, a whirlpool of arms and legs. The market place became as a sea when a tempest pierces it: the people rushed apart and over one another, especially at the place where the body must hit the ground.
// Nietzsche, Thus Spoke Zarathustra, Book I
For a tightrope walker, performance (or the ability to perform) exists in her position, in placing her center of gravity directly over her ankles for support.
And, perhaps more importantly, in forgetting the abyss of whooshing water open beneath her.