The most common and most likely answer to this crossword clue is the 3 letter word GIG
I've seen this crossword clue in Independent
G
I
G
More clues leading to the result GIG
- Musical performance that may go either way?
- Up-and-down performance?
- Performance of US serviceman, good
- Concert that's coming up just the same?
- Ultimately I'll leave musical concert
- Vehicle’s performance: up and down
- Most of a truism about computing performance
- Short musical performance
- Musical abridged for a single performance
Buddy explains!

The straight part
We know that "computing performance" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case computing performance = gig.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does GIG mean?
GIG noun- A performing engagement by a musical group; or, generally, any job or role, especially for a musician or performer.
- (by extension) Any job; especially one that is temporary; or alternately, one that is very desirable.
- A forked spear for catching fish, frogs, or other small animals.
- A two-wheeled horse-drawn carriage.
- (South England) A six-oared sea rowing boat commonly found in Cornwall and the Isles of Scilly.
- An open boat used to transport the captain of a ship, the captain's gig.
- A demerit received for some infraction of military dress or deportment codes.
- To fish or catch with a gig, or fish spear.
- To engage in musical performances.
- To make fun of; to make a joke at someone's expense, often condescending.
- To impose a demerit for an infraction of a dress or deportment code.
- Clipped form of gigabyte.
- Any unit having the SI prefix giga-
- A playful or wanton girl; a giglot.
- To engender.