ACROBATICS
The experience gained from falling is tied directly to damage done by the fall. Each half heart of damage earns 120xp from a fall with no roll, or 80xp from a fall where a roll or gracefull roll was executed.
Damage before the roll/gracefull roll damage reduction is used to calculate the XP gain. If the fall is fatal, no XP is earned. Because a player has a maximum of 20 health, the maximum XP you can earn in a single fall is 2280 (19 * 120), or 2800 from a gracefull roll fall ( (19 + 16) * 80 ).

Currently, a fall with Feather Falling armor equipped will net the same XP as if you didn't have the armor on, but without suffering the full damage. Because of this, you will also earn no XP for a fall that would have killed you if you didn't have this armor equipped