Instruments can visualize retain cycles under ARC in a graphically interesting way. I also remember that a few days ago I spotted the "Cycles" view in Instruments by accident.
Now where I started using ARC, suddenly I'm not able to find that anymore. The Allocations and VM Tracker instruments don't offer it, and the Leaks instrument either.
What must I do in order to see retain cycles?
Found a screenshot as evidence:
Using Xcode 4.2.1, I found the it in "Leaks", under "Cycles & Roots". However, I've found it less than useful when using ARC. It does detect CF leaks and apparently I'm leaking a recursive block, which I can't do anything about, but I've had to root out several retain cycles that Leaks never found. For finding retain cycles, I recommend using "Allocations" and running several heap shots between performing the action you suspect of 'leaking'. You then then look through the interim heap shots to find the culprit.
来源：https://stackoverflow.com/questions/8852451/how-to-activate-cycles-reporting-in-instruments-under-arc