Re:Chris Lattner on garbage collection vs. Automatic Referen...
by hayley-patton on Saturday April 23, 2022 @10:00PM
(#31140597)
Some people refer to only tracing algorithms (mark-sweep, copying, etc) as "garbage collection". The best reason I can think of is marketing.
There are generational reference counting systems e.g. ulterior reference counting [1] and age-oriented collection [2]. "Tracing" usually refers to scanning a heap to work out liveness all at once, which reference counting doesn't do; though deferred reference counting scans the roots to collect, and ulterior reference counting traces a nursery. Deferring these (more common) updates to reference counts improves throughput considerably.
There are generational reference counting systems e.g. ulterior reference counting [1] and age-oriented collection [2]. "Tracing" usually refers to scanning a heap to work out liveness all at once, which reference counting doesn't do; though deferred reference counting scans the roots to collect, and ulterior reference counting traces a nursery. Deferring these (more common) updates to reference counts improves throughput considerably.
[1] https://people.cs.umass.edu/~emery/classes/cmpsci691s-fall20... [2] https://users.cecs.anu.edu.au/~steveb/pubs/papers/aogc-cc-20...