A thread local heap is an extension of the thread local area concept. GC can be implemented with several largish thread local heaps and a global heap. This is beneficial if most objects are temporary as well as thread local. In that case, they never need to be put on the global heap, which is subject to more synchronization. Usually, the cost of a thread local garbage collection policy is quite high for everything but quite specific applications. This is because both read barriers and write barriers are required to keep track of if an object is still thread local or if it has been exposed to other threads. There are however environments, such as in a specialized OS layer, where this overhead can be somewhat reduced.

See also Generational garbage collection and Thread local area.