Are multicore-capable garbage collectors hard to write?
In this era of multicore computing, garbage collectors need to allow user threads (aka mutators ) to run in parallel on separate cores simultaneously in order to facilitate efficient shared memory parallel programming. There are two relevant phrases from garbage collection terminology here: Parallel GC means the garbage collector itself has been parallelised in order to speed up garbage collections. For example, a stop-the-world collector might traverse the heap in parallel when marking in an attempt to reduce pause times. Concurrent GC means the garbage collector runs at the same time as the user threads (aka mutators ). For example, Dijkstra's algorithm and derivatives like Doligez-Leroy use fine-grained synchronization to keep a concurrently-running collector apprised of the constantly-changing heap topology. However, we are talking about neither parallel GC nor concurrent GC but, rather, the simpler challenge of just allowing mutators to run in parallel. In the absence of any...