sutton036

Eight years ago I answered a question on Stack Overflow about the suitability of OCaml and Haskell for soft real-time work like visualization: " for real-time applications you will also want low pause times from the garbage collector. OCaml has a nice incremental collector that results in few pauses above 30ms but, IIRC, GHC has a stop-the-world collector that incurs arbitrarily-long pauses " My personal experience has always been that RAII in C++ incurs long pauses when using non-trivial data (i.e. nested, structured, collections of collections of collections, trees, graphs and so on), non-deferred reference counting has the same problem for the same reason, tracing garbage collectors like OCaml work beautifully but there are many notoriously bad tools like Java that have given tracing garbage collection a bad name. Now that I am revisiting this issue I am surprised to find many individuals and organisations repeating exactly the same experimental tests that I did and coming...

Our previous post caused some controversy by questioning the validity of some commonly-held beliefs. Specifically, the beliefs that reference counting (RC) always requires less memory than tracing garbage collection (GC) and that tracing GCs require 3-4x more memory in order to perform adequately. We presented a benchmark written in Swift and OCaml and noted that the RC'd Swift implementation ran over 5x slower and required over 3x more memory than the tracing GC'd OCaml implementation. This observation disproves these beliefs in their strong form and even brings into question whether there is even any validity in the weak forms of those beliefs. After all, we have never seen any empirical evidence to support these beliefs in any form. We received a lot of criticism for that post. The vast majority of the criticism was not constructive but two valid points did arise. Firstly, although our result was anomalous it would be more compelling to see the benchmark repeated across a w...

The way software developers cling to folklore and avoid proper experimental testing of hypotheses really bothers me. I think perhaps the worst branch of computer science still riddled with myths and legends is memory management. Despite over half a century of research on garbage collection showing that reference counting is inferior to tracing garbage collections algorithms (even when almost all GC research restricts consideration to Java when much better algorithms have been known for years) there are still many people who claim otherwise. C++ developers obviously still believe that reference counted smart pointers are superior to tracing garbage collection but now other people are doing it too. People who should know better. This situation recently reared its ugly head again when Apple released a promising new programming language called Swift that shuns tracing garbage collection in favor of reference counting. Now, there are logical reasons for Apple to have chosen reference count...