Pause Free Garbage Collection [David W. Jeske]

This page serves as a summary of pause-free garbage collection implementations. If you know of an implementation or technique which is not present here, send me a note (jeske -at- chat -dot- net). For a detailed reference of garbage collection techniques, check out Ravenbrook.

Pause Free or Low Pause Collectors

Caml / OCaml - generational and incremental collection
Modula3 - incremental and generational collection available on some platforms
Visual Basic thru VB6 - reference counting
Python - reference counting plus generational cycle finding
Perl - reference counting (cycles cause memory leaks)
Io - tri-color incremental collector
PHP4 - reference counting

Other Collectors

JVM - while Java JVM implementations have the widest variety of options, they are all pausing collectors. The best seems to be Hotspot's partially concurrent collector. Bea also has a partially concurrent collector in JRockit 8.1.
MS .NET (C#, VB.NET) - Microsoft's v1.0 and v1.1 collectors are both pausing generational collectors
Mono/C# - uses the Boehm-Demers-Weiser libgc for generational collection. (allegedly supports incremental collection as well)
elisp - we're all familiar with the pauses in emacs/xemacs
Lua - a small embedded script language with a pausing collector