5 Storage Management in Common Lisp

5.3 Garbage collection

Liquid Common Lisp has two garbage-collecting programs to reclaim storage space, the Ephemeral Garbage Collector and the Dynamic Garbage Collector. In general, you should keep both programs enabled during development. Ephemeral garbage collection is faster and less noticeable than dynamic garbage collection and can reduce the number of dynamic garbage collections. It is thus particularly useful under the following circumstances:

when a program is creating and discarding many objects, such as when a program is processing lists withappend ormapcar
when a machine has relatively little physical memory or when paging is slow, as it is across a network or on a slow disk
when you are using or developing an interactive application in which long pauses for garbage collection would be distracting

Ephemeral garbage collection might not be as useful under the following circumstances:

when a program manipulates many pointers and garbage collection is not reclaiming much storage
when a machine has a relatively large amount of physical memory and is connected to a fast paging device
when you are working with efficient production code that does not create much garbage

The following sections provide more detailed information about the two garbage collectors, including how to turn them off.

5.3.1 - The Dynamic Garbage Collector
5.3.2 - The Ephemeral Garbage Collector

The User's Guide - 9 SEP 1996

Generated with Harlequin WebMaker