[racket-dev] gc vs assignment

From: Matthias Felleisen (matthias at ccs.neu.edu)
Date: Tue Aug 24 10:05:56 EDT 2010

Catching up with some mail. 

Neil wrote: 

> Avoiding allocation reduces GC collects, which reduces stutters and hitches.

My (possibly old) understanding of GC and mutation tell me that this is one of those prejudices that programmers should get rid of. Every mutation goes across an access barrier in a GC like ours and can thus be much more expensive than a lightweight allocation. This was certainly true for early generational collectors. I do know that the hordes of Java programmers who invaded GCLand forced GC builders to make C/C++-like programs in Java work reasonably fast with collectors and so collectors changed. 

Matthew, do you know what it's really like for us? 

Posted on the dev mailing list.