[Gc] 6.2 to 6.4 change?

Nikhil Swamy nswamy at cs.umd.edu
Fri Apr 22 11:43:01 PDT 2005


I just switched from gc6.2.4-alpha to gc6.4 and have noticed a pretty
dramatic change in behavior. I'm running the same benchmark with only
a change in the gc version, with the same configure parameters on both
gc versions. Here's is what I notice:

The reserved space size with 6.2.4 grows upto 750KB, there are around
950 collections, and this takes around 800 clock units to run. Running
with 6.4 the reserved space grows to about 20MB, there are only about
110 collections, and it runs in about 450 clock units. In both cases,
each collection reclaims almost all of the heap.

This looks like an obvious trading of space for time. Is this behavior
expected? Nothing in the "recent_changes" file seemed to me to
indicate that there's been a change of this nature. If this is indeed
expected behavior, is there some way to control the growth strategy
other than by tweaking the free space divisor?

I appreciate any insight you might be able to provide.


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