[gclist] Using VM hardware for GC
Mark Stuart Johnstone
Sat, 24 May 1997 14:20:45 -0500
I've recently become interested in the issues involved with using an
OS's VM hardware to support generational garbage collection. I looked
over the work by Hosking, Hudson, and Moss, and they pretty much seem
to put the question to rest by pointing out that the costs of scanning
a VM page are larger than the win by using the VM hardware for the
write-barrier. They also argue that these costs will only get higher
as page size increases. However, they don't address the possibility
of the hardware providing sub-page protection.
So, what I am wondering is could a processor built with sub-page
protection (and the corresponding OS support) be more efficient than a
software only approach? If so, any guesses as to what granularity of
protection would be optimal? I realize that the frequency of
mutations has a lot to do with this issue. I am currently most
interested in Java as a target language.
Any comments or discussion would be welcome, as would any pointers to
papers on this subject that I might have missed.
E-mail: email@example.com WWW: http://www.cs.utexas.edu/users/markj
Recent papers on memory allocation and garbage collection are available by
anonymous ftp from ftp.cs.utexas.edu in /pub/garbage (See the README file).