Re: hackerlab fsplay.[ch] status
Andreas Rottmann <[email protected]> Fri, 07 May 2004 02:10:30 +0200
| Newsgroups | gmane.lisp.scheme.pika.devel |
|---|---|
| Message-ID | <[email protected]> |
Tom Lord <lord-1tv/[email protected]> writes: > > From: Andreas Rottmann <[email protected]> > > > I've started porting the GLib memchunk implementationn to > > hackerlab. > > Why? > [snip] Now that I did speed tests on alloc and free memchunks, I was not all that convinced they make sense anymore (they are noticably slower than malloc()/free()). However, I have now optimized the memchunk as not to use binary trees but bit masking and posix_memalign(3) (suggested by Owen Taylor on #gtk+) to find the area for a block, and now the speed is about the same as for malloc()/free(). > What's the case for having this facility? > Well, glibc (so I've heard) imposes a 4-byte overhead on each allocated piece of memory (it has to know the size). I thought we'd want to save that for object data areas, since hashq values might be used *very* often (additionally, with lim_malloc(), when using limits, the overhead increases by another 4 bytes). Andy -- Andreas Rottmann | [email protected] | [email protected] | [email protected] http://yi.org/rotty | GnuPG Key: http://yi.org/rotty/gpg.asc Fingerprint | DFB4 4EB4 78A4 5EEE 6219 F228 F92F CFC5 01FD 5B62 Make free software, not war!