Re: [Pika-dev] hackerlab fsplay.[ch] status

[Andreas Rottmann]

Tom Lord <address@hidden> writes:

>     > From: Andreas Rottmann <address@hidden>
>
>     > 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
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