Re: Question about Lua 5.1.3 and realloc() on life.lua

[Ralph Hempel <rhempel@...>]

Bogdan Marinescu wrote:

> Fortunately,
> dlmalloc is what Newlib uses, so at least ARM platforms are OK, since
> all the ARM embedded toolchains I know use Newlib. And yes,
> percentages are good :)

I've written a stripped down best-fit malloc that is very fast on
ARM7 devices with very limited RAM. I still get fragmentation on
the order of 20-30%.

The typical use of pbLua on LEGO MINDSTORMS NXT is in console mode, so
there's a lot of messing around with relatively short strings.

I did review dlmalloc() but decided (perhaps foolishly) that it
was too much code for what I was doing. No doubt it works in
a lot of different environments, but all those switches ended up
intimidating me.

The binning of chunks is a great idea when you need to find a free
block. My allocator does free block coalescing whenever possible
but I should really look at using up older chunks first, like dlmalloc
does.

Sorry for the rambling post, but it's clear that deciding which
malloc to use has a lot of tradeoffs. Having written my own
allocator and spent more time testing and debugging than I ever thought
possible, I can highly recommend picking one that you know works. :-)

Worry about tuning if it's a real problem.

Ralph