Re: Lua 5.1 (work4) now available

[Roberto Ierusalimschy <roberto@...>]

> There's one outstanding GC issue which bothers me a bit: my
> app's typical in-use mem figure (collectgarbage("count")) at
> any given time is still approximately twice as large as it
> 'should' be.  I deduce this by performing a few 'full' GCs
> in a row at random times and noticing that the in-use mem figure
> drops to around 2500K rather than its usual 4400-4900K
> range (though in several seconds it climbs back up into this
> range).

That is strange, but not too strange. With the previous GC, mem figures
would grow from a minimum (just after a collection) to twice that
minimum, when a new collection was triggered. With an incremental
collector, we do not have that flutuation. But it seems that the maximum
memory used by both collectors would be more or less the same.


> Attached is a patch which tunes the new default GC tuneables
> in accordance with my experiments in perf/peakmem tradeoff.

Do you have any explanation why those numbers are better?

-- Roberto