[Dev-luatex] luafontloader virtual access (bug #404, #448)

Paweł Jackowski P.Jackowski at gust.org.pl
Thu Sep 9 09:07:18 CEST 2010

Taco Hoekwater wrote:
> Hans and I just did some tests, and it seems that the userdata access
> is useful if *but only if* you are very low on memory. In other cases,
> it just adds extra objects to be garbage collected, which makes the
> collector slower. That is on top of extra time spent on the actual
> calls, and even worse: those extra gc objects tend to be scattered
> around in memory, resulting in extra minor page faults (cpu cache
> misses) and all that has a  noticeable  effect on run speed: the
> metatable-based access is 20-30%  slower than the old massive to_table.

Interesting. As you said, much depends on how one uses / tests. I made 
some tests with translating fontforge font structure directly into the 
luatex font table without an intermediate form. This gives bests 
results, but obviously requires too many simplifications.

> Therefore, there seems little point in expanding the metadata
> functionality any further. What is there will stay, but adding more
> metadata objects appears to be a waste of time on all sides.

OK, thank you.

Pawe/l Jackowski
P.Jackowski at gust.org.pl

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