betas

[Hans Hagen <pragma@wxs.nl>]

Hi,

As some of you might have noticed, we're in transition to luatex 0.80
(currently 0.78.1). This binary is somewhat faster with respect to nodes 
without modification of Lua code, but it also provides an additional 
node field access mechanism. Luigi and I spent quite some time on 
getting that done and in the process some 70 context files were adapted 
(as we needed to test). However, it's likely that I have missed some 
needed changes. As both access mechanisms cannot be mixed, one has to be 
consistent in usage. Also, the somewhat faster (new) usage is more 
sensitive for errors so it has to be used with robust (proven) code 
(read: pluggable code can best use the traditional node field accessors 
which also have been sped up). And of course it only makes sense for 
very demanding cases (as stock luatex is already rather efficient now), 
think of devanagari (where we can get 50% faster) and complex arabic 
(some 25%). As ConTeXt spends > 50% of its time in Lua it might make a 
difference in other places too.

Anyway, for instance the 175 fonts-mkiv manual processes 10% faster due 
to this and sometimes more can be achieved (it really depends on how 
much Lua enhanced mechanisms are used). Roughly I get on my win 8.1 64 
bit laptop for the font manual:

10    sec luatex    0.77 with previous context code base
10.25 sec luatex    0.77 with current context code base
  9.00 sec luatex    0.78 with current context code base
  7.50 sec luajittex 0.78 with current context code base

(This manual loads quite some fonts in the process.)

In case you wonder why speed is an issue: it really matters when tex is 
used as a service, and I like fast edit-test cycles too. The target is 
to get 20 pps or more even for complex documents. It's not that hard to 
get 550 pps for simple 1000 page one-word-per page documents but when 
much more kicks in we quickly drop to 15-20 pps.

Also, Luigi and I also want to reach reasonable speeds on android phones 
(triggered by Harald's experiments at the context meeting) but that's 
another topic.

Hans


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                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
     tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com
                                              | www.pragma-pod.nl
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