> Taco Hoekwater wrote:
Hans Hagen wrote:
anyway .. i cannot comment on runtimes as xetex on my windows box runs
too slow (caching issue) and all examples are slow, no matter how i
specify fonts so i will not look into the code till that gets fixed first
The example with the typescript seems logical to me: a typescript does
much work beforehand, so I assume SimSum is loaded multiple times.
I am trying the AdobeSong example as we speak, there surely seems
something wrong there.
let's start with saying that I have no intention to optimize mkii for
xetex as we decided some time ago (at the context meeting) that we would
freeze mkii; so, if things run acceptable that's ok for me; we're also
not going to optimize any further for pdftex any more unless i need it
in a high performance project -)
when i delete my font.conf file (i.e. forget about names but only allow
files) i can run xetex with reasonable performance
some timing:
% 64 sec xetex, 11 sec luatex (56 sec xetex when \nobigmath)
\setupbodyfont[myzhfont]
\dorecurse{10000}{{hello {\switchtobodyfont[myzhfont] 你好}}\par}
% 67 sec xetex, 11.5 sec luatex
\dorecurse{10000}{{hello {\switchtobodyfont[myzhfont] 你好}}\par}
% 5 sec xetex, 7 sec luatex
\setupbodyfont[myzhfont] \dorecurse{10000}{{hello {你好}}\par}
now, in practice one will not switch complete bodyfonts so often, so
something like
\setupbodyfont[myzhfont] \dorecurse{10000}{{\bf hello {你好}}\par}
is more realistic (taks .5 sec more in xetex)
as taco mentioned, switchtobidyfont does way more than just switching a
font like checking current state which involves checking fontclass,
size, style etc and setting up font parameters for each case, as well as
setting up math; fonts, when not yet set, will be loaded but that
happens only once so that can be kind of neglected
the differences between mkii and mkiv have several reasons:
= mkiv has a more efficient font system as no encodings, mappings, one
math family etc are involved and as such is much faster (less comma list
processing, less checking, less mapping and encoding switches)
= in mkii there is a relationship between fonts, languages etc an dall
need to be (re)synced since anything can have changed; i'm pretty sure
that context does much more here than latex because we cater for mixed
typefaces, mixed languages, encodings, etc and all combinations that can
occur
= mkiv code has been optimized in the process so that might also count a
bit (but not that much in real situations)
= mkiv can use traditional traditional fonts but does that in a special
way by turning then into wide fonts which is also more efficient
now, since xetex runs on top of mkii it caries some overhead from
traditional fonts
if we accept some limitations (i.e. stupify context mkii a bit) we can
gain some speed (we can probably also load some less code then), for example
\def\updatefontparameters
{\edef\@@fontfeatures{\truefontdata\fontfile\s!features}%
\edef\@@fontskewchar{\truefontdata\fontfile\s!skewchar}}
\def\setfontcharacteristics
{\updatefontparameters
\the\everyfont}
\let\synchronizepatternswithfont\relax
saves 20 sec on the 10K (irrealistic anyway) run but then we definitely
need to make typescripts xetex specific and make sure that no encoded
font files are used any longer
The question is ... does it pay off for me (as i have to do it in order
to make sure we don't mess up things for pdftex) to spend time on this?
Probably not.
(Concerning timing: forget about comparing to latex as in practice much
more is involved like page building etc. There are subsystems in context
where i could squeeze out yet another .1 second just to see it become
noise on real runs.)
Hans
-----------------------------------------------------------------
Hans Hagen | PRAGMA ADE
Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
tel: 038 477 53 69 | fax: 038 477 53 74 | www.pragma-ade.com
| www.pragma-pod.nl
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