Re: XeConTeXt bug report I: strange benchmark

[Taco Hoekwater <taco@elvenkind.com>]

Hans Hagen wrote:
>  > 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 

For educational purposes: whether you have

   \definefont[a][file:AdobeSongLight-Std]
or
   \definefont[a][file:AdobeSongLight-Std.otf]

makes no difference to context at all.

The first makes \a expand into (simplified)

  \font\internala="[AdobeSongLight-Std]" at 12pt\internala

the second into

  \font\internala="[AdobeSongLight-Std.otf]" at 12pt\internala

but there are no other macro expansion changes at all. You can test
this yourself by making two alternative files an adding \loggingall
to them, then compare the two logs using diff.

As to the reason why one of the two is much slower than the other:
I do not know for sure, but I suspect that XeTeX does not cache
the (some of) the internals results of font file assignments with
explicit extensions. The speed difference is most certainly *not*
caused by anything the context macros do.

Best wishes,
Taco

PS As to why \definefont is itself slower than \font: it does not
actually define a font \a at a specific size. Instead it defines a
macro \a that defines and then selects a font with an internal,
temporary name, using the local font size etc.









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