Bug#750785: Slowness with context and xetex

[Khaled Hosny <khaledhosny@eglug.org>]

On Tue, Aug 05, 2014 at 03:04:03PM +0900, Norbert Preining wrote:
> Hi Khaled,
> 
> concerning the slowness in xelatex and context/xetex, I found now
> which call is so delaying. I interspersed lots of printf and found that
> most time the xelatex process is stucked in the following line
> from XeTeXLayoutInterface.cpp:
> 	shape_plan = hb_shape_plan_create_cached(hbFace, &segment_props, engine->features, engine->nFeatures, engine->ShaperList);
> 
> Does this tell you *anything*? In Debian we are running with harfbuzz
> 0.9.33 at the moment, and I also checked the sources, there is only
> one completely unrelated patch that Debian adds.
> 
> The whole output is mostly stucked in function layoutChars, where the
> above call happens.
> 
> Do you have any idea where the slowness could come from? It seems -
> only from reading the name of the function - that maybe something
> is not proberly cached?

I don't really know, may be Behdad have some suggestions.

Regards,
Khaled