[XeTeX] xetex memory usage

basketboy at bk.ru basketboy at bk.ru
Wed Dec 17 00:36:51 CET 2008

Jonathan Kew пишет:
> On 16 Dec 2008, at 19:53, basketboy at bk.ru wrote:
>> Hello,
>> I'm using MiKTeX 2.7 and xetex(xelatex) integrated in it. OS:  
>> Windows XP
>> SP3.
>> My question is about memory usage of xetex. I've noticed that when I
>> compile tex document, though this:
>> \documentclass{article}
>> \usepackage{fontspec}
>> \setmainfont{Arial}
>> \begin{document}
>> The quick brown fox jumps over the lazy dog.
>> \textbf{The quick brown fox jumps over the lazy dog.}
>> \emph{The quick brown fox jumps over the lazy dog.}
>> \end{document}
>> I see that it uses at least 130MB of RAM to generate pdf. So if for
>> example I'm going to use xetex to generate pdf reports via webpage it
>> can cause memory overusage. For example if 10 people start to generate
>> pdfs simultaneously then 1300Mb of RAM will be used and it can cause  
>> the
>> problems. We run into this problem already (with much more complex tex
>> documents) and server with 512 MB of RAM and it was overloaded.
>> So my questions are the following:
>> 1. Is this problem related with xetex or maybe fonts loading into
>> memory? If it is not related to xetex then sorry, I'll try to find
>> answer from MiKTeX users.
> The RAM footprint is much larger than standard 8-bit TeX because many  
> internal tables have been expanded to cover the full Unicode range of  
> characters -- approximately one million, as compared to 256  
> characters. Using over 100MB is not generally a problem on modern  
> hardware; much of this memory is not actively used in a typical run,  
> and so virtual memory systems need not even keep it in real RAM, but  
> it does get allocated at startup.

Thanks a lot for explanation.
>> 2. Is it possilbe to reduce RAM consumption in this case?
> Not with the existing program. Many of the internal arrays could be  
> made much smaller by using a smarter "sparse array" implementation  
> instead of simple flat arrays. This has not been a priority for me, as  
> users do not normally need to run large numbers of xetex processes in  
> parallel, but if someone wants to provide such a patch it would be  
> welcome.
> Actually, you could reduce the RAM footprint quite a bit by reducing  
> various parameters in texmf.cnf (for TeX Live; I don't know if MikTeX  
> uses a similar configuration file), as the default settings (at least  
> with TL) are extremely generous, and most documents can be processed  
> within much smaller limits.

Hmm. Intersting. Can you please suggest some parameters for example in 
texmf.cnf which can reduce RAM footprint?

> JK
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