[Tex/LaTex] Why XeLateX is slower than pdfLaTex, and some times has a long pause before running the main file

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My question is very straightforward, Why XeLateX is slower than pdfLaTex, and some times has a long pause before running the main file?

I know XeTeX/XeLaTeX has to load a lot of packages, but why, once a while, it stops for a long time after the last file loaded?

and further more why after starting to compile the pages, the average speed of XeTeX's page processing is slower than the average speed of pdfTeX's page processing?

Best Answer

xetex is an extension of TeX, not pdflatex, so after xetex has run it needs to run a separate dvi driver program to convert the generated dvi file (extended dvi known as xdv) to postscript. By default this driver (xdvipdfmx) is called automatically, but on large documents it may account for a noticeable pause after the final tex message on the terminal.

The above accounts for any "final pause", but otherwise xetex is in general slower than pdftex (and faster than luatex) they are different systems working with different font technologies and different character data structures, so you would expect some differences.

Related Solutions

[Tex/LaTex] How to force xelatex to convert eps into pdf? speed issue with slow compilation of xelatex

Why don't you simply call once epstopdf file.eps to convert your eps before running xelatex?

Beside this: Converting the file on the fly when it doesn't exist is not so difficult. E.g. compile this with xelatex --shell-escape:

\documentclass{article}
\usepackage{graphicx}
\begin{document}
\IfFileExists{testeps1.pdf}{}{\immediate\write18{epstopdf testeps1.eps}}
\includegraphics{testeps1}
\end{document}

But epstopdf doesn't convert only when the file doesn't exist but also compares file dates and updates the file if the eps has been changed and this is more difficult to implement in xelatex as some of the primitives used seem not to exist. So when you change the eps you must ensure that you trigger the conversion again.

[Tex/LaTex] XeLaTeX runs slow on Windows machine

I've been wrestling with the same issue too after upgrading TeXLive from 2013 to 2016. Each compilation started to take over a minute and the process monitor showed a lot of font files being read.

Running fc-cache.exe from the LaTeX distribution's bin folder (as indicated by the comment above) fixed the issue without reinstalling TeXLive.

Please note that the distribution's texmf-var\fonts\cache folder needs to be writeable to the user running fc-cache.exe.

Best Answer

Related Solutions

[Tex/LaTex] How to force xelatex to convert eps into pdf? speed issue with slow compilation of xelatex

[Tex/LaTex] XeLaTeX runs slow on Windows machine

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