[Tex/LaTex] pdflatex – how to find bottleneck of long compiling time for the document

compilingpdftex

I'm having (again/still) a very large LateX document which I'm working on.

>340 pages
many graphics (mostly included pdf, but also some PNG or others)
many tables (also longtables)
resulting PDF is >18 MB in size
many references and citations

Compilation takes between 2 and 7 minutes normally. I'm using latexmk for complete compiling, so the given times normally is for several latex runs in total.

Nevertheless I'd like to speed up the process of recompiling and try to find the bottlenecks. When I see the console output, it seems to hang at some points where compiling takes longer.

Is there a way to analyze which steps takes how much time and thus find those 20% of the things which might cause 80% of the compiling time?

E. g. can I print the duration it takes to process each page and so see which pages take the most time to build?

Pareto rules:

Thanks to @Robert 's answer, I now have the compiling times of each page and

indeed it is about 20 pages of the 340 which take more than 50% of the compiling time!
2 pages even need about 20 s for compiling!
none of those "slow pages" seems to include PNG images

Very strange, I'll have to dig deeper – maybe cross references or fixme remarks are the problem?!

Best Answer

You could build your timer with \pdfelapsedtime:

\usepackage{atbegshi}
\newcommand\showtimer{%
  \message{^^Jtimer: \the\numexpr\the\pdfelapsedtime*1000/65536\relax}%
  \pdfresettimer}
\AtBeginDocument{\showtimer}
\AtBeginShipout {\showtimer}

would print the time it took (in milliseconds) for each page to be output (here p. 231 took 103ms, p. 232 took 44ms):

timer: 103 [231] 
timer: 44 [232]

Note that due to the asynchronous nature of tex's output routine, this isn't completely exact: firstly, the page breaker usually only kicks in after a paragraph break, so that material that will actually end up on the next page (or even pages for very long paragraphs) has already been processed; secondly, inserts (floats, footnotes) may have been processed already earlier -- for example, split footnotes or floats that didn't fit on the previous page(s). So the numbers may actually measure the processing time both of material from previous and from later pages.

For evaluation you can extract those lines:

grep '^timer:' filename.log > Compiletime.txt

Related Solutions

[Tex/LaTex] How to speed up pdflatex for a very large document on MacOS X

Take a look this description. It's a description of how to format the preamble yourself. Assuming your source file is main.tex, it all comes down to these steps (which were copied from the link and modified by me for my own use):

Rearrange your preamble so that its static part precedes any dynamic part. What in the preamble can be “dynamic”? For example, if you use \includeonly, you probably want to change its argument rather frequently and so it is not static. Finally, some packages read and write auxiliary files when you issue a command that you should put in the preamble (eg, nomencl uses `\makenomenclature). Clearly, you have to run these commands in every run.
Extract the static part of the preamble into, say, preamble.tex. At this point, main.tex no longer contains the static part. It should start with the dynamic part, or simply `\begin{document} if you have nothing dynamic.

Execute:

pdflatex -ini -jobname="preamble" "&pdflatex preamble.tex\dump"

in the command line. You will notice that a new file `preamble.fmt has been generated in the same directory, along with other auxiliary files.

Edit the first line of main.tex so that it starts with %&preamble.
Execute latex main.tex as usual:
```
pdflatex -shell-escape main.tex
```

You may get an error about the class file immediately, or you may notice that latex finishes as usual. But if you have paid attention to the output, or if you inspect the the log file, then you will see that the preamble gets processed in “no time” at all. At this point, cheers!

To make things slightly fancier, here is an modification. First, add this to the end of preamble.tex:

\def\preambleloaded{Precompiled preamble loaded.}

Then, before the dynamic preamble (or \begin{document} if there is none) of `main.tex, add:

\def\ifundefined#1{\expandafter\ifx\csname#1\endcsname\relax} \ifundefined{preambleloaded}
\typeout{PRECOMILED PREAMBLE NOT LOADED}\input{preamble} \else
\typeout{\preambleloaded}
\fi

The idea is to define a macro in the precompiled preamble and use it to detect if the precompiled preamble has been loaded or not. If not, \input{preamble} will be used to pull the static preamble back in and you will not see any error at all.

Also, if you are using tikz to make figures, have a look at the external library. Check the Tikz and Pgf manual, section 32 describes how to use it.

[Tex/LaTex] way to find out how long it took for the document to compile

This is somewhat OS dependent. On Linux and OS X you can use the time command from the command line.

time pdflatex myfile.tex

returns: (e.g.)

real    0m1.976s
user    0m0.331s
sys     0m0.091s

There may be a similar command in Windows. Depending on your editing environment, you can probably modify the latex command from within the editor (temporarily) to run the time command when you compile, which would make checking the times for different package configurations easier.

Best Answer

Related Solutions

[Tex/LaTex] How to speed up pdflatex for a very large document on MacOS X

[Tex/LaTex] way to find out how long it took for the document to compile

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