Re: distributed / parallel TeX?

[Taco Hoekwater <taco@elvenkind.com>]

Hi Lars,

Lars Huttar wrote:
> Hello,
> 
> We've been using TeX to typeset a 1200-page book, and at that size, the
> time it takes to run becomes a big issue (especially with multiple
> passes... about 8 on average). It takes us anywhere from 80 minutes on
> our fastest machine, to 9 hours on our slowest laptop.

You should not need an average of 8 runs unless your document is
ridiculously complex and I am curious what you are doing (but that
is a different issue from what you are asking).

> So the question comes up, can TeX runs take advantage of parallelized or
> distributed processing? 

No. For the most part, this is because of another requisite: for
applications to make good use of threads, they have to deal with a
problem that can be parallelized well. And generally speaking,
typesetting  does not fall in this category. A seemingly small change
on page 4 can easily affect each and every page right to the end
of the document.

About the only safe things that can be threaded is the reading of
resources (images and fonts) and, mostly because of the small gain,
nobody has been working on that that I know of.

> parallel pieces so that you could guarantee that you would get the same
> result for section B whether or not you were typesetting the whole book
> at the same time?

if you are willing to promiss yourself that all chapters will be exactly
20 pages - no more, no less - they you can split the work off into
separate job files yourself and take advantage of a whole server
farm. If you can't ...

Best wishes,
Taco
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