Re: [Texmacs-dev] Disastrous boot time for new versions

[david]

On Wed, Mar 05, 2003 at 09:32:23AM +0100, Joris van der Hoeven wrote:
> Nevertheless, the increase in boot time scares me,
> because we want to move much of the top level interface to Guile.
> So even if I postpone whatever possible, this will still leave
> us with a lot of code to be executed. So we might have to consider
> your idea at some point. Maybe it would also be possible to
> let guile create a dump of all (or a selection of) variables
> which have been declared at a given point and save this in a file.
> This would remove drawback 1.

I think we should not forget that GUILE is a language for _extension_.
Not a language for application development. For example, it is fully
interpreted. In that respect, I think that TeXmacs is actually
_abusing_ GUILE.

That is not a philosophical problem to me. But the more texmacs will
use GUILE as a application language (instead of a mere extension
language) the more it will make sense to use a more efficient
implementation of Scheme.


> A slightly different point: I also noticed that TeXmacs takes
> a lot of  time to boot after a reboot of the computer.
> Subsequent runs are much faster. Now I know that applications
> are being cached, but still: TeXmacs takes a comparatively long
> time to boot with respect to programs of a similar size.
> Someone has an idea about that?

Disclaimer: I am not a system programmer.

One thing that can take up a lot of kernel and i/o time is loading
many small files. For example, on my system (using ext3 on kernel
2.4.20), when compiling the user manual, I see that about half the CPU
time is spent in the kernel. Maybe opening and closing many files may
hit some bottlenecks in the filesystem implementation.

Also, reading many files may defeat read-buffering. Once TeXmacs has
been loaded once (and assuming there is enough free RAM), the loaded
files are cached. That does not prevent hitting filesystem
bottlenecks, but that definitely prevent from waiting for drive seeks.

TeXmacs already has an caching system for style files. Maybe it would
help to implement such a caching for scheme files, encoding files,
etc.