Re: performance issue with TeX Live

[Nicolas Goaziou]

Hello,

Emmanuel Beffara <manu@beffara.org> writes:

> I am facing a severe performance issue with TeX Live: compilation of any
> document is an order of magnitude slower with a Guix installed system as
> compared to a manual installation. Is anyone confronted to this phenomenon, or
> is there a way to fix this ?

I also experienced a noticeable slowdown; I don't know how to fix it yet.

> I tried doing `strace` on the pdflatex calls to investigate further and it
> appears that the behaviours of the two versions are largely different.
> Counting the number of system calls of each kind gives the following, for the
> most frequent calls:
>
> - minimal document, Guix version:
>
>    112860 newfstatat
>     10491 getdents64
>      5247 openat
>      5246 close
>      4397 access
>      3141 read
>
> - minimal document, manual version:
>
>      2772 read
>        90 openat
>        72 access
>        64 close
>        64 newfstatat
>        60 getdents64
>
> - slideshow, Guix version:
>
>   2831722 getdents64
>   1538560 newfstatat
>   1498287 access
>   1415296 openat
>   1415295 close
>      4283 read
>
> - slideshow, Guix version:
>
>      3913 read
>      1288 getdents64
>      1136 access
>       960 openat
>       925 close
>       920 newfstatat
>
> So apparently no file hash is used in the Guix version and a large part of the
> `texmf-dist` folder is browsed, probably several times.

A ls-R file is generated during profile creation (see
`texlive-font-maps' function in "guix/profiles.scm") but it seems it is
not read.

It may be interesting to compare location and contents of the ls-R files
in both installations.

Regards,
-- 
Nicolas Goaziou