bug#44053: ‘xdg-mime-database’ profile hook is slow

[Luis Felipe]

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Friday, November 6, 2020 9:10 AM, Ludovic Courtès <ludo@gnu.org> wrote:

> Hi,
>
> Luis Felipe luis.felipe.la@protonmail.com skribis:
>
> > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
> > On Tuesday, November 3, 2020 11:32 PM, zimoun zimon.toutoune@gmail.com 
> > wrote:
> >
> > > Hi,
> > >
> > > > https://git.savannah.gnu.org/cgit/guix.git/commit/?id=76ea70bd70aeb76570445c11cea2f98139192b54
> > >
> > > Clever workaround! What are now the performances on previous examples
> > > (same profiles and same packages)?
> >
> > In my case there seem to be no improvement (using Guix 
> > 5e7cf66fb35780f930ad0bc5fe21ac330df4411d).
>
> Please note that the change above addresses only one specific source of
> slowness, the ‘xdg-mime-database’ hook, and only in specific cases.
>
> It’s good to look at the overall timing of ‘guix install’, because
> that’s what matters in the end, but as we work on optimizing it, we have
> to look at specific aspects of it.
>
> > $ time guix package -i perl --max-jobs=1


Yeah, sorry I was more focused on the general issue (#44053), but I understand.


> [...]
>
> > injertando 12 paquetes en 
> > /gnu/store/anknpdyhmfirw3rz2k9zm9kiyak8yy1s-cups-filters-1.27.4.drv ...
> > construyendo la base de datos MIME XDG...
> > injertando 3 paquetes en 
> > /gnu/store/xgny7xbl635g8na8x03x4cdr7abiphiw-cups-2.3.3.drv ...
> > injertando 20 paquetes en 
> > /gnu/store/yhjl68x7kcjbv40v823x4hl8rvv8l50b-gtk+-2.24.32.drv ...
> > injertando 21 paquetes en 
> > /gnu/store/kq37fnw8335f1hqc3j4hhqqcdnhl371p-gtk+-3.24.20.drv ...
> > creando la caché de temas de iconos de GTK+...
> > construyendo los ficheros de caché para los métodos de entrada de GTK+...
> > construyendo perfil con 86 paquetes...
> > real 8m38,121s
> > user 0m2,742s
> > sys 0m0,338s
>
> Here it’s likely that grafting is what’s taking the most time on a
> spinning disk.

It does take some time, but since I can see the output change from grafting to 
grafting, I at least can tell guix is doing something, so I just let it be.

Compared to grafting, the last step "construyendo perfil con X paquetes..." 
("building profile with X packages..."), just stays there without change for 
several minutes, so it actually seems slower to me. Initially, I thought that 
guix had frozen.

Also, even though, the "building profile" step has a throbber (| / - \) to 
indicate that something is being done, it frequently stops in one of the frames 
of the sequence and stays there until the end.


> We should hack (guix status) so it can optionally prefix each event with
> a timestamp.
>
> As far as ‘xdg-mime-database’ is concerned, it should be down to 0s,
> unless your profile contains one of the packages I cited (libreoffice,
> gcr, hugin, etc.).

Yes, I have Libreoffice installed.