Re: Performance on NFS

[Roel Janssen <roel@gnu.org>]

Ludovic Courtès writes:

> How does:
>
>   time guix environment --ad-hoc coreutils --pure -- true
>
> compare to:
>
>   time guix environment --ad-hoc -e '(@ (gnu packages base) coreutils)' --pure -- true
>
> ?  That would give us an estimate of how much the cache I describe would
> help.
>
> Thanks,
> Ludo’.

You should know that we have 'submit' nodes that use the guixr wrapper
script to connect to the guix-daemon that runs on the 'hpcguix' node.

Both have a /gnu mounted by a storage subsystem.

I couldn't run the second command on a 'submit' node.  But I could run
it in the 'hpcguix' node.


The first command:
------------------

[roel@hpc-submit1 ~]$ time guixr environment --ad-hoc coreutils --pure -- true

real    0m38.415s
user    0m6.075s
sys     0m0.611s

[roel@hpcguix ~]$ time guix environment --ad-hoc coreutils --pure -- true

real    0m27.054s
user    0m4.254s
sys     0m0.383s


The second command:
-------------------

[roel@hpcguix ~]$ time guix environment --ad-hoc -e '(@ (gnu packages base) coreutils)' --pure --no-substitutes --no-grafts -- true                                                                                                      
The following derivations will be built:
   /gnu/store/9wczighnyz1bz43j4wawf09z180g3ywv-profile.drv
   /gnu/store/ffsyhajbdcp1lcq6x65czghya1iydly8-info-dir.drv
   /gnu/store/5gyl3l23ps6f8dgay4awybwq7n9j9pzk-fonts-dir.drv
   /gnu/store/l2mwj2q4vnq2v5raxz64ra7jyphd2jyd-manual-database.drv
Creating manual page database for 1 packages... done in 5.524 s

real    1m6.812s
user    0m2.969s
sys     0m0.325s
[roel@hpcguix ~]$ time guix environment --ad-hoc -e '(@ (gnu packages base) coreutils)' --pure --no-substitutes --no-grafts -- true

real    0m23.357s
user    0m2.802s
sys     0m0.340s


I suspect that the difference between the two commands is that one only
looks for one module, while the other looks in all modules.  Looking at
the second run, I suppose the difference is quite small.

Kind regards,
Roel Janssen