Hello. Some time ago I decided to restart reading RSS feeds, but with
Gnus (liferea being really slow, not enough configurable/powerfull, and
crashing regularly (but that’s another unrelated issue)), I initially
was afraid of Gnus blocking because of the terribly unfortunate emacs
monothreaded nature and the great number of feeds I use to read…
  But that seems to be solved by the `nnrss-use-local' variable, so I
modified nnrss-generate-download-script to run multiple wget instances
asynchronously and using Tor and used the gnus-demon (which I already
use to fetch mails periodically trough a normal pop3 source) to
periodically run nnrss-download, a function updating the script and
running it asynchronously.

But now I noticed Gnus, periodically and when I hit `g' fetch feeds
manually and synchronously, blocking the whole Emacs instance… I tried
to set to nil the definition of several functions, but that were too
much ugly and I was worried it could prevent Gnus from working correctly
on some points.

(TL;DR:) Some these are my problems: I still get Gnus fetching manually
and synchronously nnrss feeds even with nnrss-use-local set to t (as
specified in Subject) and I don’t know a better way to make Gnus run
nnrss-download so that it run it at each update (i.e. even when I type
`g').

I’m on Debian GNU/Linux Sid but run a compiled-by-hand installation of
emacs 24 (emacs-version: "GNU Emacs 24.3.50.1 (x86_64-pc-linux-gnu, GTK+
Version 3.8.6) of 2014-01-23 on PC-713"). I use the Gnus version
included in Emacs of course. If I forgot relevant informations recall
me. Thanks for help.