bug#8890: 23.3; message writing slows emacs

[Eli Zaretskii <eliz@gnu.org>]

> From: Dave Abrahams <dave@boostpro.com>
> Cc: larsi@gnus.org,  8890@debbugs.gnu.org
> Date: Sun, 11 Sep 2011 06:45:39 -0400
> 
> If you're just updating percentage complete, please don't do
> it more than once every .5 seconds... at the fastest!

Agreed, but that's something for the application programmers to
consider, not for the infrastructure.

> > Redisplay always slows down, but on any modern machine displaying only
> > the echo area should take a few milliseconds at the most, so I'd be
> > surprised if some real slowdown was involved.  
> 
> Don't forget that messages also fill up the *Messages* buffer.

I think that's so fast it can be ignored, unless _generating_ these
messages takes non-trivial computations.

> > Anyway, can you describe the situation in which you see these flashing
> > messages?  The only one I can think of is when Emacs starts up and
> > restores a previous session.  Is that your use case, or did you see
> > this in other situations?
> 
> Yeah, there's something in Gnus, perhaps article expiry, that seems slow
> mostly because gnus-verbose defaults to 7 and it writes out gobs of
> messages.  When I turned gnus-verbose down it seemed a lot faster.

Maybe there's something specific to Gnus, then.  In which case it's a
good thing we have Lars listening ;-)