bug#19776: 25.0.50; HTML rendering is very slow

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: monnier@iro.umontreal.ca,  stefan@marxist.se,  rms@gnu.org,
>   19776@debbugs.gnu.org
> Date: Mon, 25 Oct 2021 18:19:01 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > I guess this means timerfd is only good for when Emacs is calling
> > thread_select, i.e. either it's idling or waiting for process output.
> > So timerfd, if available, should be used together with interval
> > timers, so that we get SIGALRM when we aren't idle, I guess.  Not
> > either timerfd or interval timers, but both.
> 
> But does timerfd give us anything extra, then?  If we only use interval
> timers, things seems to work fine.  So I wonder what the purpose of
> introducing the timerfd stuff was.  Greater efficiency?  

Not sure.  Maybe more reliability?  Signals can be lost or blocked.  I
hope Dmitry will be able to answer that.