Re: builds are getting slower?

[Eli Zaretskii]

> From: Glenn Morris <address@hidden>
> Date: Wed, 09 Dec 2015 21:15:38 -0500
> 
> Subjectively it felt to me lately like it was taking longer to build
> Emacs than it used to. When I looked at my daily build logs, that seems
> to be confirmed - see attached figure (time for a full bootstrap).
> In particular, things seem to have gotten about 30% slower around 10th
> November. Maybe (?) this is borne out by
> http://hydra.nixos.org/job/gnu/emacs-trunk/tarball#tabs-charts
> or maybe it isn't.

Strange: the plot at Hydra doesn't seem to show any perceptible
tendency towards longer times.  If I draw an imaginary line to show
the long-term average, it stays at about the same value.  Or maybe I
misunderstand the graphs there.

I have a few questions:

  . Are these are builds from master or from emacs-25?
  . Is this reproducible? i.e., if you checkout what was HEAD on
    Nov 5, do you get bootstrap time around the values recorded
    for that date?
  . Did anything change in Hydra system configuration since the
    beginning of the year?  I mean stuff like OS upgrades, changes in
    hardware (including disk drives), new versions of GCC and Binutils
    installed.
  . (Paul already asked this.) What are the configure-time and
    make-time options? are they identical in all these builds?

I tried byte compiling large files, and I don't see more than 10%
slowdown between some build near October end and a build a few days
ago.  I measured the same 10% in optimized and non-optimized builds
(of course, absolute times are different).  So this cannot explain a
30% increase in bootstrap time, at least not on my system.  Can you
try the same experiment on Hydra?