Subject: Re: inhibiting GC
From: Erik Naggum <>
Date: 1999/06/04
Newsgroups: comp.lang.lisp
Message-ID: <>

* Tim Bradshaw <>
| I once turned this thing on and left it turned on for several days in the
| Emacs I was using to do all my work, including several largish elisp
| packages like VM and gnus and probably psgml &c.  The results were that
| it spent about 1-2% of its time in GC, and about 60-80% in updating the
| screen.  Like Erik says, Emacs' GC is rudimentary, but it was so far from
| the critical path in terms of performance as to be totally irrelevant.
| So much for mythology.

  there are several interesting aspects to this: (1) people see that
  something is happening when the screen updates, (2) people see a pause
  when the "Garbage collecting..." message lights up, and (3) they thought
  Emacs got a lot faster when that message was removed (at my request).

  if it moves slowly, humans can deal well with it.  if it moves in jerks
  and spasms, humans get nervous.  the overall impression of "smoothness"
  is very important to user perception of speed; any break in smoothness is
  then taken as a serious flaw.  we see the same thing in many areas:
  people had no problems dealing with 110 baud ttys 20 years ago, and if
  the information trickles in, people can still deal with very slow lines
  (witness the World Wide Wait, and how people happily wait for images of
  text to crawl across the line at the rate of 1 character a second), but
  if you give somebody a 56kbps line and it goes from 56 kbps to 110 bps
  and back at random intervals, you can drive people literally insane, and
  that's precisely what the WWW does to congested links.  still, it's the
  greatest thing since sliced bread.  all we have to do now is make the WWW
  better than sex for the dumb people who click on the advertising, so they
  won't procreate!  ahem, I digress.

@1999-07-22T00:37:33Z -- pi billion seconds since the turn of the century