[ESS] Aquamacs ESS slow scroll (buffering?)

[Vitalie Spinu]

 >>> Martin Maechler on Mon, 25 Nov 2013 09:13:21 +0100 wrote:

 > I've seen similar "slowdown on humongous output" behavior in ESS on Linux.
 > (and it may have worsened recently)... but then I've always had the feeling that
 > this should teach users to prefer str(.) for potentially large objects.. :-)

Or C-c C-d C-e C-e ... 

 > I agree it woul be nice if we (ESS) could do much better than now.
 > Vitalie, do I understand correctly that your optimization only applies
 > when font locking has been turned off ?

No, it applies to font lock as well, but it is insignificant when
font-lock is on. 

On this issue, several things inter-play: font-lock, machine
performance, emacs re-display and the amount of text already present in
the process buffer. I sort of solved the last issue.

One workaround that could be implemented is to hide the long input with
elipses. The elipses could be expanded on user's request. Then nor emacs
redisplay, nor font-lock will interfere.

  Vitalie

 > On Mon, Nov 25, 2013 at 2:01 AM, Vitalie Spinu <spinuvit at gmail.com> wrote:
 >> 
 >> Hi Paul,
 >> 
 >> I have just added an optimization. It should be considerably faster if
 >> you don't use font lock, especially if you already have long comint
 >> buffer.
 >> 
 >> The main issue is font-lock for me. It drags your example from 9 sec to
 >> unbelievable 500 seconds on my machine. I don't know how to satisfactory
 >> address this. Some time ago I tried to tinker with it by deactivating
 >> during the process output, but nothing came out of it.
 >> 
 >> Vitalie
 >> 
 >> 
 >> >>> Paul Johnson on Sun, 24 Nov 2013 14:06:37 -0600 wrote:
 >> 
 >> > I've been uninterested in Macs, but I'm trying to be more helpful with
 >> > student questions by using a MacBook Pro sometimes.  I installed Aquamacs,
 >> > which has ESS 13.05 built in.
 >> 
 >> > I'm encouraging students to Aquamacs because there is some hope of
 >> > continuity across platforms if they learn Emacs on Windows and Linux.  But
 >> > it is not as uniform as I would like, since Aquamacs has fiddled the menus
 >> > and shortcut keys just enough to make this frustrating. Anyway...
 >> 
 >> > Yesterday, a student said he preferred to use R.app because Aquamacs is
 >> > super slow while displaying long vectors of text values. Huh? I thought he
 >> > must have broken something in his Mac, but I see same.
 >> 
 >> > Can you guess if this is a configuration problem, or a Mac OSX problem?
 >> 
 >> > My working example, with system.time output at the end.
 >> 
 >> > ## Paul Johnson
 >> > ## 2013-11-23
 >> 
 >> > ## Student reports that Macintosh Aquamacs has slow on-screen scrolling
 >> > ## of large text arrays. So I've created this test
 >> 
 >> > set.seed(23456)
 >> 
 >> > y <-  lapply(1:50000, function(x) paste0(letters[1:(rpois(1, 10))],
 >> > collapse=""))
 >> 
 >> > system.time(print(y))
 >> 
 >> > ## Aquamacs output (ESS 13.05)
 >> > ## user  system elapsed
 >> > ##  0.293   0.268  88.735
 >> 
 >> > ## R.app output
 >> > ## user  system elapsed
 >> > ##  1.552   0.028   1.575
 >> 
 >> > Why is elapsed time so grossly in excess of user + system.
 >> 
 >> > This reminded me of the problem in MS Command Shell when running C programs
 >> > compiled with gcc (back in the day). Viewing lots of printf statements was
 >> > very slow in Windows, not in Linux.
 >> 
 >> >> sessionInfo()
 >> > R version 3.0.2 (2013-09-25)
 >> > Platform: x86_64-apple-darwin10.8.0 (64-bit)
 >> 
 >> > locale:
 >> > [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
 >> 
 >> > attached base packages:
 >> > [1] stats     graphics  grDevices utils     datasets  methods   base
 >> 
 >> > I don't know how to describe the Aquamacs version to you. The file it comes
 >> > from is on http://aquamacs.org:Aquamacs-Emacs-2.5.dmg>  > In there I find:
 >> > ESS- 13.05
 >> 
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