[R] resetting the interpreter

[Prof Brian Ripley]

On Fri, 23 Apr 2004, Richard A. O'Keefe wrote:

> Gabor Grothendieck <ggrothendieck at myway.com> wrote:
> 	If you haven't tried 1.9.0 yet it does start up faster than 1.8.1.
> 	
> For what it's worth, on my SunBlade 100,
> R 1.7.1 started in 4 seconds of CPU time, 25 seconds of wall-clock time
> R 1.9.0 starts  in 3 seconds of CPU time, 20 seconds of wall-clock time.
> 
> I measured the time by doing
> 	% time R
> 	> quit("no")

Better to do

	% time R --vanilla < /dev/null

That does seem a rather slow machine: our Sun server manages it in 1.0.

> It's really good to see *any* improvement in startup time, and I must
> thank the R developers for even *trying* to do anything about it.  There's
> some way to go yet; octave starts in under a second.

It is documented in the NEWS file:

    o	There has been a concerted effort to speed up the startup of
	an R session: it now takes about 2/3rds of the time of 1.8.1.

and BTW without those efforts it would have been 1.5x the time of 1.8.1.

If you want a much greater increase, remove `methods' from the list of 
default packages as it is responsible for about half the current startup 
time.  And if you want a really fast startup with minimal facilities, use 
no default packages.

On my office desktop (RH8.0, Athlon MP2600):

time R --vanilla < /dev/null
0.873u 0.035s 0:00.91 98.9%     0+0k 0+0io 1098pf+0w

setenv R_DEFAULT_PACKAGES "utils,graphics,stats"
time R --vanilla < /dev/null
0.505u 0.041s 0:00.55 98.1%     0+0k 0+0io 1090pf+0w

setenv R_DEFAULT_PACKAGES NULL
time R --vanilla < /dev/null
0.099u 0.017s 0:00.11 90.9%     0+0k 0+0io 1033pf+0w

There are planned improvements (hopefully for 2.0.0 next October) which 
will load objects on first use and so about halve the second of these 
times.


-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595