On Sun, Jul 11, 2021 at 11:55:45AM +0100, Aaron Sloman wrote:
> Some thoughts about this issue:
<snip>
> Out of curiosity I've just tried (re-)creating clisp.psv on my machine (a year
> old), suppressing output by redirecting to /dev/null:
>
> % time mkclisp > /dev/null
> 0.405u 0.021s 0:00.43 97.6% 0+0k 0+5432io 0pf+0w
>
> On a much older machine, bought in 2011:
>
> % time mkclisp > /dev/null
> 0.458u 0.021s 0:00.48 97.9% 0+0k 0+5432io 0pf+0w
>
> In both cases the mkclisp command presupposes that the startup.psv
> saved image (invoked by running the pop11 command) already exists.
>
> Building that takes a bit longer, compiling all the main poplog
> infrastructure,
> to be run on top of the pre-built basepop11, created when Poplog is installed.
>
> Time on new machine is about a second:
>
> % time mkstartup > /dev/null
> 0.928u 0.043s 0:00.98 97.9% 0+0k 0+4280io 0pf+0w
>
> I can remember a time at sussex university in the 1980s when compiling clisp
> (on a vax or sequent symmetry or perhaps both) took about 15 minutes. Steve
> Isard may also remember such days.
>
> That's what originally provoked John Gibson (I think, or perhaps John and
> Steve
> Hardy?) to introduce use of saved images when running common lisp.
>
> That was then extended to startup of pop11 and prolog!
> (I may have misremembered some details.)
>
> My feeling is that most people who use poplog or systems built on top of
> poplog
> will typically start up then continue an interactive session for some time.
> So a
> delay of an extra second or two in starting up will typically be
> insignificant.
>
> Of course, there will be older and slower machines (with smaller amounts of
> total memory, leading to more garbage collections) on which startup time will
> be
> longer.
Classic estimate is that longer than 0.1s will be visible. User will
tolerate such delay if there is no other way, but will be much more
satisfied if startup is without delay. OTOH for glocks, logic,
eliza or probably popvision it seems that startup time is short
enough that users will not notice. So, I would say that startup
images for major subsystems are important. Also, languages are
used to write programs and such programs may be invoked from other
programs or command line. And certainly we do not want a little
utility to suffer long startup time.
--
Waldek Hebisch
