Re: Speed of rc

[haahr@mv.us.adobe.com (Paul Haahr)]

> When running commands or scripts it seems that rc often takes longer
> than it should, especially compared to sh or ksh.

i don't find this true at all.  i haven't ever used ksh seriously, but
rc feels (that's not is, but feels) much faster than sh on all machines
i've tried it on.

> I also seem to
> remember seeing something in comp.unix.shell within the last couple of
> months, about the relative speed of various shells, which showed rc as
> being substantially slower.

i don't remember it that way.  as i recall, the numbers from rc looked
about the same as all other shells, which was not surprising, given that
the benchmark seemed to be testing just how fast the machine forked.

> What this leads me to wonder is, if anyone
> has ever bothered to do any serious timing tests or profile rc and find
> out where it's spending its time?

i know that Byron had done this on at least several times during his work
on rc, but i don't think he's done it recently.  the last major performance
tweak that i recall was that there were some list operations being done
in O(n^2) time when they didn't have to be, and that fixed, but i'm not
sure if that was a pre- or post-1.4 change.

profiling code & looking for hot spots is always a good thing to do.
i think you'll find that rc is pretty much flat and not spending an
inordinate amount of time in any particular kind of operation.

paul