Re: Major modes using `widen' is a good, even essential, programming practice.

[Stefan Monnier <monnier@iro.umontreal.ca>]

>> The more than 10x difference in performance is weird, though. Perhaps 
>> you have any ideas why parse-partial-sexp's implementation might behave 
>> poorly on your un-optimized build? Some tweak in the code might make a 
>> lot of difference.
>
> I hope Stefan could do something about it.

Not sure I can be of help.  Over the last few years we've had a few
times some significant performance regressions in the unoptimized build,
typically because of code cleanups that replace macros with inlinable
functions or things like that, where the optimized build usually doesn't
suffer (or even gets faster) which the unoptimized build can be
significantly impacted.

Way back when, an unoptimized build was not terribly slower than a -O2
build, but our current coding style in src/*.[ch] tends to make that
difference much larger.

The last few times we saw that, Paul has been quite good at finding
a few culprits and tweaking the code so that the overall impact is
brought back down to something acceptable.


        Stefan