Re: cperl + isearch + font-lock-multiline sometimes very slow

[Chong Yidong]

Klaus Zeitler <address@hidden> writes:

> Since approx. last week isearch slows sometimes down to crawling speed in
> cperl files. Looking at top I see that emacs then needs around 30% CPU and
> when I stop isearch, for the next minute emacs eats up even more CPU before
> going back to normal behavior.
> This behavior disappeared when I turned off font-lock. Therefore I checked
> my font-lock settings and found out that setting font-lock-multiline to nil
> also helped. So I'm guessing it has something to do with font-lock or
> jit-lock. How should I proceed now to investigate this further?

I can't reproduce this.  Could you provide a detailed recipe and/or
test file?

Also, see if the slowdown goes away if you increase REGEXP_CACHE_SIZE
to (e.g.) 40 in search.c, as Kim suggested.

#define REGEXP_CACHE_SIZE 20