bug#58558: 29.0.50; re-search-forward is slow in some buffers

[Ihor Radchenko]

Mattias Engdegård <mattias.engdegard@gmail.com> writes:

> Ihor, would you consider the possibility of regexp cache thrashing? It does 
> occur from time to time; that cache is quite small. Try this instrumentation 
> patch. (We should probably have something like it permanently.)

Generating agenda with Emacs master + your patch:

 :regexp-cache-hit: 6225399 :regexp-cache-miss: 109490

Emacs 28.3 + your patch:
 :regexp-cache-hit: 4968571 :regexp-cache-miss: 79637

Also, I tried to play around with increasing REGEXP_CACHE_SIZE in the
past. It does not make noticeable difference in my setup.

-- 
Ihor Radchenko // yantar92,
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