bug#64735: 29.0.92; find invocations are ~15x slower because of ignores

[Dmitry Gutov]

On 20/07/2023 19:03, Ihor Radchenko wrote:
> Dmitry Gutov<dmitry@gutov.dev>  writes:
>
> > > And things are not as horrible as 15x slowdown in find.
> > We haven't compared to the "optimized regexps" solution in find, though.
> Fair point.
>
> > Still like 2.5x slower, then? That's significant.
> It is, but it is workable if we try to optimize Emacs'
> `directory-files'/`file-name-all-completions' internals.
>
> > > I am pretty sure that Emacs's native file routines can be optimized to
> > > the level of find.
> > I don't know, the GNU tools are often ridiculously optimized. At least
> > certain file paths.

Sorry, I meant "code paths" here.

> You are likely right.
> Then, what about applying regexps manually, on the full file list
> returned by find?

It will almost certainly be slower in cases where several (few) ignore 
entries help drop whole big directories from traversal.