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

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sun, 23 Jul 2023 22:27:26 +0300
> Cc: luangruo@yahoo.com, sbaugh@janestreet.com, yantar92@posteo.net,
>  64735@debbugs.gnu.org
> From: Dmitry Gutov <dmitry@gutov.dev>
> 
> On 23/07/2023 20:56, Eli Zaretskii wrote:
> >> And, ideally, do all the relevant benchmarking when proposing the change.
> > Of course.  Although the benchmarks until now already show quite a
> > variability.
> 
> Speaking of your MS Windows results that are unflattering to 'find', it 
> might be worth it to do a more varied comparison, to determine the 
> OS-specific bottleneck.
> 
> Off the top of my head, here are some possibilities:
> 
> 1. 'find' itself is much slower there. There is room for improvement in 
> the port.

I think it's the filesystem, not the port (which I did myself in this
case).  But I'd welcome similar tests on other Windows systems with
other ports of Find.  Just remember to measure this particular
benchmark, not just Find itself from the shell, as the times are very
different (as I reported up-thread).

> 2. The process output handling is worse.

Not sure what that means.

> 3. Something particular to the project being used for the test.

I don't think I understand this one.

> To look into the possibility #1, you can try running the same command in 
> the terminal with the output to NUL and comparing the runtime to what's 
> reported in the benchmark.

Output to the null device is a bad idea, as (AFAIR) Find is clever
enough to detect that and do nothing.  I run "find | wc" instead, and
already reported that it is much faster.

> I actually remember, from my time on MS Windows about 10 years ago, that 
> some older ports of 'find' and/or 'grep' did have performance problems, 
> but IIRC ezwinports contained the improved versions.

The ezwinports is the version I'm using here.  But maybe someone came
up with a better one: after all, I did my port many years ago (because
the native ports available back then were abysmally slow).