Re: [PATCH v2 00/10] Makefile: make generate-cmdlist.sh much faster

From: Jeff King <peff@peff.net>
Date: Oct 25, 2021, 16:57 UTC
Message-ID: <YXbh+YR19bygRFaX@coredump.intra.peff.net>
In-Reply-To: <cover-v2-00.10-00000000000-20211022T193027Z-avarab@gmail.com>

On Fri, Oct 22, 2021 at 09:36:04PM +0200, Ævar Arnfjörð Bjarmason wrote:

Show 11 quoted lines

> This version of this series drops the Makefile-powered version of the
> cmdlist in favor of making the shellscript much faster, mostly with
> suggestions from Jeff King.
> 
> I still think that splitting out the generated data into files may be
> useful for unifying the Documentation/ and C code build processes,
> there's another custom parser for command-list.txt in
> Documentation/cmd-list.perl.
> 
> But if and when I've got something for that I can dig that out of the
> v1, in the meantime the v1 of this should be mostly uncontroversial.

Thanks, up through patch 8 this all looks good to me.

> The last tow patches make things a bit slower for me, but since they
> replace command invocations with pure-shell logic they presumably make
> things a bit less painful on e.g. Windows, and the 8th patch here
> already made things quite very fast already.

These ones I could take or leave. They probably do help a little on Windows, but I'm much more concerned about O(nr_of_commands) process invocations than I am in reducing the base number of invocations (because one gives a 169x speedup over the other).

And in patch 9 in particular, we're trading a grep one-liner for a much-longer shell loop. And I don't think this is hypocritical with respect to patch 8; there we are replacing ugly sed with ugly shell, and the speed benefit is clear and large.

-Peff