Re: [PATCH 3/4] doc build: speed up "make lint-docs"

[Junio C Hamano <gitster@pobox.com>]

Ævar Arnfjörð Bjarmason  <avarab@gmail.com> writes:

> Extend the trick we use to speed up the "clean" target to also extend
> to the "lint-docs" target. See 54df87555b1 (Documentation/Makefile:
> conditionally include doc.dep, 2020-12-08) for the "clean"
> implementation.
>
> The "doc-lint" target only depends on *.txt files, so we don't need to
> generate GIT-VERSION-FILE etc. if that's all we're doing. This makes
> the "make lint-docs" target more than 2x as fast:

Nice. 0.2s down to 0.1 is a 2x speedup.

> $ git show HEAD~:Documentation/Makefile >Makefile.old
> $ hyperfine -L f ",.old" 'make -f Makefile{f} lint-docs'
> Benchmark #1: make -f Makefile lint-docs
>   Time (mean ± σ):     100.2 ms ±   1.3 ms    [User: 93.7 ms, System: 6.7 ms]
>   Range (min … max):    98.4 ms … 103.1 ms    29 runs
>
> Benchmark #2: make -f Makefile.old lint-docs
>   Time (mean ± σ):     220.0 ms ±  20.0 ms    [User: 206.0 ms, System: 18.0 ms]
>   Range (min … max):   206.6 ms … 267.5 ms    11 runs
>
> Summary
>   'make -f Makefile lint-docs' ran
>     2.19 ± 0.20 times faster than 'make -f Makefile.old lint-docs'
>
> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> ---
>  Documentation/Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/Documentation/Makefile b/Documentation/Makefile
> index 78324934d9f..e8e54e053a6 100644
> --- a/Documentation/Makefile
> +++ b/Documentation/Makefile
> @@ -284,7 +284,7 @@ install-html: html
>  ../GIT-VERSION-FILE: FORCE
>  	$(QUIET_SUBDIR0)../ $(QUIET_SUBDIR1) GIT-VERSION-FILE
>  
> -ifneq ($(MAKECMDGOALS),clean)
> +ifneq ($(filter-out lint-docs clean,$(MAKECMDGOALS)),)
>  -include ../GIT-VERSION-FILE
>  endif