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author | Ævar Arnfjörð Bjarmason <avarab@gmail.com> | 2022-03-03 19:04:19 +0300 |
---|---|---|
committer | Junio C Hamano <gitster@pobox.com> | 2022-03-04 01:14:55 +0300 |
commit | 0b6d0bc9246b006ed3c241d4faace132998162d9 (patch) | |
tree | 8c55e99da40cfb725cab1f0df35b5229738c7d2d /Makefile | |
parent | a9fda017f40ee7ef2d41e52581b6064bb69ff7a2 (diff) |
Makefiles: add and use wildcard "mkdir -p" template
Add a template to do the "mkdir -p" of $(@D) (the parent dir of $@)
for us, and use it for the "make lint-docs" targets I added in
8650c6298c1 (doc lint: make "lint-docs" non-.PHONY, 2021-10-15).
As seen in 4c64fb5aad9 (Documentation/Makefile: fix lint-docs mkdir
dependency, 2021-10-26) maintaining these manual lists of parent
directory dependencies is fragile, in addition to being obviously
verbose.
I used this pattern at the time because I couldn't find another method
than "order-only" prerequisites to avoid doing a "mkdir -p $(@D)" for
every file being created, which as noted in [1] would be significantly
slower.
But as it turns out we can use this neat trick of only doing a "mkdir
-p" if the $(wildcard) macro tells us the path doesn't exist. A re-run
of a performance test similar to that noted downthread of [1] in [2]
shows that this is faster, in addition to being less verbose and more
reliable (this uses my "git-hyperfine" thin wrapper for "hyperfine"[3]):
$ git -c hyperfine.hook.setup= hyperfine -L rev HEAD~1,HEAD~0 -s 'make -C Documentation lint-docs' -p 'rm -rf Documentation/.build' 'make -C Documentation -j1 lint-docs'
Benchmark 1: make -C Documentation -j1 lint-docs' in 'HEAD~1
Time (mean ± σ): 2.914 s ± 0.062 s [User: 2.449 s, System: 0.489 s]
Range (min … max): 2.834 s … 3.020 s 10 runs
Benchmark 2: make -C Documentation -j1 lint-docs' in 'HEAD~0
Time (mean ± σ): 2.315 s ± 0.062 s [User: 1.950 s, System: 0.386 s]
Range (min … max): 2.229 s … 2.397 s 10 runs
Summary
'make -C Documentation -j1 lint-docs' in 'HEAD~0' ran
1.26 ± 0.04 times faster than 'make -C Documentation -j1 lint-docs' in 'HEAD~1'
So let's use that pattern both for the "lint-docs" target, and a few
miscellaneous other targets.
This method of creating parent directories is explicitly racy in that
we don't know if we're going to say always create a "foo" followed by
a "foo/bar" under parallelism, or skip the "foo" because we created
"foo/bar" first. In this case it doesn't matter for anything except
that we aren't guaranteed to get the same number of rules firing when
running make in parallel.
1. https://lore.kernel.org/git/211028.861r45y3pt.gmgdl@evledraar.gmail.com/
2. https://lore.kernel.org/git/211028.86o879vvtp.gmgdl@evledraar.gmail.com/
3. https://gitlab.com/avar/git-hyperfine/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'Makefile')
-rw-r--r-- | Makefile | 12 |
1 files changed, 7 insertions, 5 deletions
@@ -2745,7 +2745,8 @@ all:: $(MOFILES) endif po/build/locale/%/LC_MESSAGES/git.mo: po/%.po - $(QUIET_MSGFMT)mkdir -p $(dir $@) && $(MSGFMT) -o $@ $< + $(call mkdir_p_parent_template) + $(QUIET_MSGFMT)$(MSGFMT) -o $@ $< LIB_PERL := $(wildcard perl/Git.pm perl/Git/*.pm perl/Git/*/*.pm perl/Git/*/*/*.pm) LIB_PERL_GEN := $(patsubst perl/%.pm,perl/build/lib/%.pm,$(LIB_PERL)) @@ -2761,15 +2762,16 @@ NO_PERL_CPAN_FALLBACKS_SQ = $(subst ','\'',$(NO_PERL_CPAN_FALLBACKS)) endif perl/build/lib/%.pm: perl/%.pm GIT-PERL-DEFINES - $(QUIET_GEN)mkdir -p $(dir $@) && \ + $(call mkdir_p_parent_template) + $(QUIET_GEN) \ sed -e 's|@@LOCALEDIR@@|$(perl_localedir_SQ)|g' \ -e 's|@@NO_GETTEXT@@|$(NO_GETTEXT_SQ)|g' \ -e 's|@@NO_PERL_CPAN_FALLBACKS@@|$(NO_PERL_CPAN_FALLBACKS_SQ)|g' \ < $< > $@ perl/build/man/man3/Git.3pm: perl/Git.pm - $(QUIET_GEN)mkdir -p $(dir $@) && \ - pod2man $< $@ + $(call mkdir_p_parent_template) + $(QUIET_GEN)pod2man $< $@ $(ETAGS_TARGET): $(FOUND_SOURCE_FILES) $(QUIET_GEN)$(RM) $@+ && \ @@ -2903,7 +2905,7 @@ test_bindir_programs := $(patsubst %,bin-wrappers/%,$(BINDIR_PROGRAMS_NEED_X) $( all:: $(TEST_PROGRAMS) $(test_bindir_programs) bin-wrappers/%: wrap-for-bin.sh - @mkdir -p bin-wrappers + $(call mkdir_p_parent_template) $(QUIET_GEN)sed -e '1s|#!.*/sh|#!$(SHELL_PATH_SQ)|' \ -e 's|@@BUILD_DIR@@|$(shell pwd)|' \ -e 's|@@PROG@@|$(patsubst test-%,t/helper/test-%$(X),$(@F))$(patsubst git%,$(X),$(filter $(@F),$(BINDIR_PROGRAMS_NEED_X)))|' < $< > $@ && \ |