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 the performance test I noted downthread of [1] in [2] shows that
this is faster, in addition to being less verbose and more reliable:
$ hyperfine --warmup 5 -m 30 -L s ",~" -p 'git checkout HEAD{s} -- Makefile; rm -rf .build' 'make -j8 lint-docs R={s}'
-c 'git checkout HEAD -- Makefile'
Benchmark #1: make -j8 lint-docs R=
Time (mean ± σ): 537.5 ms ± 7.1 ms [User: 2.412 s, System: 0.460 s]
Range (min … max): 530.2 ms … 564.9 ms 30 runs
Benchmark #2: make -j8 lint-docs R=~
Time (mean ± σ): 645.7 ms ± 7.1 ms [User: 3.083 s, System: 0.630 s]
Range (min … max): 637.4 ms … 675.2 ms 30 runs
Summary
'make -j8 lint-docs R=' ran
1.20 ± 0.02 times faster than 'make -j8 lint-docs R=~'
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@xxxxxxxxxxxxxxxxxxx/
2. https://lore.kernel.org/git/211028.86o879vvtp.gmgdl@xxxxxxxxxxxxxxxxxxx/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx>
---
Documentation/Makefile | 25 +++----------------------
Makefile | 12 +++++++-----
shared.mak | 7 +++++++
3 files changed, 17 insertions(+), 27 deletions(-)
diff --git a/Documentation/Makefile b/Documentation/Makefile
index 69a9af35397..d16b653394c 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -428,25 +428,11 @@ quick-install-html: require-htmlrepo
print-man1:
@for i in $(MAN1_TXT); do echo $$i; done
-## Lint: Common
-.build:
- $(QUIET)mkdir $@
-.build/lint-docs: | .build
- $(QUIET)mkdir $@
-
## Lint: gitlink
-.build/lint-docs/gitlink: | .build/lint-docs
- $(QUIET)mkdir $@
-.build/lint-docs/gitlink/howto: | .build/lint-docs/gitlink
- $(QUIET)mkdir $@
-.build/lint-docs/gitlink/config: | .build/lint-docs/gitlink
- $(QUIET)mkdir $@
LINT_DOCS_GITLINK = $(patsubst %.txt,.build/lint-docs/gitlink/%.ok,$(HOWTO_TXT) $(DOC_DEP_TXT))
-$(LINT_DOCS_GITLINK): | .build/lint-docs/gitlink
-$(LINT_DOCS_GITLINK): | .build/lint-docs/gitlink/howto
-$(LINT_DOCS_GITLINK): | .build/lint-docs/gitlink/config
$(LINT_DOCS_GITLINK): lint-gitlink.perl
$(LINT_DOCS_GITLINK): .build/lint-docs/gitlink/%.ok: %.txt
+ $(call mkdir_p_parent_template)
$(QUIET_LINT_GITLINK)$(PERL_PATH) lint-gitlink.perl \
$< \
$(HOWTO_TXT) $(DOC_DEP_TXT) \
@@ -457,23 +443,18 @@ $(LINT_DOCS_GITLINK): .build/lint-docs/gitlink/%.ok: %.txt
lint-docs-gitlink: $(LINT_DOCS_GITLINK)
## Lint: man-end-blurb
-.build/lint-docs/man-end-blurb: | .build/lint-docs
- $(QUIET)mkdir $@
LINT_DOCS_MAN_END_BLURB = $(patsubst %.txt,.build/lint-docs/man-end-blurb/%.ok,$(MAN_TXT))
-$(LINT_DOCS_MAN_END_BLURB): | .build/lint-docs/man-end-blurb
$(LINT_DOCS_MAN_END_BLURB): lint-man-end-blurb.perl
$(LINT_DOCS_MAN_END_BLURB): .build/lint-docs/man-end-blurb/%.ok: %.txt
+ $(call mkdir_p_parent_template)
$(QUIET_LINT_MANEND)$(PERL_PATH) lint-man-end-blurb.perl $< >$@
.PHONY: lint-docs-man-end-blurb
-lint-docs-man-end-blurb: $(LINT_DOCS_MAN_END_BLURB)
## Lint: man-section-order
-.build/lint-docs/man-section-order: | .build/lint-docs
- $(QUIET)mkdir $@
LINT_DOCS_MAN_SECTION_ORDER = $(patsubst %.txt,.build/lint-docs/man-section-order/%.ok,$(MAN_TXT))
-$(LINT_DOCS_MAN_SECTION_ORDER): | .build/lint-docs/man-section-order
$(LINT_DOCS_MAN_SECTION_ORDER): lint-man-section-order.perl
$(LINT_DOCS_MAN_SECTION_ORDER): .build/lint-docs/man-section-order/%.ok: %.txt
+ $(call mkdir_p_parent_template)
$(QUIET_LINT_MANSEC)$(PERL_PATH) lint-man-section-order.perl $< >$@
.PHONY: lint-docs-man-section-order
lint-docs-man-section-order: $(LINT_DOCS_MAN_SECTION_ORDER)
diff --git a/Makefile b/Makefile
index cd7727ebe39..141a87371fe 100644
--- a/Makefile
+++ b/Makefile
@@ -2622,7 +2622,8 @@ 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 $@ $<
ifndef NO_PERL
LIB_PERL := $(wildcard perl/Git.pm perl/Git/*.pm perl/Git/*/*.pm perl/Git/*/*/*.pm)
@@ -2631,7 +2632,8 @@ LIB_CPAN := $(wildcard perl/FromCPAN/*.pm perl/FromCPAN/*/*.pm)
LIB_CPAN_GEN := $(patsubst perl/%.pm,perl/build/lib/%.pm,$(LIB_CPAN))
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@@|$(NO_GETTEXT_SQ)|g' \
-e 's|@@NO_PERL_CPAN_FALLBACKS@@|$(call shq,$(NO_PERL_CPAN_FALLBACKS))|g' \
@@ -2645,8 +2647,8 @@ endif
# install-man depends on Git.3pm even with NO_PERL=Y
perl/build/man/man3/Git.3pm: perl/Git.pm
- $(QUIET_GEN)mkdir -p $(dir $@) && \
- pod2man $< $@
+ $(call mkdir_p_parent_template)
+ $(QUIET_GEN)pod2man $< $@
FIND_SOURCE_FILES = ( \
git ls-files \
@@ -2770,7 +2772,7 @@ 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)))|' < $< > $@ && \
diff --git a/shared.mak b/shared.mak
index 566eb70cf2a..ced88924ea3 100644
--- a/shared.mak
+++ b/shared.mak
@@ -73,6 +73,8 @@ ifndef V
QUIET = @
QUIET_GEN = @echo $(wspfx_sq) GEN $@;
+ QUIET_MKDIR_P_PARENT = @echo $(wspfx_sq) MKDIR -p $(@D);
+
## Used in "Makefile"
QUIET_CC = @echo $(wspfx_sq) CC $@;
QUIET_AR = @echo $(wspfx_sq) AR $@;
@@ -104,3 +106,8 @@ ifndef V
export V
endif
endif
+
+## Helpers
+define mkdir_p_parent_template
+$(if $(wildcard $(@D)),,$(QUIET_MKDIR_P_PARENT)$(shell mkdir -p $(@D)))
+endef
--
2.34.0.rc1.741.gab7bfd97031
