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dad9cd7d51
This was added in 30248886ce (Makefile: disable default implicit
rules, 2010-01-26), let's move it to the top of "shared.mak" so it'll
apply to all our Makefiles.
This doesn't benefit the main Makefile at all, since it already had
the rule, but since we're including shared.mak in other Makefiles
starts to benefit them. E.g. running the 'man" target is now faster:
$ git -c hyperfine.hook.setup= hyperfine -L rev HEAD~1,HEAD~0 -s 'make -C Documentation man' 'make -C Documentation -j1 man'
Benchmark 1: make -C Documentation -j1 man' in 'HEAD~1
Time (mean ± σ): 121.7 ms ± 8.8 ms [User: 105.8 ms, System: 18.6 ms]
Range (min … max): 112.8 ms … 148.4 ms 26 runs
Benchmark 2: make -C Documentation -j1 man' in 'HEAD~0
Time (mean ± σ): 97.5 ms ± 8.0 ms [User: 80.1 ms, System: 20.1 ms]
Range (min … max): 89.8 ms … 111.8 ms 32 runs
Summary
'make -C Documentation -j1 man' in 'HEAD~0' ran
1.25 ± 0.14 times faster than 'make -C Documentation -j1 man' in 'HEAD~1'
The reason for that can be seen when comparing that run with
"--debug=a". Without this change making a target like "git-status.1"
will cause "make" to consider not only "git-status.txt", but
"git-status.txt.o", as well as numerous other implicit suffixes such
as ".c", ".cc", ".cpp" etc. See [1] for a more detailed before/after
example.
So this is causing us to omit a bunch of work we didn't need to
do. For making "git-status.1" the "--debug=a" output is reduced from
~140k lines to ~6k.
1. https://lore.kernel.org/git/220222.86bkyz875k.gmgdl@evledraar.gmail.com/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
26 lines
689 B
Makefile
26 lines
689 B
Makefile
### Remove GNU make implicit rules
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## This speeds things up since we don't need to look for and stat() a
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## "foo.c,v" every time a rule referring to "foo.c" is in play. See
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## "make -p -f/dev/null | grep ^%::'".
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%:: %,v
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%:: RCS/%,v
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%:: RCS/%
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%:: s.%
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%:: SCCS/s.%
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## Likewise delete default $(SUFFIXES). See:
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##
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## info make --index-search=.SUFFIXES
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.SUFFIXES:
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### Flags affecting all rules
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# A GNU make extension since gmake 3.72 (released in late 1994) to
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# remove the target of rules if commands in those rules fail. The
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# default is to only do that if make itself receives a signal. Affects
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# all targets, see:
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#
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# info make --index-search=.DELETE_ON_ERROR
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.DELETE_ON_ERROR:
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