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tools/perf/build: Speed up the final link

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libtraceevent.a and liblk.a rules have always-missed dependencies,
which causes python.so to be relinked at every build attempt - even
if none of the affected code changes.

This slows down re-builds unnecessarily, by adding more than a second
to the build time:

  comet:~/tip/tools/perf> time make

  ...

    SUBDIR /fast/mingo/tip/tools/lib/lk/
    make[1]: `liblk.a' is up to date.
    SUBDIR /fast/mingo/tip/tools/lib/traceevent/
    LINK perf
    GEN python/perf.so

  real    0m1.701s
  user    0m1.338s
  sys     0m0.301s

Add the (trivial) dependencies to not force a re-link.

This speeds up an empty re-build enormously:

  comet:~/tip/tools/perf> time make

  ...

  real    0m0.207s
  user    0m0.134s
  sys     0m0.028s

[ This adds some coupling between the build dependencies of
  libtraceevent and liblk - but until those stay relatively
  simple this should not be an issue. ]

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-wvmlrurufuk6mo1ovtNigguT@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar 2013-10-01 17:17:22 +02:00
parent c72e3f04b4
commit c9404c6650
1 changed files with 7 additions and 3 deletions
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10
tools/perf/Makefile
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@ -669,15 +669,19 @@ $(LIB_FILE): $(LIB_OBJS)
$(QUIET_AR)$(RM) $@ && $(AR) rcs $@ $(LIB_OBJS)
# libtraceevent.a
$(LIBTRACEEVENT):
TE_SOURCES = $(wildcard $(TRACE_EVENT_DIR)*.[ch])
$(LIBTRACEEVENT): $(TE_SOURCES)
$(QUIET_SUBDIR0)$(TRACE_EVENT_DIR) $(QUIET_SUBDIR1) O=$(OUTPUT) libtraceevent.a
$(LIBTRACEEVENT)-clean:
$(QUIET_SUBDIR0)$(TRACE_EVENT_DIR) $(QUIET_SUBDIR1) O=$(OUTPUT) clean
LIBLK_SOURCES = $(wildcard $(LK_PATH)*.[ch])
# if subdir is set, we've been called from above so target has been built
# already
$(LIBLK):
$(LIBLK): $(LIBLK_SOURCES)
ifeq ($(subdir),)
$(QUIET_SUBDIR0)$(LK_DIR) $(QUIET_SUBDIR1) O=$(OUTPUT) liblk.a
endif
@ -825,6 +829,6 @@ else
GIT-HEAD-PHONY =
endif
.PHONY: all install clean strip $(LIBTRACEEVENT) $(LIBLK)
.PHONY: all install clean strip
.PHONY: shell_compatibility_test please_set_SHELL_PATH_to_a_more_modern_shell
.PHONY: $(GIT-HEAD-PHONY) TAGS tags cscope .FORCE-PERF-CFLAGS