tools/perf/build: Fix timerfd feature check

'feature_timerfd' is checked all the time and calculated explicitly,
in a serial fashion. Add it to CORE_FEATURE_TESTS which causes it to
be built in parallel, using the newfangled parallel build autodetection
code.

This shaves 137 msecs off the perf build time on my system, which
speeds up the common case cached build by 43%:

Before:

  comet:~/tip> perf stat --null --repeat 5 make -C tools/perf/
  [...]
         0,453771441 seconds time elapsed                                          ( +-  0,09% )

After:

  comet:~/tip> perf stat --null --repeat 5 make -C tools/perf/
  [...]
         0,316290185 seconds time elapsed                                          ( +-  0,24% )

Cc: David Ahern <dsahern@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-bb92CmexihopoSyqnkqepvsy@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/tools/perf/config/Makefile b/tools/perf/config/Makefile
index f5905f2b197d81d7cb2c8e0ee5a3f2cc257d5f20..861379ec7632f0b4a73b313e8e7b217b2733bda3 100644 (file)
--- a/tools/perf/config/Makefile
+++ b/tools/perf/config/Makefile
@@ -142,7 +142,8 @@ CORE_FEATURE_TESTS =                        \
        libunwind                       \
        on-exit                         \
        stackprotector                  \
-       stackprotector-all
+       stackprotector-all              \
+       timerfd
 
 #
 # So here we detect whether test-all was rebuilt, to be able
@@ -405,7 +406,6 @@ else
   endif
 endif
 
-$(call feature_check,timerfd)
 ifeq ($(feature-timerfd), 1)
   CFLAGS += -DHAVE_TIMERFD_SUPPORT
 else