This is important - see below.

Once this change is released I will send a patch to update the HOWTO.md on github.

Mathieu

---------- Forwarded message ---------
From: Arnaldo Carvalho de Melo <acme@kernel.org>
Date: Tue, 12 Feb 2019 at 11:04
Subject: HEADS UP: disable building with opencsd by default
To: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>, Kim Phillips <kim.phillips@arm.com>, <linux-arm-kernel@lists.infradead.org>, Mike Leach <mike.leach@arm.com>, Namhyung Kim <namhyung@kernel.org>, Peter Zijlstra <peterz@infradead.org>, Suzuki Poulouse <suzuki.poulose@arm.com>, Ingo Molnar <mingo@kernel.org>


Please see the rationale on the cset, this test-all.c thing was done by
Ingo long ago to speed up the build of the tools by checking first if
the common set of libraries is present, and because this isn't being
properly checked I left several cases pass, like opencsd, libaio and
libcrypto, that I'm working as well and have fixes in my perf/core
branch.

- Arnaldo

commit b7213083e3f3d69fffb5229034b3ac3ca9d41038
Author: Arnaldo Carvalho de Melo <acme@redhat.com>
Date:   Tue Feb 12 14:37:15 2019 -0300

    perf coresight: Do not test for libopencsd by default

    Since it is not yet that generally available, avoid testing for the
    presence of libcoresight in the fast path test-all.bin feature test.

      # dnf search opencsd
      No matches found.
      # dnf search OpenCSD
      No matches found.
      # cat /etc/fedora-release
      Fedora release 29 (Twenty Nine)
      #

    I.e. right now, in my system test-all.bin is failing all the time since
    Fedora29 doesn't have libopencsd available:

      $ cat /tmp/build/perf/feature/test-all.make.output
      In file included from test-all.c:174:
      test-libopencsd.c:2:10: fatal error: opencsd/c_api/opencsd_c_api.h: No such file or directory
       #include <opencsd/c_api/opencsd_c_api.h>
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      compilation terminated.

    See:

      6ab2b762befd ("perf build: Disable libbabeltrace check by default")

    For the rationale, as soon as libopencsd becomes more generally packaged
    and available, we do the same thing we did with babeltrace, enabling it
    by default, as done in:

      24787afbcd01 ("perf tools: Enable LIBBABELTRACE by default")

    For now, to explicitely ask for opencsd, make sure you have it installed
    and use:

       make -C tools/perf CORESIGHT=1

    The feature test output will be there as an empty file:

      $ ls -la /tmp/build/perf/feature/test-libopencsd.make.output

    Because the binary used for the feature check was successfully built:

      $ ls -la /tmp/build/perf/feature/test-libopencsd.bin
      -rwxrwxr-x. 1 acme acme 18336 Feb 12 14:49 /tmp/build/perf/feature/test-libopencsd.bin
      $ ldd /tmp/build/perf/feature/test-libopencsd.bin
            linux-vdso.so.1 (0x00007fffe18cc000)
            libopencsd_c_api.so.0 => /lib64/libopencsd_c_api.so.0 (0x00007fb8e67f6000)
            libopencsd.so.0 => /lib64/libopencsd.so.0 (0x00007fb8e676f000)
            libc.so.6 => /lib64/libc.so.6 (0x00007fb8e65a9000)
            libstdc++.so.6 => /lib64/libstdc++.so.6 (0x00007fb8e6411000)
            libm.so.6 => /lib64/libm.so.6 (0x00007fb8e628d000)
            libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007fb8e6272000)
            /lib64/ld-linux-x86-64.so.2 (0x00007fb8e6828000)
      $

    And the resulting perf binary will be linked with it:

      -rw-rw-r--. 1 acme acme 0 Feb 12 14:49 /tmp/build/perf/feature/test-libopencsd.make.output
      $ ldd ~/bin/perf | grep opencsd
            libopencsd_c_api.so.0 => /lib64/libopencsd_c_api.so.0 (0x00007fd43097f000)
            libopencsd.so.0 => /lib64/libopencsd.so.0 (0x00007fd4308f8000)
      $

    To make sure this gets built before pushing things upstream I have a
    ubuntu:19.04-x-arm64 container that has:

      [root@quaco x-arm64]# grep CORESIGHT Dockerfile
      ENV EXTRA_MAKE_ARGS=CORESIGHT=1
      [root@quaco x-arm64]#

    So that I always build with libopencsd before pushing things upstream.

    Cc: Adrian Hunter <adrian.hunter@intel.com>
    Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
    Cc: Jiri Olsa <jolsa@kernel.org>
    Cc: Kim Phillips <kim.phillips@arm.com>
    Cc: linux-arm-kernel@lists.infradead.org
    Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
    Cc: Mike Leach <mike.leach@arm.com>
    Cc: Namhyung Kim <namhyung@kernel.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
    Link: https://lkml.kernel.org/n/tip-20vyy39jw9jgrijesi30fgox@git.kernel.org
    Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
index 5467c6bf9ceb..bb9dca65eb5f 100644
--- a/tools/build/Makefile.feature
+++ b/tools/build/Makefile.feature
@@ -70,7 +70,6 @@ FEATURE_TESTS_BASIC :=                  \
         sched_getcpu                   \
         sdt                            \
         setns                          \
-        libopencsd                     \
         libaio

 # FEATURE_TESTS_BASIC + FEATURE_TESTS_EXTRA is the complete list
@@ -84,6 +83,7 @@ FEATURE_TESTS_EXTRA :=                  \
          libbabeltrace                  \
          libbfd-liberty                 \
          libbfd-liberty-z               \
+         libopencsd                     \
          libunwind-debug-frame          \
          libunwind-debug-frame-arm      \
          libunwind-debug-frame-aarch64  \
diff --git a/tools/build/feature/test-all.c b/tools/build/feature/test-all.c
index 20cdaa4fc112..74329957553a 100644
--- a/tools/build/feature/test-all.c
+++ b/tools/build/feature/test-all.c
@@ -170,10 +170,6 @@
 # include "test-setns.c"
 #undef main

-#define main main_test_libopencsd
-# include "test-libopencsd.c"
-#undef main
-
 #define main main_test_libaio
 # include "test-libaio.c"
 #undef main
@@ -217,7 +213,6 @@ int main(int argc, char *argv[])
        main_test_sched_getcpu();
        main_test_sdt();
        main_test_setns();
-       main_test_libopencsd();
        main_test_libaio();

        return 0;
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index b441c88cafa1..e3bf29f942a8 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -386,7 +386,8 @@ ifeq ($(feature-setns), 1)
   $(call detected,CONFIG_SETNS)
 endif

-ifndef NO_CORESIGHT
+ifdef CORESIGHT
+  $(call feature_check,libopencsd)
   ifeq ($(feature-libopencsd), 1)
     CFLAGS += -DHAVE_CSTRACE_SUPPORT $(LIBOPENCSD_CFLAGS)
     LDFLAGS += $(LIBOPENCSD_LDFLAGS)
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 09df1c8a4ec9..c2ccc54618d1 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -102,7 +102,7 @@ include ../scripts/utilities.mak
 # When selected, pass LLVM_CONFIG=/path/to/llvm-config to `make' if
 # llvm-config is not in $PATH.
 #
-# Define NO_CORESIGHT if you do not want support for CoreSight trace decoding.
+# Define CORESIGHT if you DO WANT support for CoreSight trace decoding.
 #
 # Define NO_AIO if you do not want support of Posix AIO based trace
 # streaming for record mode. Currently Posix AIO trace streaming is