<feed xmlns='http://www.w3.org/2005/Atom'>
<title>lwn.git/tools/build/Makefile.feature, branch docs-5.0-fix</title>
<subtitle>Linux kernel documentation tree maintained by Jonathan Corbet</subtitle>
<id>http://mirrors.hust.edu.cn/git/lwn.git/atom?h=docs-5.0-fix</id>
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<updated>2018-12-21T12:42:46+00:00</updated>
<entry>
<title>perf build: Don't unconditionally link the libbfd feature test to -liberty and -lz</title>
<updated>2018-12-21T12:42:46+00:00</updated>
<author>
<name>Stanislav Fomichev</name>
<email>sdf@google.com</email>
</author>
<published>2018-11-16T00:32:01+00:00</published>
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<id>urn:sha1:14541b1e7e723859ff2c75c6fc10cdbbec6b8c34</id>
<content type='text'>
Current libbfd feature test unconditionally links against -liberty and -lz.
While it's required on some systems (e.g. opensuse), it's completely
unnecessary on the others, where only -lbdf is sufficient (debian).
This patch streamlines (and renames) the following feature checks:

feature-libbfd           - only link against -lbfd (debian),
                           see commit 2cf9040714f3 ("perf tools: Fix bfd
			   dependency libraries detection")
feature-libbfd-liberty   - link against -lbfd and -liberty
feature-libbfd-liberty-z - link against -lbfd, -liberty and -lz (opensuse),
                           see commit 280e7c48c3b8 ("perf tools: fix BFD
			   detection on opensuse")

(feature-liberty{,-z} were renamed to feature-libbfd-liberty{,z}
for clarity)

The main motivation is to fix this feature test for bpftool which is
currently broken on debian (libbfd feature shows OFF, but we still
unconditionally link against -lbfd and it works).

Tested on debian with only -lbfd installed (without -liberty); I'd
appreciate if somebody on the other systems can test this new detection
method.

Signed-off-by: Stanislav Fomichev &lt;sdf@google.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lkml.kernel.org/r/4dfc634cfcfb236883971b5107cf3c28ec8a31be.1542328222.git.sdf@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>tools build feature: Check if libaio is available</title>
<updated>2018-12-17T17:54:54+00:00</updated>
<author>
<name>Alexey Budankov</name>
<email>alexey.budankov@linux.intel.com</email>
</author>
<published>2018-11-06T09:03:35+00:00</published>
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<id>urn:sha1:2a07d814747b386feec7d7150fe519feb2a2a5f2</id>
<content type='text'>
This will be used by 'perf record' to speed up reading the perf ring
buffer.

Committer testing:

  $ make -C tools/perf O=/tmp/build/perf
  make: Entering directory '/home/acme/git/perf/tools/perf'
    BUILD:   Doing 'make -j8' parallel build

  Auto-detecting system features:
  ...                         dwarf: [ on  ]
  ...            dwarf_getlocations: [ on  ]
  ...                         glibc: [ on  ]
  ...                          gtk2: [ OFF ]
  ...                      libaudit: [ OFF ]
  ...                        libbfd: [ OFF ]
  ...                        libelf: [ on  ]
  ...                       libnuma: [ OFF ]
  ...        numa_num_possible_cpus: [ OFF ]
  ...                       libperl: [ OFF ]
  ...                     libpython: [ OFF ]
  ...                      libslang: [ on  ]
  ...                     libcrypto: [ on  ]
  ...                     libunwind: [ on  ]
  ...            libdw-dwarf-unwind: [ on  ]
  ...                          zlib: [ on  ]
  ...                          lzma: [ on  ]
  ...                     get_cpuid: [ on  ]
  ...                           bpf: [ on  ]
  ...                        libaio: [ on  ]

  $ ls -la /tmp/build/perf/feature/test-libaio.*
  -rwxrwxr-x. 1 acme acme 18296 Nov 26 08:49 /tmp/build/perf/feature/test-libaio.bin
  -rw-rw-r--. 1 acme acme  1165 Nov 26 08:49 /tmp/build/perf/feature/test-libaio.d
  -rw-rw-r--. 1 acme acme     0 Nov 26 08:49 /tmp/build/perf/feature/test-libaio.make.output
  $
  $ grep -i aio /tmp/build/perf/FEATURE-DUMP
  feature-libaio=1
  $

Signed-off-by: Alexey Budankov &lt;alexey.budankov@linux.intel.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Reviewed-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Acked-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lkml.kernel.org/r/5fcda10c-6c63-68df-383a-c6d9e5d1f918@linux.intel.com
[ split from a larger patch ]
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>tools build feature: Check if eventfd() is available</title>
<updated>2018-11-22T01:25:44+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2018-11-21T20:42:00+00:00</published>
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<id>urn:sha1:11c6cbe706f218a8dc7e1f962f12b3a52ddd33a9</id>
<content type='text'>
A new 'perf bench epoll' will use this, and to disable it for older
systems, add a feature test for this API.

This is just a simple program that if successfully compiled, means that
the feature is present, at least at the library level, in a build that
sets the output directory to /tmp/build/perf (using O=/tmp/build/perf),
we end up with:

  $ ls -la /tmp/build/perf/feature/test-eventfd*
  -rwxrwxr-x. 1 acme acme 8176 Nov 21 15:58 /tmp/build/perf/feature/test-eventfd.bin
  -rw-rw-r--. 1 acme acme  588 Nov 21 15:58 /tmp/build/perf/feature/test-eventfd.d
  -rw-rw-r--. 1 acme acme    0 Nov 21 15:58 /tmp/build/perf/feature/test-eventfd.make.output
  $ ldd /tmp/build/perf/feature/test-eventfd.bin
	  linux-vdso.so.1 (0x00007fff3bf3f000)
	  libc.so.6 =&gt; /lib64/libc.so.6 (0x00007fa984061000)
	  /lib64/ld-linux-x86-64.so.2 (0x00007fa984417000)
  $ grep eventfd -A 2 -B 2 /tmp/build/perf/FEATURE-DUMP
  feature-dwarf=1
  feature-dwarf_getlocations=1
  feature-eventfd=1
  feature-fortify-source=1
  feature-sync-compare-and-swap=1
  $

The main thing here is that in the end we'll have -DHAVE_EVENTFD in
CFLAGS, and then the 'perf bench' entry needing that API can be
selectively pruned.

Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: David Ahern &lt;dsahern@gmail.com&gt;
Cc: Davidlohr Bueso &lt;dbueso@suse.de&gt;
Cc: Jason Baron &lt;jbaron@akamai.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Link: https://lkml.kernel.org/n/tip-wkeldwob7dpx6jvtuzl8164k@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>tools build feature: Check if get_current_dir_name() is available</title>
<updated>2018-11-19T20:12:17+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2018-11-19T19:56:22+00:00</published>
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<id>urn:sha1:8feb8efef97a134933620071e0b6384cb3238b4e</id>
<content type='text'>
As the namespace support code will use this, which is not available in
some non _GNU_SOURCE libraries such as Android's bionic used in my
container build tests (r12b and r15c at the moment).

Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: David Ahern &lt;dsahern@gmail.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Link: https://lkml.kernel.org/n/tip-x56ypm940pwclwu45d7jfj47@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>tools: include reallocarray feature test in FEATURE_TESTS_BASIC</title>
<updated>2018-07-14T08:38:48+00:00</updated>
<author>
<name>Jakub Kicinski</name>
<email>jakub.kicinski@netronome.com</email>
</author>
<published>2018-07-14T02:08:59+00:00</published>
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<id>urn:sha1:db42a21a1e8d11a30a06050281c2723ec78b63a7</id>
<content type='text'>
perf propagates its feature check results to libbpf.  This means
features for which perf probes must be a superset of libbpf's
required features.  perf depends on FEATURE_TESTS_BASIC for its list
of features.

commit 531b014e7a2f ("tools: bpf: make use of reallocarray") added
reallocarray use to libbpf, make perf also perform the reallocarray
feature check.

Fixes: 531b014e7a2f ("tools: bpf: make use of reallocarray")
Reported-by: Guenter Roeck &lt;linux@roeck-us.net&gt;
Signed-off-by: Jakub Kicinski &lt;jakub.kicinski@netronome.com&gt;
Tested-by: Guenter Roeck &lt;linux@roeck-us.net&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
</content>
</entry>
<entry>
<title>perf build: Add llvm/clang/cxx make tests into FEATURE_TESTS_EXTRA</title>
<updated>2018-03-08T14:30:48+00:00</updated>
<author>
<name>Jiri Olsa</name>
<email>jolsa@kernel.org</email>
</author>
<published>2018-03-07T15:50:18+00:00</published>
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<id>urn:sha1:bd476684584ecc3e269167d595c6dd5375011ca0</id>
<content type='text'>
So we can see the status when we build perf, like:

  $ make LIBCLANGLLVM=1 VF=1
  ...                           cxx: [ on  ]
  ...                          llvm: [ on  ]
  ...                  llvm-version: [ on  ]
  ...                         clang: [ on  ]

Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: David Ahern &lt;dsahern@gmail.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lkml.kernel.org/r/20180307155020.32613-18-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf tools: Integrating the CoreSight decoding library</title>
<updated>2018-01-25T09:37:23+00:00</updated>
<author>
<name>Mathieu Poirier</name>
<email>mathieu.poirier@linaro.org</email>
</author>
<published>2018-01-17T17:52:10+00:00</published>
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<id>urn:sha1:aa6292f4845e7921fca60b146403ea6682b8f65d</id>
<content type='text'>
The Open CoreSight Decoding Library (openCSD) is a free and open library
to decode traces collected by the CoreSight hardware infrastructure.

This patch adds the required mechanic to recognise the presence of the
openCSD library on a system and set up miscellaneous flags to be used in
the compilation of the trace decoding feature.

Signed-off-by: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Kim Phillips &lt;kim.phillips@arm.com&gt;
Cc: linux-arm-kernel@lists.infradead.org
Cc: Mike Leach &lt;mike.leach@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Suzuki Poulouse &lt;suzuki.poulose@arm.com&gt;
Link: http://lkml.kernel.org/r/1516211539-5166-2-git-send-email-mathieu.poirier@linaro.org
Link: http://lkml.kernel.org/r/1516635644-24819-1-git-send-email-mathieu.poirier@linaro.org
[ Merged missing test-libopencsd.c file, provided later by Mathieu ]
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>tools build feature: Check if pthread_barrier_t is available</title>
<updated>2017-12-05T13:21:59+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2017-12-05T13:14:42+00:00</published>
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<id>urn:sha1:25ab5abf5b141d7fd13eed506c7458aa04749c29</id>
<content type='text'>
As 'perf bench futex wake-parallel" will use this, which is not
available in older systems such as versions of the android NDK used in
my container build tests (r12b and r15c at the moment).

Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: David Ahern &lt;dsahern@gmail.com&gt;
Cc: Davidlohr Bueso &lt;dave@stgolabs.net&gt;
Cc: James Yang &lt;james.yang@arm.com
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Kim Phillips &lt;kim.phillips@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Link: https://lkml.kernel.org/n/tip-1i7iv54in4wj08lwo55b0pzv@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>tools build: Add test for setns()</title>
<updated>2017-07-19T02:14:08+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2017-07-18T20:15:29+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=86bcdb5a43997bb02ba25a76482c7bfc652ba45b'/>
<id>urn:sha1:86bcdb5a43997bb02ba25a76482c7bfc652ba45b</id>
<content type='text'>
And provide an alternative implementation to keep perf building on older
distros as we're about to add initial support for namespaces.

Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: David Ahern &lt;dsahern@gmail.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Krister Johansen &lt;kjlx@templeofstupid.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Link: http://lkml.kernel.org/n/tip-bqdwijunhjlvps1ardykhw1i@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>tools build: Add test for sched_getcpu()</title>
<updated>2017-03-03T22:07:19+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2017-03-02T15:55:49+00:00</published>
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<id>urn:sha1:120010cb1eea151d38a3e66f5ffc79a0c3110292</id>
<content type='text'>
Instead of trying to go on adding more ifdef conditions, do a feature
test and define HAVE_SCHED_GETCPU_SUPPORT instead, then use it to
provide the prototype. No need to change the stub, as it is already a
__weak symbol.

Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: David Ahern &lt;dsahern@gmail.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Wang Nan &lt;wangnan0@huawei.com&gt;
Link: http://lkml.kernel.org/n/tip-yge89er9g90sc0v6k0a0r5tr@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
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