<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/linux.git/tools/build/Makefile.feature, branch v5.19</title>
<subtitle>Linux kernel stable tree (mirror)</subtitle>
<id>https://git.radix-linux.su/kernel/linux.git/atom?h=v5.19</id>
<link rel='self' href='https://git.radix-linux.su/kernel/linux.git/atom?h=v5.19'/>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/'/>
<updated>2022-05-26T15:36:56+00:00</updated>
<entry>
<title>perf build: Stop using __weak bpf_map_create() to handle older libbpf versions</title>
<updated>2022-05-26T15:36:56+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2022-05-26T14:48:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=df76e0038370d364d4b2154fa7ddbbccc29f629f'/>
<id>urn:sha1:df76e0038370d364d4b2154fa7ddbbccc29f629f</id>
<content type='text'>
By adding a feature test for bpf_map_create() and providing a fallback if
it isn't present in older versions of libbpf.

This also fixes the build with torvalds/master at this point:

  $ git log --oneline -5 torvalds/master
  babf0bb978e3c9fc (torvalds/master) Merge tag 'xfs-5.19-for-linus' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
  e375780b631a5fc2 Merge tag 'fsnotify_for_v5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
  8b728edc5be16179 Merge tag 'fs_for_v5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
  3f306ea2e18568f6 Merge tag 'dma-mapping-5.19-2022-05-25' of git://git.infradead.org/users/hch/dma-mapping
  fbe86daca0ba878b Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
  $

Coping with:

  $ git log --oneline -2 d16495a982324f75
  d16495a982324f75 libbpf: remove bpf_create_map*() APIs
  e2371b1632b1c61c libbpf: start 1.0 development cycle
  $

As the __weak function fails to build as it calls the now removed
bpf_create_map() API.

Testing:

  $ rpm -q libbpf-devel
  libbpf-devel-0.4.0-2.fc35.x86_64
  $
  $ make -C tools/perf BUILD_BPF_SKEL=1 LIBBPF_DYNAMIC=1 O=/tmp/build/perf install-bin
  $ cat /tmp/build/perf/feature/test-libbpf-bpf_map_create.make.output
  test-libbpf-bpf_map_create.c: In function ‘main’:
  test-libbpf-bpf_map_create.c:6:16: error: implicit declaration of function ‘bpf_map_create’; did you mean ‘bpf_map_freeze’? [-Werror=implicit-function-declaration]
      6 |         return bpf_map_create(0 /* map_type */, NULL /* map_name */, 0, /* key_size */,
        |                ^~~~~~~~~~~~~~
        |                bpf_map_freeze
  test-libbpf-bpf_map_create.c:6:87: error: expected expression before ‘,’ token
      6 |         return bpf_map_create(0 /* map_type */, NULL /* map_name */, 0, /* key_size */,
        |                                                                                       ^
  cc1: all warnings being treated as errors
  $
  $ objdump -dS /tmp/build/perf/perf | grep '&lt;bpf_map_create&gt;:' -A20
  000000000058b290 &lt;bpf_map_create&gt;:
  {
    58b290:	55                   	push   %rbp
    58b291:	48 89 e5             	mov    %rsp,%rbp
    58b294:	48 83 ec 10          	sub    $0x10,%rsp
    58b298:	64 48 8b 04 25 28 00 	mov    %fs:0x28,%rax
    58b29f:	00 00
    58b2a1:	48 89 45 f8          	mov    %rax,-0x8(%rbp)
    58b2a5:	31 c0                	xor    %eax,%eax
  	return bpf_create_map(map_type, key_size, value_size, max_entries, 0);
    58b2a7:	48 8b 45 f8          	mov    -0x8(%rbp),%rax
    58b2ab:	64 48 2b 04 25 28 00 	sub    %fs:0x28,%rax
    58b2b2:	00 00
    58b2b4:	75 10                	jne    58b2c6 &lt;bpf_map_create+0x36&gt;
  }
    58b2b6:	c9                   	leave
    58b2b7:	89 d6                	mov    %edx,%esi
    58b2b9:	89 ca                	mov    %ecx,%edx
    58b2bb:	44 89 c1             	mov    %r8d,%ecx
  	return bpf_create_map(map_type, key_size, value_size, max_entries, 0);
    58b2be:	45 31 c0             	xor    %r8d,%r8d
  $

Cc: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Cc: Heiko Carstens &lt;hca@linux.ibm.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Ilya Leoshkevich &lt;iii@linux.ibm.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Song Liu &lt;songliubraving@fb.com&gt;
Cc: Sumanth Korikkar &lt;sumanthk@linux.ibm.com&gt;
Cc: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Cc: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Link: http://lore.kernel.org/linux-perf-users/Yo+XvQNKL4K5khl2@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf build: Stop using __weak bpf_object__next_map() to handle older libbpf versions</title>
<updated>2022-05-26T14:02:02+00:00</updated>
<author>
<name>Jiri Olsa</name>
<email>jolsa@kernel.org</email>
</author>
<published>2022-05-24T11:13:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=739c9180cfa487cc92e2721e224564e4672c578e'/>
<id>urn:sha1:739c9180cfa487cc92e2721e224564e4672c578e</id>
<content type='text'>
By adding a feature test for bpf_object__next_map() and providing a fallback if
it isn't present in older versions of libbpf.

Committer testing:

  $ rpm -q libbpf-devel
  libbpf-devel-0.4.0-2.fc35.x86_64
  $ make -C tools/perf LIBBPF_DYNAMIC=1 O=/tmp/build/perf install-bin
  $ cat /tmp/build/perf/feature/test-libbpf-bpf_object__next_map.make.output
  test-libbpf-bpf_object__next_map.c: In function ‘main’:
  test-libbpf-bpf_object__next_map.c:6:9: error: implicit declaration of function ‘bpf_object__next_map’; did you mean ‘bpf_object__next’? [-Werror=implicit-function-declaration]
      6 |         bpf_object__next_map(NULL /* obj */, NULL /* prev */);
        |         ^~~~~~~~~~~~~~~~~~~~
        |         bpf_object__next
    cc1: all warnings being treated as errors
  $
  $ objdump -dS /tmp/build/perf/perf | grep '&lt;bpf_object__next_map&gt;:' -A20
  00000000005b2e00 &lt;bpf_object__next_map&gt;:
  {
    5b2e00:	55                   	push   %rbp
    5b2e01:	48 89 e5             	mov    %rsp,%rbp
    5b2e04:	48 83 ec 10          	sub    $0x10,%rsp
    5b2e08:	64 48 8b 04 25 28 00 	mov    %fs:0x28,%rax
    5b2e0f:	00 00
    5b2e11:	48 89 45 f8          	mov    %rax,-0x8(%rbp)
    5b2e15:	31 c0                	xor    %eax,%eax
	  return bpf_map__next(prev, obj);
    5b2e17:	48 8b 45 f8          	mov    -0x8(%rbp),%rax
    5b2e1b:	64 48 2b 04 25 28 00 	sub    %fs:0x28,%rax
    5b2e22:	00 00
    5b2e24:	75 0f                	jne    5b2e35 &lt;bpf_object__next_map+0x35&gt;
  }
    5b2e26:	c9                   	leave
    5b2e27:	49 89 f8             	mov    %rdi,%r8
    5b2e2a:	48 89 f7             	mov    %rsi,%rdi
	  return bpf_map__next(prev, obj);
    5b2e2d:	4c 89 c6             	mov    %r8,%rsi
    5b2e30:	e9 cb b1 e5 ff       	jmp    40e000 &lt;bpf_map__next@plt&gt;
  $

Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Heiko Carstens &lt;hca@linux.ibm.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Ilya Leoshkevich &lt;iii@linux.ibm.com&gt;
Cc: Sumanth Korikkar &lt;sumanthk@linux.ibm.com&gt;
Cc: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Cc: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Link: http://lore.kernel.org/linux-perf-users/YozLKby7ITEtchC9@krava
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf build: Stop using __weak bpf_object__next_program() to handle older libbpf versions</title>
<updated>2022-05-26T14:02:02+00:00</updated>
<author>
<name>Jiri Olsa</name>
<email>jolsa@kernel.org</email>
</author>
<published>2022-05-24T11:09:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=8916d72554e5f06df5ba17bfabc87c7977294ba4'/>
<id>urn:sha1:8916d72554e5f06df5ba17bfabc87c7977294ba4</id>
<content type='text'>
By adding a feature test for bpf_object__next_program() and providing a fallback if
it isn't present in older versions of libbpf.

Committer testing:

  $ rpm -q libbpf-devel
  libbpf-devel-0.4.0-2.fc35.x86_64
  $ make -C tools/perf LIBBPF_DYNAMIC=1 O=/tmp/build/perf install-bin
  $ cat /tmp/build/perf/feature/test-libbpf-bpf_object__next_program.make.output
  test-libbpf-bpf_object__next_program.c: In function ‘main’:
  test-libbpf-bpf_object__next_program.c:6:9: error: implicit declaration of function ‘bpf_object__next_program’; did you mean ‘bpf_object__unpin_programs’? [-Werror=implicit-function-declaration]
      6 |         bpf_object__next_program(NULL /* obj */, NULL /* prev */);
        |         ^~~~~~~~~~~~~~~~~~~~~~~~
        |         bpf_object__unpin_programs
  cc1: all warnings being treated as errors
  $
  $ objdump -dS /tmp/build/perf/perf | grep '&lt;bpf_object__next_program&gt;:' -A20
  00000000005b2dc0 &lt;bpf_object__next_program&gt;:
  {
    5b2dc0:	55                   	push   %rbp
    5b2dc1:	48 89 e5             	mov    %rsp,%rbp
    5b2dc4:	48 83 ec 10          	sub    $0x10,%rsp
    5b2dc8:	64 48 8b 04 25 28 00 	mov    %fs:0x28,%rax
    5b2dcf:	00 00
    5b2dd1:	48 89 45 f8          	mov    %rax,-0x8(%rbp)
    5b2dd5:	31 c0                	xor    %eax,%eax
	  return bpf_program__next(prev, obj);
    5b2dd7:	48 8b 45 f8          	mov    -0x8(%rbp),%rax
    5b2ddb:	64 48 2b 04 25 28 00 	sub    %fs:0x28,%rax
    5b2de2:	00 00
    5b2de4:	75 0f                	jne    5b2df5 &lt;bpf_object__next_program+0x35&gt;
  }
    5b2de6:	c9                   	leave
    5b2de7:	49 89 f8             	mov    %rdi,%r8
    5b2dea:	48 89 f7             	mov    %rsi,%rdi
	  return bpf_program__next(prev, obj);
    5b2ded:	4c 89 c6             	mov    %r8,%rsi
    5b2df0:	e9 3b b4 e5 ff       	jmp    40e230 &lt;bpf_program__next@plt&gt;
    $

Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Heiko Carstens &lt;hca@linux.ibm.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Ilya Leoshkevich &lt;iii@linux.ibm.com&gt;
Cc: Sumanth Korikkar &lt;sumanthk@linux.ibm.com&gt;
Cc: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Cc: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Link: http://lore.kernel.org/linux-perf-users/YozLKby7ITEtchC9@krava
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf build: Stop using __weak bpf_prog_load() to handle older libbpf versions</title>
<updated>2022-05-26T14:02:02+00:00</updated>
<author>
<name>Jiri Olsa</name>
<email>jolsa@kernel.org</email>
</author>
<published>2022-05-24T11:04:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=5c83eff38194ab2c69a7dc1a64a0a3683f0a3c3a'/>
<id>urn:sha1:5c83eff38194ab2c69a7dc1a64a0a3683f0a3c3a</id>
<content type='text'>
By adding a feature test for bpf_prog_load() and providing a fallback if
it isn't present in older versions of libbpf.

Committer testing:

  $ rpm -q libbpf-devel
  libbpf-devel-0.4.0-2.fc35.x86_64
  $ make -C tools/perf LIBBPF_DYNAMIC=1 O=/tmp/build/perf install-bin
  $ cat /tmp/build/perf/feature/test-libbpf-bpf_prog_load.make.output
  test-libbpf-bpf_prog_load.c: In function ‘main’:
  test-libbpf-bpf_prog_load.c:6:16: error: implicit declaration of function ‘bpf_prog_load’ [-Werror=implicit-function-declaration]
      6 |         return bpf_prog_load(0 /* prog_type */, NULL /* prog_name */,
        |                ^~~~~~~~~~~~~
  cc1: all warnings being treated as errors
  $

  $ objdump -dS /tmp/build/perf/perf | grep '&lt;bpf_prog_load&gt;:' -A20
  00000000005b2d70 &lt;bpf_prog_load&gt;:
  {
    5b2d70:	55                   	push   %rbp
    5b2d71:	48 89 ce             	mov    %rcx,%rsi
    5b2d74:	4c 89 c8             	mov    %r9,%rax
    5b2d77:	49 89 d2             	mov    %rdx,%r10
    5b2d7a:	4c 89 c2             	mov    %r8,%rdx
    5b2d7d:	48 89 e5             	mov    %rsp,%rbp
    5b2d80:	48 83 ec 18          	sub    $0x18,%rsp
    5b2d84:	64 48 8b 0c 25 28 00 	mov    %fs:0x28,%rcx
    5b2d8b:	00 00
    5b2d8d:	48 89 4d f8          	mov    %rcx,-0x8(%rbp)
    5b2d91:	31 c9                	xor    %ecx,%ecx
  	return bpf_load_program(prog_type, insns, insn_cnt, license,
    5b2d93:	41 8b 49 5c          	mov    0x5c(%r9),%ecx
    5b2d97:	51                   	push   %rcx
    5b2d98:	4d 8b 49 60          	mov    0x60(%r9),%r9
    5b2d9c:	4c 89 d1             	mov    %r10,%rcx
    5b2d9f:	44 8b 40 1c          	mov    0x1c(%rax),%r8d
    5b2da3:	e8 f8 aa e5 ff       	call   40d8a0 &lt;bpf_load_program@plt&gt;
  }
  $

Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Heiko Carstens &lt;hca@linux.ibm.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Ilya Leoshkevich &lt;iii@linux.ibm.com&gt;
Cc: Sumanth Korikkar &lt;sumanthk@linux.ibm.com&gt;
Cc: Sven Schnelle &lt;svens@linux.ibm.com&gt;
Cc: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Link: http://lore.kernel.org/linux-perf-users/YozLKby7ITEtchC9@krava
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf build: Fix check for btf__load_from_kernel_by_id() in libbpf</title>
<updated>2022-05-20T12:45:41+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2022-05-20T00:25:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=0ae065a5d265bc5ada13e350015458e0c5e5c351'/>
<id>urn:sha1:0ae065a5d265bc5ada13e350015458e0c5e5c351</id>
<content type='text'>
Avi Kivity reported a problem where the __weak
btf__load_from_kernel_by_id() in tools/perf/util/bpf-event.c was being
used and it called btf__get_from_id() in tools/lib/bpf/btf.c that in
turn called back to btf__load_from_kernel_by_id(), resulting in an
endless loop.

Fix this by adding a feature test to check if
btf__load_from_kernel_by_id() is available when building perf with
LIBBPF_DYNAMIC=1, and if not then provide the fallback to the old
btf__get_from_id(), that doesn't call back to btf__load_from_kernel_by_id()
since at that time it didn't exist at all.

Tested on Fedora 35 where we have libbpf-devel 0.4.0 with LIBBPF_DYNAMIC
where we don't have btf__load_from_kernel_by_id() and thus its feature
test fail, not defining HAVE_LIBBPF_BTF__LOAD_FROM_KERNEL_BY_ID:

  $ cat /tmp/build/perf-urgent/feature/test-libbpf-btf__load_from_kernel_by_id.make.output
  test-libbpf-btf__load_from_kernel_by_id.c: In function ‘main’:
  test-libbpf-btf__load_from_kernel_by_id.c:6:16: error: implicit declaration of function ‘btf__load_from_kernel_by_id’ [-Werror=implicit-function-declaration]
      6 |         return btf__load_from_kernel_by_id(20151128, NULL);
        |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~
  cc1: all warnings being treated as errors
  $

  $ nm /tmp/build/perf-urgent/perf | grep btf__load_from_kernel_by_id
  00000000005ba180 T btf__load_from_kernel_by_id
  $

  $ objdump --disassemble=btf__load_from_kernel_by_id -S /tmp/build/perf-urgent/perf

  /tmp/build/perf-urgent/perf:     file format elf64-x86-64
  &lt;SNIP&gt;
  00000000005ba180 &lt;btf__load_from_kernel_by_id&gt;:
  #include "record.h"
  #include "util/synthetic-events.h"

  #ifndef HAVE_LIBBPF_BTF__LOAD_FROM_KERNEL_BY_ID
  struct btf *btf__load_from_kernel_by_id(__u32 id)
  {
    5ba180:	55                   	push   %rbp
    5ba181:	48 89 e5             	mov    %rsp,%rbp
    5ba184:	48 83 ec 10          	sub    $0x10,%rsp
    5ba188:	64 48 8b 04 25 28 00 	mov    %fs:0x28,%rax
    5ba18f:	00 00
    5ba191:	48 89 45 f8          	mov    %rax,-0x8(%rbp)
    5ba195:	31 c0                	xor    %eax,%eax
         struct btf *btf;
  #pragma GCC diagnostic push
  #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
         int err = btf__get_from_id(id, &amp;btf);
    5ba197:	48 8d 75 f0          	lea    -0x10(%rbp),%rsi
    5ba19b:	e8 a0 57 e5 ff       	call   40f940 &lt;btf__get_from_id@plt&gt;
    5ba1a0:	89 c2                	mov    %eax,%edx
  #pragma GCC diagnostic pop

         return err ? ERR_PTR(err) : btf;
    5ba1a2:	48 98                	cltq
    5ba1a4:	85 d2                	test   %edx,%edx
    5ba1a6:	48 0f 44 45 f0       	cmove  -0x10(%rbp),%rax
  }
  &lt;SNIP&gt;

Fixes: 218e7b775d368f38 ("perf bpf: Provide a weak btf__load_from_kernel_by_id() for older libbpf versions")
Reported-by: Avi Kivity &lt;avi@scylladb.com&gt;
Link: https://lore.kernel.org/linux-perf-users/f0add43b-3de5-20c5-22c4-70aff4af959f@scylladb.com
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lore.kernel.org/linux-perf-users/YobjjFOblY4Xvwo7@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>tools build: Remove needless libpython-version feature check that breaks test-all fast path</title>
<updated>2021-12-07T00:57:53+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2021-11-30T13:12:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=3d1d57debee2d342a47615707588b96658fabb85'/>
<id>urn:sha1:3d1d57debee2d342a47615707588b96658fabb85</id>
<content type='text'>
Since 66dfdff03d196e51 ("perf tools: Add Python 3 support") we don't use
the tools/build/feature/test-libpython-version.c version in any Makefile
feature check:

  $ find tools/ -type f | xargs grep feature-libpython-version
  $

The only place where this was used was removed in 66dfdff03d196e51:

  -        ifneq ($(feature-libpython-version), 1)
  -          $(warning Python 3 is not yet supported; please set)
  -          $(warning PYTHON and/or PYTHON_CONFIG appropriately.)
  -          $(warning If you also have Python 2 installed, then)
  -          $(warning try something like:)
  -          $(warning $(and ,))
  -          $(warning $(and ,)  make PYTHON=python2)
  -          $(warning $(and ,))
  -          $(warning Otherwise, disable Python support entirely:)
  -          $(warning $(and ,))
  -          $(warning $(and ,)  make NO_LIBPYTHON=1)
  -          $(warning $(and ,))
  -          $(error   $(and ,))
  -        else
  -          LDFLAGS += $(PYTHON_EMBED_LDFLAGS)
  -          EXTLIBS += $(PYTHON_EMBED_LIBADD)
  -          LANG_BINDINGS += $(obj-perf)python/perf.so
  -          $(call detected,CONFIG_LIBPYTHON)
  -        endif

And nowadays we either build with PYTHON=python3 or just install the
python3 devel packages and perf will build against it.

But the leftover feature-libpython-version check made the fast path
feature detection to break in all cases except when python2 devel files
were installed:

  $ rpm -qa | grep python.*devel
  python3-devel-3.9.7-1.fc34.x86_64
  $ rm -rf /tmp/build/perf ; mkdir -p /tmp/build/perf ;
  $ make -C tools/perf O=/tmp/build/perf install-bin
  make: Entering directory '/var/home/acme/git/perf/tools/perf'
    BUILD:   Doing 'make -j32' parallel build
    HOSTCC  /tmp/build/perf/fixdep.o
  &lt;SNIP&gt;
  $ cat /tmp/build/perf/feature/test-all.make.output
  In file included from test-all.c:18:
  test-libpython-version.c:5:10: error: #error
      5 |         #error
        |          ^~~~~
  $ ldd ~/bin/perf | grep python
	libpython3.9.so.1.0 =&gt; /lib64/libpython3.9.so.1.0 (0x00007fda6dbcf000)
  $

As python3 is the norm these days, fix this by just removing the unused
feature-libpython-version feature check, making the test-all fast path
to work with the common case.

With this:

  $ rm -rf /tmp/build/perf ; mkdir -p /tmp/build/perf ;
  $ make -C tools/perf O=/tmp/build/perf install-bin |&amp; head
  make: Entering directory '/var/home/acme/git/perf/tools/perf'
    BUILD:   Doing 'make -j32' parallel build
    HOSTCC  /tmp/build/perf/fixdep.o
    HOSTLD  /tmp/build/perf/fixdep-in.o
    LINK    /tmp/build/perf/fixdep

  Auto-detecting system features:
  ...                         dwarf: [ on  ]
  ...            dwarf_getlocations: [ on  ]
  ...                         glibc: [ on  ]
  $ ldd ~/bin/perf | grep python
	libpython3.9.so.1.0 =&gt; /lib64/libpython3.9.so.1.0 (0x00007f58800b0000)
  $ cat /tmp/build/perf/feature/test-all.make.output
  $

Reviewed-by: James Clark &lt;james.clark@arm.com&gt;
Fixes: 66dfdff03d196e51 ("perf tools: Add Python 3 support")
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Jaroslav Škarvada &lt;jskarvad@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lore.kernel.org/lkml/YaYmeeC6CS2b8OSz@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf tools: Enable libtracefs dynamic linking</title>
<updated>2021-09-28T19:08:37+00:00</updated>
<author>
<name>Ian Rogers</name>
<email>irogers@google.com</email>
</author>
<published>2021-09-23T00:10:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=b758a61b391fb5ed749f4848f444d8223ae0a324'/>
<id>urn:sha1:b758a61b391fb5ed749f4848f444d8223ae0a324</id>
<content type='text'>
Currently libtracefs isn't used by perf, but there are potential
improvements by using it as identified Steven Rostedt's e-mail:
https://lore.kernel.org/lkml/20210610154759.1ef958f0@oasis.local.home/

This change is modelled on the dynamic libtraceevent patch by Michael
Petlan:

https://lore.kernel.org/linux-perf-users/20210428092023.4009-1-mpetlan@redhat.com/

v3. Adds file missed in v1 and v2 spotted by Jiri Olsa.

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Cc: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Cc: Tzvetomir Stoyanov (VMware) &lt;tz.stoyanov@gmail.com&gt;
Cc: linux-trace-devel@vger.kernel.org
Link: http://lore.kernel.org/lkml/20210923001024.550263-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>tools: Remove feature-sync-compare-and-swap feature detection</title>
<updated>2021-08-09T20:02:02+00:00</updated>
<author>
<name>Leo Yan</name>
<email>leo.yan@linaro.org</email>
</author>
<published>2021-08-09T11:14:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=60fa754b2a5a4e0c44669f8d926a5a980c50b1e8'/>
<id>urn:sha1:60fa754b2a5a4e0c44669f8d926a5a980c50b1e8</id>
<content type='text'>
Since the __sync functions have been removed from perf, it's needless
for perf tool to test the feature sync-compare-and-swap.

The feature test is not used by any other components, remove it.

Signed-off-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Alexei Starovoitov &lt;ast@kernel.org&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Andrii Nakryiko &lt;andriin@fb.com&gt;
Cc: Borislav Petkov &lt;bp@alien8.de&gt;
Cc: Daniel Díaz &lt;daniel.diaz@linaro.org&gt;
Cc: Frank Ch. Eigler &lt;fche@redhat.com&gt;
Cc: H. Peter Anvin &lt;hpa@zytor.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Cc: Michael Petlan &lt;mpetlan@redhat.com&gt;
Cc: Mike Leach &lt;mike.leach@linaro.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Sedat Dilek &lt;sedat.dilek@gmail.com&gt;
Cc: Song Liu &lt;songliubraving@fb.com&gt;
Cc: Suzuki Poulouse &lt;suzuki.poulose@arm.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: coresight@lists.linaro.org
Cc: x86@kernel.org
Link: http://lore.kernel.org/lkml/20210809111407.596077-10-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>tools build: Allow deferring printing the results of feature detection</title>
<updated>2021-04-29T13:31:00+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2021-04-26T20:01:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=19177bc3da7e52bc7fb7e603556f98f06e074092'/>
<id>urn:sha1:19177bc3da7e52bc7fb7e603556f98f06e074092</id>
<content type='text'>
By setting FEATURE_DISPLAY_DEFERRED=1 a tool may ask for the printout
of the detected features in tools/build/Makefile.feature to be done
later adter extra feature checks are done that are tool specific.

The perf tool will do it via its tools/perf/Makefile.config, as it
performs such extra feature checks.

Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>perf tools: Enable libtraceevent dynamic linking</title>
<updated>2021-04-29T13:31:00+00:00</updated>
<author>
<name>Michael Petlan</name>
<email>mpetlan@redhat.com</email>
</author>
<published>2021-04-28T09:20:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=56d32d4cac645bac05fa70d935fa5040e3ab6bb3'/>
<id>urn:sha1:56d32d4cac645bac05fa70d935fa5040e3ab6bb3</id>
<content type='text'>
Currently we support only static linking with kernel's libtraceevent
(tools/lib/traceevent). This patch adds libtraceevent package detection
and support to link perf with it dynamically.

  The libtraceevent package status is displayed with:
  $ make VF=1 LIBTRACEEVENT_DYNAMIC=1
  ...
  ...                 libtraceevent: [ on  ]

Default behavior remains the same (static linking).

Committer testing:

  $ make LIBTRACEEVENT_DYNAMIC=1 VF=1 O=/tmp/build/perf -C tools/perf install-bin |&amp; grep traceevent
  Makefile.config:1090: *** Error: No libtraceevent devel library found, please install libtraceevent-devel.  Stop.
  $

Signed-off-by: Michael Petlan &lt;mpetlan@redhat.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
LPU-Reference: 20210428092023.4009-1-mpetlan@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
</feed>
