<feed xmlns='http://www.w3.org/2005/Atom'>
<title>user/sven/linux.git/tools/include, branch v6.7.9</title>
<subtitle>Linux Kernel
</subtitle>
<id>https://git.stealer.net/cgit.cgi/user/sven/linux.git/atom?h=v6.7.9</id>
<link rel='self' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/atom?h=v6.7.9'/>
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<updated>2024-02-23T08:51:20Z</updated>
<entry>
<title>work around gcc bugs with 'asm goto' with outputs</title>
<updated>2024-02-23T08:51:20Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-02-09T20:39:31Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=1bfa8bc86cc788c9c30430f52011c06f11abccd0'/>
<id>urn:sha1:1bfa8bc86cc788c9c30430f52011c06f11abccd0</id>
<content type='text'>
commit 4356e9f841f7fbb945521cef3577ba394c65f3fc upstream.

We've had issues with gcc and 'asm goto' before, and we created a
'asm_volatile_goto()' macro for that in the past: see commits
3f0116c3238a ("compiler/gcc4: Add quirk for 'asm goto' miscompilation
bug") and a9f180345f53 ("compiler/gcc4: Make quirk for
asm_volatile_goto() unconditional").

Then, much later, we ended up removing the workaround in commit
43c249ea0b1e ("compiler-gcc.h: remove ancient workaround for gcc PR
58670") because we no longer supported building the kernel with the
affected gcc versions, but we left the macro uses around.

Now, Sean Christopherson reports a new version of a very similar
problem, which is fixed by re-applying that ancient workaround.  But the
problem in question is limited to only the 'asm goto with outputs'
cases, so instead of re-introducing the old workaround as-is, let's
rename and limit the workaround to just that much less common case.

It looks like there are at least two separate issues that all hit in
this area:

 (a) some versions of gcc don't mark the asm goto as 'volatile' when it
     has outputs:

        https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98619
        https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110420

     which is easy to work around by just adding the 'volatile' by hand.

 (b) Internal compiler errors:

        https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110422

     which are worked around by adding the extra empty 'asm' as a
     barrier, as in the original workaround.

but the problem Sean sees may be a third thing since it involves bad
code generation (not an ICE) even with the manually added 'volatile'.

but the same old workaround works for this case, even if this feels a
bit like voodoo programming and may only be hiding the issue.

Reported-and-tested-by: Sean Christopherson &lt;seanjc@google.com&gt;
Link: https://lore.kernel.org/all/20240208220604.140859-1-seanjc@google.com/
Cc: Nick Desaulniers &lt;ndesaulniers@google.com&gt;
Cc: Uros Bizjak &lt;ubizjak@gmail.com&gt;
Cc: Jakub Jelinek &lt;jakub@redhat.com&gt;
Cc: Andrew Pinski &lt;quic_apinski@quicinc.com&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>bpf: Add crosstask check to __bpf_get_stack</title>
<updated>2024-01-25T23:44:45Z</updated>
<author>
<name>Jordan Rome</name>
<email>jordalgo@meta.com</email>
</author>
<published>2023-11-08T11:23:34Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=49c4d6fe853749e5e1be539b9f5834be1d0e34c4'/>
<id>urn:sha1:49c4d6fe853749e5e1be539b9f5834be1d0e34c4</id>
<content type='text'>
[ Upstream commit b8e3a87a627b575896e448021e5c2f8a3bc19931 ]

Currently get_perf_callchain only supports user stack walking for
the current task. Passing the correct *crosstask* param will return
0 frames if the task passed to __bpf_get_stack isn't the current
one instead of a single incorrect frame/address. This change
passes the correct *crosstask* param but also does a preemptive
check in __bpf_get_stack if the task is current and returns
-EOPNOTSUPP if it is not.

This issue was found using bpf_get_task_stack inside a BPF
iterator ("iter/task"), which iterates over all tasks.
bpf_get_task_stack works fine for fetching kernel stacks
but because get_perf_callchain relies on the caller to know
if the requested *task* is the current one (via *crosstask*)
it was failing in a confusing way.

It might be possible to get user stacks for all tasks utilizing
something like access_process_vm but that requires the bpf
program calling bpf_get_task_stack to be sleepable and would
therefore be a breaking change.

Fixes: fa28dcb82a38 ("bpf: Introduce helper bpf_get_task_stack()")
Signed-off-by: Jordan Rome &lt;jordalgo@meta.com&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20231108112334.3433136-1-jordalgo@meta.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>tools: Disable __packed attribute compiler warning due to -Werror=attributes</title>
<updated>2023-11-22T20:23:27Z</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2023-11-09T19:34:09Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=57686a72da08ae555d93148aa8756b16417a6aff'/>
<id>urn:sha1:57686a72da08ae555d93148aa8756b16417a6aff</id>
<content type='text'>
Noticed on several perf tools cross build test containers:

  [perfbuilder@five ~]$ grep FAIL ~/dm.log/summary
    19    10.18 debian:experimental-x-mips    : FAIL gcc version 12.3.0 (Debian 12.3.0-6)
    20    11.21 debian:experimental-x-mips64  : FAIL gcc version 12.3.0 (Debian 12.3.0-6)
    21    11.30 debian:experimental-x-mipsel  : FAIL gcc version 12.3.0 (Debian 12.3.0-6)
    37    12.07 ubuntu:18.04-x-arm            : FAIL gcc version 7.5.0 (Ubuntu/Linaro 7.5.0-3ubuntu1~18.04)
    42    11.91 ubuntu:18.04-x-riscv64        : FAIL gcc version 7.5.0 (Ubuntu 7.5.0-3ubuntu1~18.04)
    44    13.17 ubuntu:18.04-x-sh4            : FAIL gcc version 7.5.0 (Ubuntu 7.5.0-3ubuntu1~18.04)
    45    12.09 ubuntu:18.04-x-sparc64        : FAIL gcc version 7.5.0 (Ubuntu 7.5.0-3ubuntu1~18.04)
  [perfbuilder@five ~]$

  In file included from util/intel-pt-decoder/intel-pt-pkt-decoder.c:10:
  /tmp/perf-6.6.0-rc1/tools/include/asm-generic/unaligned.h: In function 'get_unaligned_le16':
  /tmp/perf-6.6.0-rc1/tools/include/asm-generic/unaligned.h:13:29: error: packed attribute causes inefficient alignment for 'x' [-Werror=attributes]
     13 |         const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr);      \
        |                             ^
  /tmp/perf-6.6.0-rc1/tools/include/asm-generic/unaligned.h:27:28: note: in expansion of macro '__get_unaligned_t'
     27 |         return le16_to_cpu(__get_unaligned_t(__le16, p));
        |                            ^~~~~~~~~~~~~~~~~

This comes from the kernel, where the -Wattributes and -Wpacked isn't
used, -Wpacked is already disabled, do it for the attributes as well.

Fixes: a91c987254651443 ("perf tools: Add get_unaligned_leNN()")
Suggested-by: 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/lkml/7c5b626c-1de9-4c12-a781-e44985b4a797@intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
</content>
</entry>
<entry>
<title>tools headers UAPI: Update tools's copy of unistd.h header</title>
<updated>2023-11-22T18:57:46Z</updated>
<author>
<name>Namhyung Kim</name>
<email>namhyung@kernel.org</email>
</author>
<published>2023-11-21T22:56:41Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=91c97b36bd6939a5c3c29de9e83e6359146c6939'/>
<id>urn:sha1:91c97b36bd6939a5c3c29de9e83e6359146c6939</id>
<content type='text'>
tldr; Just FYI, I'm carrying this on the perf tools tree.

Full explanation:

There used to be no copies, with tools/ code using kernel headers
directly. From time to time tools/perf/ broke due to legitimate kernel
hacking. At some point Linus complained about such direct usage. Then we
adopted the current model.

The way these headers are used in perf are not restricted to just
including them to compile something.

There are sometimes used in scripts that convert defines into string
tables, etc, so some change may break one of these scripts, or new MSRs
may use some different #define pattern, etc.

E.g.:

  $ ls -1 tools/perf/trace/beauty/*.sh | head -5
  tools/perf/trace/beauty/arch_errno_names.sh
  tools/perf/trace/beauty/drm_ioctl.sh
  tools/perf/trace/beauty/fadvise.sh
  tools/perf/trace/beauty/fsconfig.sh
  tools/perf/trace/beauty/fsmount.sh
  $
  $ tools/perf/trace/beauty/fadvise.sh
  static const char *fadvise_advices[] = {
        [0] = "NORMAL",
        [1] = "RANDOM",
        [2] = "SEQUENTIAL",
        [3] = "WILLNEED",
        [4] = "DONTNEED",
        [5] = "NOREUSE",
  };
  $

The tools/perf/check-headers.sh script, part of the tools/ build
process, points out changes in the original files.

So its important not to touch the copies in tools/ when doing changes in
the original kernel headers, that will be done later, when
check-headers.sh inform about the change to the perf tools hackers.

Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: linux-arch@vger.kernel.org
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lore.kernel.org/r/20231121225650.390246-6-namhyung@kernel.org
</content>
</entry>
<entry>
<title>tools headers UAPI: Update tools's copy of vhost.h header</title>
<updated>2023-11-22T18:57:46Z</updated>
<author>
<name>Namhyung Kim</name>
<email>namhyung@kernel.org</email>
</author>
<published>2023-11-21T22:56:40Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=daa97513415525e4d17c4978f3c47a7b7e935b36'/>
<id>urn:sha1:daa97513415525e4d17c4978f3c47a7b7e935b36</id>
<content type='text'>
tldr; Just FYI, I'm carrying this on the perf tools tree.

Full explanation:

There used to be no copies, with tools/ code using kernel headers
directly. From time to time tools/perf/ broke due to legitimate kernel
hacking. At some point Linus complained about such direct usage. Then we
adopted the current model.

The way these headers are used in perf are not restricted to just
including them to compile something.

There are sometimes used in scripts that convert defines into string
tables, etc, so some change may break one of these scripts, or new MSRs
may use some different #define pattern, etc.

E.g.:

  $ ls -1 tools/perf/trace/beauty/*.sh | head -5
  tools/perf/trace/beauty/arch_errno_names.sh
  tools/perf/trace/beauty/drm_ioctl.sh
  tools/perf/trace/beauty/fadvise.sh
  tools/perf/trace/beauty/fsconfig.sh
  tools/perf/trace/beauty/fsmount.sh
  $
  $ tools/perf/trace/beauty/fadvise.sh
  static const char *fadvise_advices[] = {
        [0] = "NORMAL",
        [1] = "RANDOM",
        [2] = "SEQUENTIAL",
        [3] = "WILLNEED",
        [4] = "DONTNEED",
        [5] = "NOREUSE",
  };
  $

The tools/perf/check-headers.sh script, part of the tools/ build
process, points out changes in the original files.

So its important not to touch the copies in tools/ when doing changes in
the original kernel headers, that will be done later, when
check-headers.sh inform about the change to the perf tools hackers.

Cc: "Michael S. Tsirkin" &lt;mst@redhat.com&gt;
Cc: Jason Wang &lt;jasowang@redhat.com&gt;
Cc: kvm@vger.kernel.org
Cc: virtualization@lists.linux.dev
Cc: netdev@vger.kernel.org
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lore.kernel.org/r/20231121225650.390246-5-namhyung@kernel.org
</content>
</entry>
<entry>
<title>tools headers UAPI: Update tools's copy of mount.h header</title>
<updated>2023-11-22T18:57:46Z</updated>
<author>
<name>Namhyung Kim</name>
<email>namhyung@kernel.org</email>
</author>
<published>2023-11-21T22:56:39Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=fb3648a6a87b674540f0ba7701a353006c408065'/>
<id>urn:sha1:fb3648a6a87b674540f0ba7701a353006c408065</id>
<content type='text'>
tldr; Just FYI, I'm carrying this on the perf tools tree.

Full explanation:

There used to be no copies, with tools/ code using kernel headers
directly. From time to time tools/perf/ broke due to legitimate kernel
hacking. At some point Linus complained about such direct usage. Then we
adopted the current model.

The way these headers are used in perf are not restricted to just
including them to compile something.

There are sometimes used in scripts that convert defines into string
tables, etc, so some change may break one of these scripts, or new MSRs
may use some different #define pattern, etc.

E.g.:

  $ ls -1 tools/perf/trace/beauty/*.sh | head -5
  tools/perf/trace/beauty/arch_errno_names.sh
  tools/perf/trace/beauty/drm_ioctl.sh
  tools/perf/trace/beauty/fadvise.sh
  tools/perf/trace/beauty/fsconfig.sh
  tools/perf/trace/beauty/fsmount.sh
  $
  $ tools/perf/trace/beauty/fadvise.sh
  static const char *fadvise_advices[] = {
        [0] = "NORMAL",
        [1] = "RANDOM",
        [2] = "SEQUENTIAL",
        [3] = "WILLNEED",
        [4] = "DONTNEED",
        [5] = "NOREUSE",
  };
  $

The tools/perf/check-headers.sh script, part of the tools/ build
process, points out changes in the original files.

So its important not to touch the copies in tools/ when doing changes in
the original kernel headers, that will be done later, when
check-headers.sh inform about the change to the perf tools hackers.

Cc: Alexander Viro &lt;viro@zeniv.linux.org.uk&gt;
Cc: Christian Brauner &lt;brauner@kernel.org&gt;
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lore.kernel.org/r/20231121225650.390246-4-namhyung@kernel.org
</content>
</entry>
<entry>
<title>tools headers UAPI: Update tools's copy of kvm.h header</title>
<updated>2023-11-22T18:57:46Z</updated>
<author>
<name>Namhyung Kim</name>
<email>namhyung@kernel.org</email>
</author>
<published>2023-11-21T22:56:38Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=5a9f95b67059dda160f65ab41c48587103b3b3a0'/>
<id>urn:sha1:5a9f95b67059dda160f65ab41c48587103b3b3a0</id>
<content type='text'>
tldr; Just FYI, I'm carrying this on the perf tools tree.

Full explanation:

There used to be no copies, with tools/ code using kernel headers
directly. From time to time tools/perf/ broke due to legitimate kernel
hacking. At some point Linus complained about such direct usage. Then we
adopted the current model.

The way these headers are used in perf are not restricted to just
including them to compile something.

There are sometimes used in scripts that convert defines into string
tables, etc, so some change may break one of these scripts, or new MSRs
may use some different #define pattern, etc.

E.g.:

  $ ls -1 tools/perf/trace/beauty/*.sh | head -5
  tools/perf/trace/beauty/arch_errno_names.sh
  tools/perf/trace/beauty/drm_ioctl.sh
  tools/perf/trace/beauty/fadvise.sh
  tools/perf/trace/beauty/fsconfig.sh
  tools/perf/trace/beauty/fsmount.sh
  $
  $ tools/perf/trace/beauty/fadvise.sh
  static const char *fadvise_advices[] = {
        [0] = "NORMAL",
        [1] = "RANDOM",
        [2] = "SEQUENTIAL",
        [3] = "WILLNEED",
        [4] = "DONTNEED",
        [5] = "NOREUSE",
  };
  $

The tools/perf/check-headers.sh script, part of the tools/ build
process, points out changes in the original files.

So its important not to touch the copies in tools/ when doing changes in
the original kernel headers, that will be done later, when
check-headers.sh inform about the change to the perf tools hackers.

Cc: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Cc: kvm@vger.kernel.org
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lore.kernel.org/r/20231121225650.390246-3-namhyung@kernel.org
</content>
</entry>
<entry>
<title>tools headers UAPI: Update tools's copy of fscrypt.h header</title>
<updated>2023-11-22T18:57:46Z</updated>
<author>
<name>Namhyung Kim</name>
<email>namhyung@kernel.org</email>
</author>
<published>2023-11-21T22:56:37Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=111844666672347747585e24d6cebda640bd1284'/>
<id>urn:sha1:111844666672347747585e24d6cebda640bd1284</id>
<content type='text'>
tldr; Just FYI, I'm carrying this on the perf tools tree.

Full explanation:

There used to be no copies, with tools/ code using kernel headers
directly. From time to time tools/perf/ broke due to legitimate kernel
hacking. At some point Linus complained about such direct usage. Then we
adopted the current model.

The way these headers are used in perf are not restricted to just
including them to compile something.

There are sometimes used in scripts that convert defines into string
tables, etc, so some change may break one of these scripts, or new MSRs
may use some different #define pattern, etc.

E.g.:

  $ ls -1 tools/perf/trace/beauty/*.sh | head -5
  tools/perf/trace/beauty/arch_errno_names.sh
  tools/perf/trace/beauty/drm_ioctl.sh
  tools/perf/trace/beauty/fadvise.sh
  tools/perf/trace/beauty/fsconfig.sh
  tools/perf/trace/beauty/fsmount.sh
  $
  $ tools/perf/trace/beauty/fadvise.sh
  static const char *fadvise_advices[] = {
        [0] = "NORMAL",
        [1] = "RANDOM",
        [2] = "SEQUENTIAL",
        [3] = "WILLNEED",
        [4] = "DONTNEED",
        [5] = "NOREUSE",
  };
  $

The tools/perf/check-headers.sh script, part of the tools/ build
process, points out changes in the original files.

So its important not to touch the copies in tools/ when doing changes in
the original kernel headers, that will be done later, when
check-headers.sh inform about the change to the perf tools hackers.

Cc: Eric Biggers &lt;ebiggers@kernel.org&gt;
Cc: "Theodore Y. Ts'o" &lt;tytso@mit.edu&gt;
Cc: Jaegeuk Kim &lt;jaegeuk@kernel.org&gt;
Cc: linux-fscrypt@vger.kernel.org
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lore.kernel.org/r/20231121225650.390246-2-namhyung@kernel.org
</content>
</entry>
<entry>
<title>tools headers UAPI: Update tools's copy of drm headers</title>
<updated>2023-11-22T18:57:46Z</updated>
<author>
<name>Namhyung Kim</name>
<email>namhyung@kernel.org</email>
</author>
<published>2023-11-21T22:56:36Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=1041dfe6109fcb24e9a3d5d4ca9218e64dc0ed29'/>
<id>urn:sha1:1041dfe6109fcb24e9a3d5d4ca9218e64dc0ed29</id>
<content type='text'>
tldr; Just FYI, I'm carrying this on the perf tools tree.

Full explanation:

There used to be no copies, with tools/ code using kernel headers
directly. From time to time tools/perf/ broke due to legitimate kernel
hacking. At some point Linus complained about such direct usage. Then we
adopted the current model.

The way these headers are used in perf are not restricted to just
including them to compile something.

There are sometimes used in scripts that convert defines into string
tables, etc, so some change may break one of these scripts, or new MSRs
may use some different #define pattern, etc.

E.g.:

  $ ls -1 tools/perf/trace/beauty/*.sh | head -5
  tools/perf/trace/beauty/arch_errno_names.sh
  tools/perf/trace/beauty/drm_ioctl.sh
  tools/perf/trace/beauty/fadvise.sh
  tools/perf/trace/beauty/fsconfig.sh
  tools/perf/trace/beauty/fsmount.sh
  $
  $ tools/perf/trace/beauty/fadvise.sh
  static const char *fadvise_advices[] = {
        [0] = "NORMAL",
        [1] = "RANDOM",
        [2] = "SEQUENTIAL",
        [3] = "WILLNEED",
        [4] = "DONTNEED",
        [5] = "NOREUSE",
  };
  $

The tools/perf/check-headers.sh script, part of the tools/ build
process, points out changes in the original files.

So its important not to touch the copies in tools/ when doing changes in
the original kernel headers, that will be done later, when
check-headers.sh inform about the change to the perf tools hackers.

Cc: David Airlie &lt;airlied@gmail.com&gt;
Cc: Daniel Vetter &lt;daniel@ffwll.ch&gt;
Cc: Maarten Lankhorst &lt;maarten.lankhorst@linux.intel.com&gt;
Cc: Maxime Ripard &lt;mripard@kernel.org&gt;
Cc: Thomas Zimmermann &lt;tzimmermann@suse.de&gt;
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lore.kernel.org/r/20231121225650.390246-1-namhyung@kernel.org
</content>
</entry>
<entry>
<title>Merge tag 'perf-tools-for-v6.7-1-2023-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools</title>
<updated>2023-11-03T18:17:38Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-11-03T18:17:38Z</published>
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<content type='text'>
Pull perf tools updates from Namhyung Kim:
 "Build:

   - Compile BPF programs by default if clang (&gt;= 12.0.1) is available
     to enable more features like kernel lock contention, off-cpu
     profiling, kwork, sample filtering and so on.

     This can be disabled by passing BUILD_BPF_SKEL=0 to make.

   - Produce better error messages for bison on debug build (make
     DEBUG=1) by defining YYDEBUG symbol internally.

  perf record:

   - Track sideband events (like FORK/MMAP) from all CPUs even if perf
     record targets a subset of CPUs only (using -C option). Otherwise
     it may lose some information happened on a CPU out of the target
     list.

   - Fix checking raw sched_switch tracepoint argument using system BTF.
     This affects off-cpu profiling which attaches a BPF program to the
     raw tracepoint.

  perf lock contention:

   - Add --lock-cgroup option to see contention by cgroups. This should
     be used with BPF only (using -b option).

       $ sudo perf lock con -ab --lock-cgroup -- sleep 1
        contended   total wait     max wait     avg wait   cgroup

              835     14.06 ms     41.19 us     16.83 us   /system.slice/led.service
               25    122.38 us     13.77 us      4.89 us   /
               44     23.73 us      3.87 us       539 ns   /user.slice/user-657345.slice/session-c4.scope
                1       491 ns       491 ns       491 ns   /system.slice/connectd.service

   - Add -G/--cgroup-filter option to see contention only for given
     cgroups.

     This can be useful when you identified a cgroup in the above
     command and want to investigate more on it. It also works with
     other output options like -t/--threads and -l/--lock-addr.

       $ sudo perf lock con -ab -G /user.slice/user-657345.slice/session-c4.scope -- sleep 1
        contended   total wait     max wait     avg wait         type   caller

                8     77.11 us     17.98 us      9.64 us     spinlock   futex_wake+0xc8
                2     24.56 us     14.66 us     12.28 us     spinlock   tick_do_update_jiffies64+0x25
                1      4.97 us      4.97 us      4.97 us     spinlock   futex_q_lock+0x2a

   - Use per-cpu array for better spinlock tracking. This is to improve
     performance of the BPF program and to avoid nested contention on a
     lock in the BPF hash map.

   - Update callstack check for PowerPC. To find a representative caller
     of a lock, it needs to look up the call stacks. It ends the lookup
     when it sees 0 in the call stack buffer. However, PowerPC call
     stacks can have 0 values in the beginning so skip them when it
     expects valid call stacks after.

  perf kwork:

   - Support 'sched' class (for -k option) so that it can see task
     scheduling event (using sched_switch tracepoint) as well as irq and
     workqueue items.

   - Add perf kwork top subcommand to show more accurate cpu utilization
     with sched class above. It works both with a recorded data (using
     perf kwork record command) and BPF (using -b option). Unlike perf
     top command, it does not support interactive mode (yet).

       $ sudo perf kwork top -b -k sched
       Starting trace, Hit &lt;Ctrl+C&gt; to stop and report
       ^C
       Total  : 160702.425 ms, 8 cpus
       %Cpu(s):  36.00% id,   0.00% hi,   0.00% si
       %Cpu0   [||||||||||||||||||              61.66%]
       %Cpu1   [||||||||||||||||||              61.27%]
       %Cpu2   [|||||||||||||||||||             66.40%]
       %Cpu3   [||||||||||||||||||              61.28%]
       %Cpu4   [||||||||||||||||||              61.82%]
       %Cpu5   [|||||||||||||||||||||||         77.41%]
       %Cpu6   [||||||||||||||||||              61.73%]
       %Cpu7   [||||||||||||||||||              63.25%]

             PID     SPID    %CPU           RUNTIME  COMMMAND
         -------------------------------------------------------------
               0        0   38.72       8089.463 ms  [swapper/1]
               0        0   38.71       8084.547 ms  [swapper/3]
               0        0   38.33       8007.532 ms  [swapper/0]
               0        0   38.26       7992.985 ms  [swapper/6]
               0        0   38.17       7971.865 ms  [swapper/4]
               0        0   36.74       7447.765 ms  [swapper/7]
               0        0   33.59       6486.942 ms  [swapper/2]
               0        0   22.58       3771.268 ms  [swapper/5]
            9545     9351    2.48        447.136 ms  sched-messaging
            9574     9351    2.09        418.583 ms  sched-messaging
            9724     9351    2.05        372.407 ms  sched-messaging
            9531     9351    2.01        368.804 ms  sched-messaging
            9512     9351    2.00        362.250 ms  sched-messaging
            9514     9351    1.95        357.767 ms  sched-messaging
            9538     9351    1.86        384.476 ms  sched-messaging
            9712     9351    1.84        386.490 ms  sched-messaging
            9723     9351    1.83        380.021 ms  sched-messaging
            9722     9351    1.82        382.738 ms  sched-messaging
            9517     9351    1.81        354.794 ms  sched-messaging
            9559     9351    1.79        344.305 ms  sched-messaging
            9725     9351    1.77        365.315 ms  sched-messaging
       &lt;SNIP&gt;

   - Add hard/soft-irq statistics to perf kwork top. This will show the
     total CPU utilization with IRQ stats like below:

       $ sudo perf kwork top -b -k sched,irq,softirq
       Starting trace, Hit &lt;Ctrl+C&gt; to stop and report
       ^C
       Total  :  12554.889 ms, 8 cpus
       %Cpu(s):  96.23% id,   0.10% hi,   0.19% si      &lt;---- here
       %Cpu0   [|                                4.60%]
       %Cpu1   [|                                4.59%]
       %Cpu2   [                                 2.73%]
       %Cpu3   [|                                3.81%]
       &lt;SNIP&gt;

  perf bench:

   - Add -G/--cgroups option to perf bench sched pipe. The pipe bench is
     good to measure context switch overhead. With this option, it puts
     the reader and writer tasks in separate cgroups to enforce context
     switch between two different cgroups.

     Also it needs to set CPU affinity of the tasks in a CPU to
     accurately measure the impact of cgroup context switches.

       $ sudo perf stat -e context-switches,cgroup-switches -- \
       &gt; taskset -c 0 perf bench sched pipe -l 100000
       # Running 'sched/pipe' benchmark:
       # Executed 100000 pipe operations between two processes

            Total time: 0.307 [sec]

              3.078180 usecs/op
                324867 ops/sec

        Performance counter stats for 'taskset -c 0 perf bench sched pipe -l 100000':

                  200,026      context-switches
                       63      cgroup-switches

              0.321637922 seconds time elapsed

     You can see small number of cgroup-switches because both write and
     read tasks are in the same cgroup.

       $ sudo mkdir /sys/fs/cgroup/{AAA,BBB}

       $ sudo perf stat -e context-switches,cgroup-switches -- \
       &gt; taskset -c 0 perf bench sched pipe -l 100000 -G AAA,BBB
       # Running 'sched/pipe' benchmark:
       # Executed 100000 pipe operations between two processes

            Total time: 0.351 [sec]

              3.512990 usecs/op
                284657 ops/sec

        Performance counter stats for 'taskset -c 0 perf bench sched pipe -l 100000 -G AAA,BBB':

                  200,020      context-switches
                  200,019      cgroup-switches

              0.365034567 seconds time elapsed

     Now context-switches and cgroup-switches are almost same. And you
     can see the pipe operation took little more.

   - Kill child processes when perf bench sched messaging exited
     abnormally. Otherwise it'd leave the child doing unnecessary work.

  perf test:

   - Fix various shellcheck issues on the tests written in shell script.

   - Skip tests when condition is not satisfied:
      - object code reading test for non-text section addresses.
      - CoreSight test if cs_etm// event is not available.
      - lock contention test if not enough CPUs.

  Event parsing:

   - Make PMU alias name loading lazy to reduce the startup time in the
     event parsing code for perf record, stat and others in the general
     case.

   - Lazily compute PMU default config. In the same sense, delay PMU
     initialization until it's really needed to reduce the startup cost.

   - Fix event term values that are raw events. The event specification
     can have several terms including event name. But sometimes it
     clashes with raw event encoding which starts with 'r' and has
     hex-digits.

     For example, an event named 'read' should be processed as a normal
     event but it was mis-treated as a raw encoding and caused a
     failure.

       $ perf stat -e 'uncore_imc_free_running/event=read/' -a sleep 1
       event syntax error: '..nning/event=read/'
                                         \___ parser error
       Run 'perf list' for a list of valid events

        Usage: perf stat [&lt;options&gt;] [&lt;command&gt;]

           -e, --event &lt;event&gt; event selector. use 'perf list' to list available events

  Event metrics:

   - Add "Compat" regex to match event with multiple identifiers.

   - Usual updates for Intel, Power10, Arm telemetry/CMN and AmpereOne.

  Misc:

   - Assorted memory leak fixes and footprint reduction.

   - Add "bpf_skeletons" to perf version --build-options so that users
     can check whether their perf tools have BPF support easily.

   - Fix unaligned access in Intel-PT packet decoder found by
     undefined-behavior sanitizer.

   - Avoid frequency mode for the dummy event. Surprisingly it'd impact
     kernel timer tick handler performance by force iterating all PMU
     events.

   - Update bash shell completion for events and metrics"

* tag 'perf-tools-for-v6.7-1-2023-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (187 commits)
  perf vendor events intel: Update tsx_cycles_per_elision metrics
  perf vendor events intel: Update bonnell version number to v5
  perf vendor events intel: Update westmereex events to v4
  perf vendor events intel: Update meteorlake events to v1.06
  perf vendor events intel: Update knightslanding events to v16
  perf vendor events intel: Add typo fix for ivybridge FP
  perf vendor events intel: Update a spelling in haswell/haswellx
  perf vendor events intel: Update emeraldrapids to v1.01
  perf vendor events intel: Update alderlake/alderlake events to v1.23
  perf build: Disable BPF skeletons if clang version is &lt; 12.0.1
  perf callchain: Fix spelling mistake "statisitcs" -&gt; "statistics"
  perf report: Fix spelling mistake "heirachy" -&gt; "hierarchy"
  perf python: Fix binding linkage due to rename and move of evsel__increase_rlimit()
  perf tests: test_arm_coresight: Simplify source iteration
  perf vendor events intel: Add tigerlake two metrics
  perf vendor events intel: Add broadwellde two metrics
  perf vendor events intel: Fix broadwellde tma_info_system_dram_bw_use metric
  perf mem_info: Add and use map_symbol__exit and addr_map_symbol__exit
  perf callchain: Minor layout changes to callchain_list
  perf callchain: Make brtype_stat in callchain_list optional
  ...
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