linux.git/tools/perf/tests/bpf.c, branch master

perf parse-events: Remove BPF event support

2023-08-15T19:41:48+00:00

New features like the BPF --filter support in perf record have made the
BPF event functionality somewhat redundant. As shown by commit
fcb027c1a4f6 ("perf tools: Revert enable indices setting syntax for BPF
map") and commit 14e4b9f4289a ("perf trace: Raw augmented syscalls fix
libbpf 1.0+ compatibility") the BPF event support hasn't been well
maintained and it adds considerable complexity in areas like event
parsing, not least as '/' is a separator for event modifiers as well as
in paths.

This patch removes support in the event parser for BPF events and then
the associated functions are removed. This leads to the removal of whole
source files like bpf-loader.c.  Removing support means that augmented
syscalls in perf trace is broken, this will be fixed in a later commit
adding support using BPF skeletons.

The removal of BPF events causes an unused label warning from flex
generated code, so update build to ignore it:

  ```
  util/parse-events-flex.c:2704:1: error: label ‘find_rule’ defined but not used [-Werror=unused-label]
  2704 | find_rule: /* we branch to this label when backing up */
  ```

Committer notes:

Extracted from a larger patch that was also removing the support for
linking with libllvm and libclang, that were an alternative to using an
external clang execution to compile the .c event source code into BPF
bytecode.

Testing it:

  # perf trace -e /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c
  event syntax error: '/home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c'
                        \___ Bad event or PMU

  Unabled to find PMU or event on a PMU of 'home'

  Initial error:
  event syntax error: '/home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c'
                        \___ Cannot find PMU `home'. Missing kernel support?
  Run 'perf list' for a list of valid events

   Usage: perf trace [] []
      or: perf trace [] --  []
      or: perf trace record [] []
      or: perf trace record [] --  []

      -e, --event    event/syscall selector. use 'perf list' to list available events
  #

Signed-off-by: Ian Rogers 
Acked-by: Jiri Olsa 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Andrii Nakryiko 
Cc: Anshuman Khandual 
Cc: Athira Rajeev 
Cc: Brendan Gregg 
Cc: Carsten Haitzler 
Cc: Eduard Zingerman 
Cc: Fangrui Song 
Cc: He Kuang 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Madhavan Srinivasan 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Nathan Chancellor 
Cc: Naveen N. Rao 
Cc: Nick Desaulniers 
Cc: Peter Zijlstra 
Cc: Ravi Bangoria 
Cc: Rob Herring 
Cc: Tiezhu Yang 
Cc: Tom Rix 
Cc: Wang Nan 
Cc: Wang ShaoBo 
Cc: Yang Jihong 
Cc: Yonghong Song 
Cc: YueHaibing 
Cc: bpf@vger.kernel.org
Cc: llvm@lists.linux.dev
Link: https://lore.kernel.org/r/20230810184853.2860737-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo 

Signed-off-by: Arnaldo Carvalho de Melo

perf test bpf: Address error about non-null argument for epoll_pwait 2nd arg

2023-08-03T20:01:27+00:00

First noticed on Fedora Rawhide:

  tests/bpf.c: In function ‘epoll_pwait_loop’:
  tests/bpf.c:36:17: error: argument 2 null where non-null expected [-Werror=nonnull]
     36 |                 epoll_pwait(-(i + 1), NULL, 0, 0, NULL);
        |                 ^~~~~~~~~~~
  In file included from tests/bpf.c:5:
  /usr/include/sys/epoll.h:134:12: note: in a call to function ‘epoll_pwait’ declared ‘nonnull’
    134 | extern int epoll_pwait (int __epfd, struct epoll_event *__events,
        |            ^~~~~~~~~~~

  [perfbuilder@27cfe44d67ed perf-6.5.0-rc2]$ gcc -v
  Using built-in specs.
  COLLECT_GCC=gcc
  COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-redhat-linux/13/lto-wrapper
  OFFLOAD_TARGET_NAMES=nvptx-none
  OFFLOAD_TARGET_DEFAULT=1
  Target: x86_64-redhat-linux
  Configured with: ../configure --enable-bootstrap --enable-languages=c,c++,fortran,objc,obj-c++,ada,go,d,m2,lto --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-shared --enable-threads=posix --enable-checking=release --enable-multilib --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-linker-build-id --with-gcc-major-version-only --enable-libstdcxx-backtrace --with-libstdcxx-zoneinfo=/usr/share/zoneinfo --with-linker-hash-style=gnu --enable-plugin --enable-initfini-array --with-isl=/builddir/build/BUILD/gcc-13.2.1-20230728/obj-x86_64-redhat-linux/isl-install --enable-offload-targets=nvptx-none --without-cuda-driver --enable-offload-defaulted --enable-gnu-indirect-function --enable-cet --with-tune=generic --with-arch_32=i686 --build=x86_64-redhat-linux --with-build-config=bootstrap-lto --enable-link-serialization=1
  Thread model: posix
  Supported LTO compression algorithms: zlib zstd
  gcc version 13.2.1 20230728 (Red Hat 13.2.1-1) (GCC)
  [perfbuilder@27cfe44d67ed perf-6.5.0-rc2]$

Just add that argument to address this compiler warning.

Cc: Adrian Hunter 
Cc: Ian Rogers 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: https://lore.kernel.org/lkml/ZMj8+bvN86D0ZKiB@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf parse-events: Populate error column for BPF/tracepoint events

2023-07-28T22:01:16+00:00

Follow convention from parse_events_terms__num/str and pass the
YYLTYPE for the location.

Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Athira Rajeev 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230627181030.95608-12-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

perf evlist: Remove nr_groups

2023-03-13T20:42:27+00:00

Maintaining the number of groups during event parsing is problematic
and since changing to sort/regroup events can only be computed by a
linear pass over the evlist. As the value is generally only used in
tests, rather than hold it in a variable compute it by passing over
the evlist when necessary.

This change highlights that libpfm's counting of groups with a single
entry disagreed with regular event parsing. The libpfm tests are
updated accordingly.

Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Florian Fischer 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: John Garry 
Cc: Kajol Jain 
Cc: Kan Liang 
Cc: Kim Phillips 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Ravi Bangoria 
Cc: Sean Christopherson 
Cc: Steinar H. Gunderson 
Cc: Stephane Eranian 
Cc: Suzuki Poulouse 
Cc: Xing Zhengjun 
Link: https://lore.kernel.org/r/20230312021543.3060328-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

perf test bpf: Skip test if kernel-debuginfo is not present

2023-02-06T18:01:23+00:00

Perf BPF filter test fails in environment where "kernel-debuginfo"
is not installed.

Test failure logs:

  <<>>
  42: BPF filter                            :
  42.1: Basic BPF filtering                 : Ok
  42.2: BPF pinning                         : Ok
  42.3: BPF prologue generation             : FAILED!
  <<>>

Enabling verbose option provided debug logs, which says debuginfo
needs to be installed. Snippet of verbose logs:

  <<>>
  42.3: BPF prologue generation                                       :
  --- start ---
  test child forked, pid 28218
  <<>>
  Rebuild with CONFIG_DEBUG_INFO=y, or install an appropriate debuginfo
  package.
  bpf_probe: failed to convert perf probe events
  Failed to add events selected by BPF
  test child finished with -1
  ---- end ----
  BPF filter subtest 3: FAILED!
  <<>>

Here the subtest "BPF prologue generation" failed and logs shows
debuginfo is needed. After installing kernel-debuginfo package, testcase
passes.

The "BPF prologue generation" subtest failed because, the do_test()
returns TEST_FAIL without checking the error type returned by
parse_events_load_bpf_obj().

parse_events_load_bpf_obj() can also return error of type -ENODATA
incase kernel-debuginfo package is not installed. Fix this by adding
check for -ENODATA error.

Test result after the patch changes:

Test failure logs:

  <<>>
  42: BPF filter                 :
  42.1: Basic BPF filtering      : Ok
  42.2: BPF pinning              : Ok
  42.3: BPF prologue generation  : Skip (clang/debuginfo isn't installed or environment missing BPF support)
  <<>>

Fixes: ba1fae431e74bb42 ("perf test: Add 'perf test BPF'")
Signed-off-by: Athira Rajeev 
Cc: Andi Kleen 
Cc: Disha Goel 
Cc: Ian Rogers 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: Kajol Jain 
Cc: Madhavan Srinivasan 
Cc: Michael Ellerman 
Cc: Nageswara R Sastry 
Cc: Namhyung Kim 
Cc: Wang Nan 
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lore.kernel.org/linux-perf-users/Y7bIk77mdE4j8Jyi@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf test bpf: Check for libtraceevent support

2023-02-06T14:40:59+00:00

The "bpf" tests fails in environment with missing libtraceevent support
as below:

  # ./perf test 36
  36: BPF filter                          :
  36.1: Basic BPF filtering               : FAILED!
  36.2: BPF pinning                       : FAILED!
  36.3: BPF prologue generation           : FAILED!

The environment has clang but missing the libtraceevent devel. Hence
perf is compiled without libtraceevent support.

Detailed logs:
	./perf test -v "Basic BPF filtering"

	Failed to add BPF event syscalls:sys_enter_epoll_pwait
	bpf: tracepoint call back failed, stop iterate
	Failed to add events selected by BPF

The bpf tests tris to add probe event which fails at
"parse_events_add_tracepoint" function due to missing libtraceevent. Add
check for "HAVE_LIBTRACEEVENT" in the "tests/bpf.c" before proceeding
with the test.

With the change,

	# ./perf test 36
 	36: BPF filter                    :
 	36.1: Basic BPF filtering         : Skip (not compiled in or missing libtraceevent support)
 	36.2: BPF pinning                 : Skip (not compiled in or missing libtraceevent support)
 	36.3: BPF prologue generation     : Skip (not compiled in or missing libtraceevent support)

Signed-off-by: Athira Jajeev 
Tested-by: Arnaldo Carvalho de Melo 
Tested-by: Disha Goel 
Cc: Andi Kleen 
Cc: Ian Rogers 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: Kajol Jain 
Cc: Madhavan Srinivasan 
Cc: Michael Ellerman 
Cc: Nageswara R Sastry 
Cc: Namhyung Kim 
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lore.kernel.org/r/20230131135001.54578-1-atrajeev@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf test bpf: Skip test if clang is not present

2022-05-21T17:54:21+00:00

Perf BPF filter test fails in environment where "clang" is not
installed.

Test failure logs:

<<>>
 42: BPF filter                    :
 42.1: Basic BPF filtering         : Skip
 42.2: BPF pinning                 : FAILED!
 42.3: BPF prologue generation     : FAILED!
<<>>

Enabling verbose option provided debug logs which says clang/llvm needs
to be installed. Snippet of verbose logs:

<<>>
 42.2: BPF pinning                  :
 --- start ---
test child forked, pid 61423
ERROR:	unable to find clang.
Hint:	Try to install latest clang/llvm to support BPF.
        Check your $PATH

<>

Failed to compile test case: 'Basic BPF llvm compile'
Unable to get BPF object, fix kbuild first
test child finished with -1
 ---- end ----
BPF filter subtest 2: FAILED!
<<>>

Here subtests, "BPF pinning" and "BPF prologue generation" failed and
logs shows clang/llvm is needed. After installing clang, testcase
passes.

Reason on why subtest failure happens though logs has proper debug
information:

Main function __test__bpf calls test_llvm__fetch_bpf_obj by
passing 4th argument as true ( 4th arguments maps to parameter
"force" in test_llvm__fetch_bpf_obj ). But this will cause
test_llvm__fetch_bpf_obj to skip the check for clang/llvm.

Snippet of code part which checks for clang based on
parameter "force" in test_llvm__fetch_bpf_obj:

<<>>
if (!force && (!llvm_param.user_set_param &&
<<>>

Since force is set to "false", test won't get skipped and fails to
compile test case. The BPF code compilation needs clang, So pass the
fourth argument as "false" and also skip the test if reason for return
is "TEST_SKIP"

After the patch:

<<>>
 42: BPF filter                    :
 42.1: Basic BPF filtering         : Skip
 42.2: BPF pinning                 : Skip
 42.3: BPF prologue generation     : Skip
<<>>

Fixes: ba1fae431e74bb42 ("perf test: Add 'perf test BPF'")
Reviewed-by: Kajol Jain 
Signed-off-by: Athira Jajeev 
Acked-by: Ian Rogers 
Cc: Disha Goel 
Cc: Jiri Olsa 
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Madhavan Srinivasan 
Cc: Michael Ellerman 
Cc: Nageswara R Sastry 
Cc: Wang Nan 
Link: https://lore.kernel.org/r/20220511115438.84032-1-atrajeev@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf bpf: Stop using deprecated bpf_load_program() API

2022-02-14T18:49:34+00:00

bpf_load_program() API is deprecated, remove perf's usage of the
deprecated function. Add a __weak function declaration for libbpf
version compatibility.

Signed-off-by: Christy Lee 
Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: Jiri Olsa 
Cc: bpf@vger.kernel.org
Cc: kernel-team@fb.com
Link: https://lore.kernel.org/bpf/20220212073054.1052880-2-andrii@kernel.org
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Arnaldo Carvalho de Melo

Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

2021-12-10T23:56:13+00:00

Andrii Nakryiko says:

====================
bpf-next 2021-12-10 v2

We've added 115 non-merge commits during the last 26 day(s) which contain
a total of 182 files changed, 5747 insertions(+), 2564 deletions(-).

The main changes are:

1) Various samples fixes, from Alexander Lobakin.

2) BPF CO-RE support in kernel and light skeleton, from Alexei Starovoitov.

3) A batch of new unified APIs for libbpf, logging improvements, version
   querying, etc. Also a batch of old deprecations for old APIs and various
   bug fixes, in preparation for libbpf 1.0, from Andrii Nakryiko.

4) BPF documentation reorganization and improvements, from Christoph Hellwig
   and Dave Tucker.

5) Support for declarative initialization of BPF_MAP_TYPE_PROG_ARRAY in
   libbpf, from Hengqi Chen.

6) Verifier log fixes, from Hou Tao.

7) Runtime-bounded loops support with bpf_loop() helper, from Joanne Koong.

8) Extend branch record capturing to all platforms that support it,
   from Kajol Jain.

9) Light skeleton codegen improvements, from Kumar Kartikeya Dwivedi.

10) bpftool doc-generating script improvements, from Quentin Monnet.

11) Two libbpf v0.6 bug fixes, from Shuyi Cheng and Vincent Minet.

12) Deprecation warning fix for perf/bpf_counter, from Song Liu.

13) MAX_TAIL_CALL_CNT unification and MIPS build fix for libbpf,
    from Tiezhu Yang.

14) BTF_KING_TYPE_TAG follow-up fixes, from Yonghong Song.

15) Selftests fixes and improvements, from Ilya Leoshkevich, Jean-Philippe
    Brucker, Jiri Olsa, Maxim Mikityanskiy, Tirthendu Sarkar, Yucong Sun,
    and others.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (115 commits)
  libbpf: Add "bool skipped" to struct bpf_map
  libbpf: Fix typo in btf__dedup@LIBBPF_0.0.2 definition
  bpftool: Switch bpf_object__load_xattr() to bpf_object__load()
  selftests/bpf: Remove the only use of deprecated bpf_object__load_xattr()
  selftests/bpf: Add test for libbpf's custom log_buf behavior
  selftests/bpf: Replace all uses of bpf_load_btf() with bpf_btf_load()
  libbpf: Deprecate bpf_object__load_xattr()
  libbpf: Add per-program log buffer setter and getter
  libbpf: Preserve kernel error code and remove kprobe prog type guessing
  libbpf: Improve logging around BPF program loading
  libbpf: Allow passing user log setting through bpf_object_open_opts
  libbpf: Allow passing preallocated log_buf when loading BTF into kernel
  libbpf: Add OPTS-based bpf_btf_load() API
  libbpf: Fix bpf_prog_load() log_buf logic for log_level 0
  samples/bpf: Remove unneeded variable
  bpf: Remove redundant assignment to pointer t
  selftests/bpf: Fix a compilation warning
  perf/bpf_counter: Use bpf_map_create instead of bpf_create_map
  samples: bpf: Fix 'unknown warning group' build warning on Clang
  samples: bpf: Fix xdp_sample_user.o linking with Clang
  ...
====================

Link: https://lore.kernel.org/r/20211210234746.2100561-1-andrii@kernel.org
Signed-off-by: Jakub Kicinski

perf: Mute libbpf API deprecations temporarily

2021-12-03T19:54:51+00:00

Libbpf development version was bumped to 0.7 in c93faaaf2f67
("libbpf: Deprecate bpf_prog_load_xattr() API"), activating a bunch of
previously scheduled deprecations. Most APIs are pretty straightforward
to replace with newer APIs, but perf has a complicated mixed setup with
libbpf used both as static and shared configurations, which makes it
non-trivial to migrate the APIs.

Further, bpf_program__set_prep() needs more involved refactoring, which
will require help from Arnaldo and/or Jiri.

So for now, mute deprecation warnings and work on migrating perf off of
deprecated APIs separately with the input from owners of the perf tool.

Fixes: c93faaaf2f67 ("libbpf: Deprecate bpf_prog_load_xattr() API")
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20211203004640.2455717-1-andrii@kernel.org