linux-stable.git/tools/perf/util/config.c, branch linux-rolling-stable

perf unwind: Refactor get_entries to allow dynamic libdw/libunwind selection

2026-07-24T14:20:00+00:00

[ Upstream commit 4248ae6e799605b3e62855be6085935d89de50d1 ]

Currently, both libdw and libunwind define 'unwind__get_entries'. This
causes a duplicate symbol build failure when both are compiled into
perf.

This commit refactors the DWARF unwind post-processing to be
configurable at runtime via the .perfconfig file option
'unwind.style', or using the argument '--unwind-style' in the commands
'perf report', 'perf script' and 'perf inject', in a similar manner to
the addr2line or the disassembler style.

The file 'tools/perf/util/unwind.c' adds the top-level dispatch
function 'unwind__get_entries'. The backend implementations are
renamed to 'libdw__get_entries' and 'libunwind__get_entries'. Both are
attempted as fallbacks if not configured, or if the primary backend
fails.

Fixes: 2e9191573a69ff96 ("perf build: Remove NO_LIBDW_DWARF_UNWIND option")
Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Albert Ou 
Cc: Alexander Shishkin 
Cc: Alexandre Ghiti 
Cc: Andrew Jones 
Cc: Athira Rajeev 
Cc: Dapeng Mi 
Cc: Dmitrii Dolgov <9erthalion6@gmail.com>
Cc: Florian Fainelli 
Cc: Howard Chu 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: John Garry 
Cc: Leo Yan 
Cc: libunwind-devel@nongnu.org
Cc: Li Guan 
Cc: Namhyung Kim 
Cc: Palmer Dabbelt 
Cc: Paul Walmsley 
Cc: Peter Zijlstra 
Cc: Shimin Guo 
Cc: Thomas Richter 
Cc: Tomas Glozar 
Cc: Will Deacon 
[ Don't mix declarations and code, move 'entries' variable to the start of scope ]
[ Use pr_warning_once() instead of pr_err() in stubs for get_entries(), suggested by a local sashiko instance ]
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Sasha Levin

perf addr2line: Remove global variable addr2line_timeout_ms

2026-04-08T17:28:49+00:00

Remove global variable addr2line_timeout_ms and add it as a member
to symbol_conf structure.

Signed-off-by: Thomas Richter 
Reviewed-by: Ian Rogers 
[namhyung: move the initialization to util/symbol.c]
Signed-off-by: Namhyung Kim

perf config: Make symbol_conf::addr2line_disable_warn configurable

2026-04-08T17:28:49+00:00

Make symbol_conf::addr2line_disable_warn configurable by reading
the perfconfig file.
Use section core and addr2line-disable-warn = value.
Update documentation.

Example:
 # perf config -l
 core.addr2line-timeout=5000
 core.addr2line-disable-warn=1
 #

Signed-off-by: Thomas Richter 
Reviewed-by: Ian Rogers 
Suggested-by: Namhyung Kim 
Signed-off-by: Namhyung Kim

perf srcline: Add configuration support for the addr2line style

2026-01-13T19:09:14+00:00

Allow the addr2line style to be specified on the `perf report` command
line or in the .perfconfig file.

Committer testing:

The methods:

  # perf probe -x ~/bin/perf -F *__addr2line
  cmd__addr2line
  libbfd__addr2line
  libdw__addr2line
  llvm__addr2line
  #

So if we configure one of them, say 'addr2line':

  # perf config addr2line.style=addr2line
  # perf config addr2line.style
  addr2line.style=addr2line
  #

And have probes on all of them:

  # perf probe -x ~/bin/perf *__addr2line
  Added new events:
    probe_perf:cmd__addr2line (on *__addr2line in /home/acme/bin/perf)
    probe_perf:llvm__addr2line (on *__addr2line in /home/acme/bin/perf)
    probe_perf:libbfd__addr2line (on *__addr2line in /home/acme/bin/perf)
    probe_perf:libdw__addr2line (on *__addr2line in /home/acme/bin/perf)

  You can now use it in all perf tools, such as:

  	perf record -e probe_perf:libdw__addr2line -aR sleep 1

  #

Only the selected method should be used:

  # perf stat -e probe_perf:*_addr2line perf report -f --dso perf --stdio -s srcfile,srcline
  # Total Lost Samples: 0
  #
  # Samples: 4K of event 'cpu/cycles/Pu'
  # Event count (approx.): 5535180842
  #
  # Overhead  Source File   Source:Line
  # ........  ............  ...............
  #
      99.04%  inlineloop.c  inlineloop.c:21
       0.46%  inlineloop.c  inlineloop.c:20

  #
  # (Tip: For hierarchical output, try: perf report --hierarchy)
  #

   Performance counter stats for 'perf report -f --dso perf --stdio -s srcfile,srcline':

                  44      probe_perf:cmd__addr2line
                   0      probe_perf:llvm__addr2line
                   0      probe_perf:libbfd__addr2line
                   0      probe_perf:libdw__addr2line

         0.035915611 seconds time elapsed

         0.028008000 seconds user
         0.009051000 seconds sys
  #

I checked and that is the case for the other methods.

Also when using:

  # perf config addr2line.style=libdw,llvm

 Performance counter stats for 'perf report -f --dso perf --stdio -s srcfile,srcline':

                 0      probe_perf:cmd__addr2line
                23      probe_perf:llvm__addr2line
                 0      probe_perf:libbfd__addr2line
                44      probe_perf:libdw__addr2line

Reviewed-by: James Clark 
Signed-off-by: Ian Rogers 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Howard Chu 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Stephen Brennan 
Cc: Tony Jones 
Signed-off-by: Arnaldo Carvalho de Melo

perf stat: Reduce scope of walltime_nsecs_stats

2025-11-18T02:43:09+00:00

walltime_nsecs_stats is no longer used for counter values, move into
that stat_config where it controls certain things like noise
measurement.

Signed-off-by: Ian Rogers 
Signed-off-by: Namhyung Kim

perf stat: Reduce scope of ru_stats

2025-11-18T02:43:09+00:00

The ru_stats are used to capture user and system time stats when a
process exits. These are then applied to user and system time tool
events if their reads fail due to the process terminating. Reduce the
scope now the metric code no longer reads these values.

Signed-off-by: Ian Rogers 
Signed-off-by: Namhyung Kim

perf srcline: Fallback between addr2line implementations

2025-10-06T19:47:49+00:00

Factor the addr2line function implementation into separate source files
(addr2line.[ch]) and rename the addr2line function cmd__addr2line. In
srcline replace the ifdef-ed addr2line implementations with one that
first tries the llvm__addr2line implementation, then the deprecated
libbfd__addr2line function and on failure uses cmd__addr2line.

If HAVE_LIBLLVM_SUPPORT is enabled the llvm__addr2line will execute
against the libLLVM.so it is linked against.

If HAVE_LIBLLVM_DYNAMIC is enabled then libperf-llvm.so (that links
against libLLVM.so) will be dlopened. If the dlopen succeeds then the
behavior should match HAVE_LIBLLVM_SUPPORT. On failure cmd__addr2line is
used. The dlopen is only tried once.

If HAVE_LIBLLVM_DYNAMIC isn't enabled then llvm__addr2line immediately
fails and cmd__addr2line is used.

Clean up the dso__free_a2l logic, which is only needed in the non-LLVM
version and moved to addr2line.c.

Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Alexandre Ghiti 
Cc: Andi Kleen 
Cc: Athira Rajeev 
Cc: Bill Wendling 
Cc: Charlie Jenkins 
Cc: Collin Funk 
Cc: Dmitriy Vyukov 
Cc: Dr. David Alan Gilbert 
Cc: Eric Biggers 
Cc: Haibo Xu 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: Justin Stitt 
Cc: Li Huafei 
Cc: Masami Hiramatsu 
Cc: Namhyung Kim 
Cc: Nathan Chancellor 
Cc: Nick Desaulniers 
Cc: Peter Zijlstra 
Cc: Song Liu 
Cc: Stephen Brennan 
Signed-off-by: Arnaldo Carvalho de Melo

perf util: Remove unused perf_config__refresh

2025-03-10T18:31:24+00:00

perf_config__refresh() was added in 2016 by
commit 8a0a9c7e9146 ("perf config: Introduce new init() and exit()")
but has remained unused.

Remove it.

Signed-off-by: Dr. David Alan Gilbert 
Reviewed-by: Ian Rogers 
Link: https://lore.kernel.org/r/20250305023120.155420-7-linux@treblig.org
Signed-off-by: Namhyung Kim

perf stat: Move stat_config into config.c

2024-12-18T19:24:32+00:00

stat_config is accessed by config.c via helper functions, but declared
in builtin-stat. Move to util/config.c so that stub functions aren't
needed in python.c which doesn't link against the builtin files.

To avoid name conflicts change builtin-script to use the same
stat_config as builtin-stat. Rename local variables in tests to avoid
shadow declaration warnings.

Signed-off-by: Ian Rogers 
Tested-by: Arnaldo Carvalho de Melo 
Acked-by: Arnaldo Carvalho de Melo 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Athira Rajeev 
Cc: Colin Ian King 
Cc: Dapeng Mi 
Cc: Howard Chu 
Cc: Ilya Leoshkevich 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: Josh Poimboeuf 
Cc: Kan Liang 
Cc: Mark Rutland 
Cc: Michael Petlan 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Thomas Richter 
Cc: Veronika Molnarova 
Cc: Weilin Wang 
Link: https://lore.kernel.org/r/20241119011644.971342-9-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

perf scripting python: Add function to get a config value

2024-09-24T18:47:03+00:00

This can be used to get config values like which objdump Perf uses for
disassembly.

Reviewed-by: Leo Yan 
Signed-off-by: James Clark 
Tested-by: Ganapatrao Kulkarni 
Cc: Ben Gainey 
Cc: Suzuki K Poulose 
Cc: Will Deacon 
Cc: Mathieu Poirier 
Cc: Mike Leach 
Cc: Ruidong Tian 
Cc: Leo Yan 
Cc: Benjamin Gray 
Cc: linux-arm-kernel@lists.infradead.org
Cc: coresight@lists.linaro.org
Cc: John Garry 
Cc: scclevenger@os.amperecomputing.com
Link: https://lore.kernel.org/r/20240916135743.1490403-4-james.clark@linaro.org
Signed-off-by: Namhyung Kim