linux.git/tools/perf/builtin-diff.c, branch v7.1-rc2

perf tools: Use calloc() where applicable

2026-04-09T02:21:05+00:00

Instead of using zalloc(nr_entries * sizeof_entry) that is what calloc()
does.

In some places where linux/zalloc.h isn't needed, remove it, add when
needed and was getting it indirectly.

Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Namhyung Kim

perf tools: Make more global variables static

2026-04-09T02:21:04+00:00

`make check` will run sparse on the perf code base. A frequent warning
is "warning: symbol '...' was not declared. Should it be static?" Go
through and make global definitions without declarations static.

In some cases it is deliberate due to dlsym accessing the symbol, this
change doesn't clean up the missing declarations for perf test suites.

Sometimes things can opportunistically be made const.

Making somethings static exposed unused functions warnings, so
restructuring of ifdefs was necessary for that.

These changes reduce the size of the perf binary by 568 bytes.

Committer notes:

Refreshed the patch, the original one fell thru the cracks, updated the
size reduction.

Remove the trace-event-scripting.c changes, break the build, noticed
with container builds and with sashiko:

  https://sashiko.dev/#/patchset/20260401215306.2152898-1-acme%40kernel.org

Also make two variables static to address another sashiko review
comment:

  https://sashiko.dev/#/patchset/20260402001740.2220481-1-acme%40kernel.org

Signed-off-by: Ian Rogers 
Acked-by: Ankur Arora 
Acked-by: Namhyung Kim 
Cc: Adrian Hunter 
Cc: Albert Ou 
Cc: Alexander Shishkin 
Cc: Alexandre Ghiti 
Cc: Athira Rajeev 
Cc: Guo Ren 
Cc: Howard Chu 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: Leo Yan 
Cc: Masami Hiramatsu 
Cc: Palmer Dabbelt 
Cc: Paul Walmsley 
Cc: Peter Zijlstra 
Cc: Yujie Liu 
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Namhyung Kim

perf config: Rename symbol_conf::disable_add2line_warn

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

Rename member symbol_conf::disable_add2line_warn to
symbol_conf::addr2line_disable_warn to make it consistent with other
addr2line_xxx constants.

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

perf tools: Add layout support for --symfs option

2026-03-11T06:13:30+00:00

Add support for parsing an optional layout parameter in the --symfs
command line option. The format is:

  --symfs 

Where layout can be:
  - 'hierarchy': matches full path (default)
  - 'flat': only matches base name

When debugging symbol files from a copy of the filesystem (e.g., from a
container or remote machine), the debug files are often stored in a
flat directory structure with only filenames, not the full original
paths. In this case, using 'flat' layout allows perf to find debug
symbols by matching only the filename rather than the full path.

For example, given a binary path like:
  /build/output/lib/foo.so

With 'perf report --symfs /debug/files,flat', perf will look for:
  /debug/files/foo.so

Instead of:
  /debug/files/build/output/lib/foo.so

This is particularly useful when:
- Extracting debug files from containers with different directory layouts
- Working with build systems that flatten directory structures

Signed-off-by: Changbin Du 
Signed-off-by: Namhyung Kim

perf diff: Constify strchr() return variables

2025-12-17T12:30:37+00:00

Newer glibc versions return const char for strchr() when the 's' arg is
const, change the return variable to const to match that.

Also we don't need to turn that ',' into a '\0', as strtol() will stop
in the first invalid char. No need to touch read only memory.

First noticed with fedora 44.

Reviewed-by: Ian Rogers 
Link: https://lore.kernel.org/r/20251211221756.96294-3-acme@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf sort: Use perf_env to set arch sort keys and header

2025-07-25T17:37:58+00:00

Previously arch_support_sort_key and arch_perf_header_entry used a
weak symbol to compile as appropriate for x86 and powerpc. A
limitation to this is that the handling of a data file could vary in
cross-platform development. Change to using the perf_env of the
current session to determine the architecture kind and set the sort
key and header entries as appropriate.

Signed-off-by: Ian Rogers 
Link: https://lore.kernel.org/r/20250724163302.596743-23-irogers@google.com
Signed-off-by: Namhyung Kim

perf stream: Use evsel rather than evsel->idx

2024-12-23T16:53:08+00:00

An evsel idx may not be stable due to sorting, evlist removal,
etc. Avoid use of the idx where the evsel itself can be used to avoid
these problems.

Reviewed-by: James Clark 
Reviewed-by: Namhyung Kim 
Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Ahelenia Ziemiańska 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Chen Ni 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Mark Rutland 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20241114230713.330701-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

perf cpumap: Reduce transitive dependencies on libperf MAX_NR_CPUS

2024-12-09T20:52:41+00:00

libperf exposes MAX_NR_CPUS via tools/lib/perf/include/internal/cpumap.h
which is internal.

The preferred dependency should be the definition in tools/perf/perf.h.

Add the includes of perf.h so that MAX_NR_CPUS can be hidden in libperf.

Reviewed-by: Leo Yan 
Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Ben Gainey 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Kyle Meyer 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20241206044035.1062032-3-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

perf evsel: Add alternate_hw_config and use in evsel__match

2024-09-26T20:26:11+00:00

There are cases where we want to match events like instructions and
cycles with legacy hardware values, in particular in stat-shadow's
hard coded metrics. An evsel's name isn't a good point of reference as
it gets altered, strstr would be too imprecise and re-parsing the
event from its name is silly. Instead, hold the legacy hardware event
name, determined during parsing, in the evsel for this matching case.

Inline evsel__match2 that is only used in builtin-diff.

Acked-by: Namhyung Kim 
Signed-off-by: Ian Rogers 
Acked-by: Kan Liang 
Signed-off-by: James Clark 
Cc: Yang Jihong 
Cc: Dominique Martinet 
Cc: Colin Ian King 
Cc: Howard Chu 
Cc: Yunseong Kim 
Cc: Ze Gao 
Cc: Yicong Yang 
Cc: Weilin Wang 
Cc: Will Deacon 
Cc: Mike Leach 
Cc: Jing Zhang 
Cc: Yang Li 
Cc: Leo Yan 
Cc: ak@linux.intel.com
Cc: Athira Rajeev 
Cc: linux-arm-kernel@lists.infradead.org
Cc: Sun Haiyong 
Cc: John Garry 
Link: https://lore.kernel.org/r/20240926144851.245903-2-james.clark@linaro.org
Signed-off-by: Namhyung Kim

perf report: Display the branch counter histogram

2024-08-14T13:20:40+00:00

Reusing the existing --total-cycles option to display the branch
counters. Add a new PERF_HPP_REPORT__BLOCK_BRANCH_COUNTER to display
the logged branch counter events. They are shown right after all the
cycle-related annotations.

Extend the 'struct block_info' to store and pass the branch counter
related information.

The annotation_br_cntr_entry() is to print the histogram of each branch
counter event. If the number of logged events is less than 4, the exact
number of the abbr name is printed. Otherwise, using '+' to stands for
more than 3 events.

Assume the number of logged events is less than 4.

The annotation_br_cntr_abbr_list() prints the branch counter's
abbreviation list. Press 'B' to display the list in the TUI mode.

  $ perf record -e "{branch-instructions:ppp,branch-misses}:S" -j any,counter
  $ perf report  --total-cycles --stdio

  # To display the perf.data header info, please use --header/--header-only options.
  #
  #
  # Total Lost Samples: 0
  #
  # Samples: 1M of events 'anon group { branch-instructions:ppp, branch-misses }'
  # Event count (approx.): 1610046
  #
  # Branch counter abbr list:
  # branch-instructions:ppp = A
  # branch-misses = B
  # '-' No event occurs
  # '+' Event occurrences may be lost due to branch counter saturated
  #
  # Sampled Cycles%  Sampled Cycles  Avg Cycles%  Avg Cycles  Branch Counter [Program Block Range]
  # ...............  ..............  ...........  ..........  ..............  ..................
  #
            57.55%            2.5M        0.00%           3     |A   |-   |                 ...
            25.27%            1.1M        0.00%           2     |AA  |-   |                 ...
            15.61%          667.2K        0.00%           1     |A   |-   |                 ...
             0.16%            6.9K        0.81%         575     |A   |-   |                 ...
             0.16%            6.8K        1.38%         977     |AA  |-   |                 ...
             0.16%            6.8K        0.04%          28     |AA  |B   |                 ...
             0.15%            6.6K        1.33%         946     |A   |-   |                 ...
             0.11%            4.5K        0.06%          46     |AAA+|-   |                 ...
             0.10%            4.4K        0.88%         624     |A   |-   |                 ...
             0.09%            3.7K        0.74%         524     |AAA+|B   |                 ...

With -v applied,

  # Sampled Cycles%  Sampled Cycles  Avg Cycles%  Avg Cycles  Branch Counter [Program Block Range]
  # ...............  ..............  ...........  ..........  ..............  ..................
  #
            57.55%            2.5M        0.00%           3       A=1 ,B=-                  ...
            25.27%            1.1M        0.00%           2       A=2 ,B=-                  ...
            15.61%          667.2K        0.00%           1       A=1 ,B=-                  ...
             0.16%            6.9K        0.81%         575       A=1 ,B=-                  ...
             0.16%            6.8K        1.38%         977       A=2 ,B=-                  ...
             0.16%            6.8K        0.04%          28       A=2 ,B=1                  ...
             0.15%            6.6K        1.33%         946       A=1 ,B=-                  ...
             0.11%            4.5K        0.06%          46       A=3+,B=-                  ...
             0.10%            4.4K        0.88%         624       A=1 ,B=-                  ...
             0.09%            3.7K        0.74%         524       A=3+,B=1                  ...

Reviewed-by: Andi Kleen 
Signed-off-by: Kan Liang 
Acked-by: Namhyung Kim 
Cc: Adrian Hunter 
Cc: Ian Rogers 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: https://lore.kernel.org/r/20240813160208.2493643-7-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo