perf report: Add 'typeoff' sort key

The typeoff sort key shows the data type name, offset and the name of
the field.  This is useful to see which field in the struct is accessed
most frequently.

  $ perf report -s type,typeoff --hierarchy --stdio
  ...
  #     Overhead  Data Type / Data Type Offset
  # ............  ............................
  #
  ...
        1.23%     struct cfs_rq
           0.19%    struct cfs_rq +404 (throttle_count)
           0.19%    struct cfs_rq +0 (load.weight)
           0.19%    struct cfs_rq +336 (leaf_cfs_rq_list.next)
           0.09%    struct cfs_rq +272 (propagate)
           0.09%    struct cfs_rq +196 (removed.nr)
           0.09%    struct cfs_rq +80 (curr)
           0.09%    struct cfs_rq +544 (lt_b_children_throttled)
           0.06%    struct cfs_rq +320 (rq)

Committer testing:

Again with the perf.data from the previous csets:

  # perf report --stdio -s type,typeoff
  # To display the perf.data header info, please use --header/--header-only options.
  #
  #
  # Total Lost Samples: 0
  #
  # Samples: 4  of event 'cpu_atom/mem-loads,ldlat=30/P'
  # Event count (approx.): 7
  #
  # Overhead  Data Type  Data Type Offset
  # ........  .........  ................
  #
      42.86%  struct list_head  struct list_head +8 (prev)
      42.86%  (unknown)  (unknown) +0 (no field)
      14.29%  char       char +0 (no field)

  #
  # (Tip: To see callchains in a more compact form: perf report -g folded)
  #
  # perf report --stdio -s dso,type,typeoff
  # To display the perf.data header info, please use --header/--header-only options.
  #
  #
  # Total Lost Samples: 0
  #
  # Samples: 4  of event 'cpu_atom/mem-loads,ldlat=30/P'
  # Event count (approx.): 7
  #
  # Overhead  Shared Object         Data Type  Data Type Offset
  # ........  ....................  .........  ................
  #
      42.86%  [kernel.kallsyms]     struct list_head  struct list_head +8 (prev)
      28.57%  libc.so.6             (unknown)  (unknown) +0 (no field)
      14.29%  [kernel.kallsyms]     char       char +0 (no field)
      14.29%  ld-linux-x86-64.so.2  (unknown)  (unknown) +0 (no field)

  #
  # (Tip: If you have debuginfo enabled, try: perf report -s sym,srcline)
  #
  #

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: linux-toolchains@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Link: https://lore.kernel.org/r/20231213001323.718046-13-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt
index aec34417090b..b57eb51b47aa 100644
--- a/tools/perf/Documentation/perf-report.txt
+++ b/tools/perf/Documentation/perf-report.txt
@@ -119,6 +119,7 @@ OPTIONS
 	  to the previous instruction in cycles. And currently supported only on X86
 	- simd: Flags describing a SIMD operation. "e" for empty Arm SVE predicate. "p" for partial Arm SVE predicate
 	- type: Data type of sample memory access.
+	- typeoff: Offset in the data type of sample memory access.
 
 	By default, comm, dso and symbol keys are used.
 	(i.e. --sort comm,dso,symbol)