linux.git/tools/perf/util, branch v6.8-rc2

perf db-export: Fix missing reference count get in call_path_from_sample()

2024-01-04T21:29:17+00:00

The addr_location map and maps fields in the inner loop were missing
calls to map__get()/maps__get(). The subsequent addr_location__exit()
call in each loop puts the map/maps fields causing use-after-free
aborts.

This issue reproduces on at least arm64 and x86_64 with something
simple like `perf record -g ls` followed by `perf script -s script.py`
with the following script:

    perf_db_export_mode = True
    perf_db_export_calls = False
    perf_db_export_callchains = True

    def sample_table(*args):
        print(f'sample_table({args})')

    def call_path_table(*args):
        print(f'call_path_table({args}')

Committer testing:

This test, just introduced by Ian Rogers, now passes, not segfaulting
anymore:

  # perf test "perf script tests"
   95: perf script tests                                               : Ok
  #

Fixes: 0dd5041c9a0eaf8c ("perf addr_location: Add init/exit/copy functions")
Signed-off-by: Ben Gainey 
Tested-by: Arnaldo Carvalho de Melo 
Tested-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20231207140911.3240408-1-ben.gainey@arm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf stat: Fix hard coded LL miss units

2024-01-03T20:55:01+00:00

Copy-paste error where LL cache misses are reported as l1i.

Fixes: 0a57b910807ad163 ("perf stat: Use counts rather than saved_value")
Suggested-by: Guillaume Endignoux 
Reviewed-by: Kan Liang 
Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Ian Rogers 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: John Garry 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20231211181242.1721059-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

perf env: Avoid recursively taking env->bpf_progs.lock

2024-01-03T20:54:54+00:00

Add variants of perf_env__insert_bpf_prog_info(), perf_env__insert_btf()
and perf_env__find_btf prefixed with __ to indicate the
env->bpf_progs.lock is assumed held.

Call these variants when the lock is held to avoid recursively taking it
and potentially having a thread deadlock with itself.

Fixes: f8dfeae009effc0b ("perf bpf: Show more BPF program info in print_bpf_prog_info()")
Signed-off-by: Ian Rogers 
Acked-by: Jiri Olsa 
Acked-by: Song Liu 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Huacai Chen 
Cc: Ingo Molnar 
Cc: K Prateek Nayak 
Cc: Kan Liang 
Cc: Mark Rutland 
Cc: Ming Wang 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Ravi Bangoria 
Link: https://lore.kernel.org/r/20231207014655.1252484-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Add --insn-stat option for debugging

2023-12-24T01:40:17+00:00

This is for a debugging purpose.  It'd be useful to see per-instrucion
level success/failure stats.

  $ perf annotate --data-type --insn-stat
  Annotate Instruction stats
  total 264, ok 143 (54.2%), bad 121 (45.8%)

    Name      :  Good   Bad
  -----------------------------------------------------------
    movq      :    45    31
    movl      :    22    11
    popq      :     0    19
    cmpl      :    16     3
    addq      :     8     7
    cmpq      :    11     3
    cmpxchgl  :     3     7
    cmpxchgq  :     8     0
    incl      :     3     3
    movzbl    :     4     2
    incq      :     4     2
    decl      :     6     0
    ...

Committer notes:

So these are about being able to find the type for accesses from these
instructions, we should improve the naming, but it is for debugging, we
can improve this later:

  @@ -3726,6 +3759,10 @@ struct annotated_data_type *hist_entry__get_data_type(struct hist_entry *he)
                          continue;

                  mem_type = find_data_type(ms, ip, op_loc->reg, op_loc->offset);
  +               if (mem_type)
  +                       istat->good++;
  +               else
  +                       istat->bad++;

Signed-off-by: Namhyung Kim 
Cc: Adrian Hunter 
Cc: Ian Rogers 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Masami Hiramatsu 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: linux-toolchains@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Link: https://lore.kernel.org/r/20231213001323.718046-18-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Add --type-stat option for debugging

2023-12-24T01:40:13+00:00

The --type-stat option is to be used with --data-type and to print
detailed failure reasons for the data type annotation.

  $ perf annotate --data-type --type-stat
  Annotate data type stats:
  total 294, ok 116 (39.5%), bad 178 (60.5%)
  -----------------------------------------------------------
          30 : no_sym
          40 : no_insn_ops
          33 : no_mem_ops
          63 : no_var
           4 : no_typeinfo
           8 : bad_offset

Signed-off-by: Namhyung Kim 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Adrian Hunter 
Cc: Ian Rogers 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Masami Hiramatsu 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: linux-toolchains@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Link: https://lore.kernel.org/r/20231213001323.718046-17-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Add --data-type option

2023-12-24T01:39:43+00:00

Support data type annotation with new --data-type option.  It internally
uses type sort key to collect sample histogram for the type and display
every members like below.

  $ perf annotate --data-type
  ...
  Annotate type: 'struct cfs_rq' in [kernel.kallsyms] (13 samples):
  ============================================================================
      samples     offset       size  field
           13          0        640  struct cfs_rq         {
            2          0         16      struct load_weight       load {
            2          0          8          unsigned long        weight;
            0          8          4          u32  inv_weight;
                                         };
            0         16          8      unsigned long    runnable_weight;
            0         24          4      unsigned int     nr_running;
            1         28          4      unsigned int     h_nr_running;
  ...

For simplicity it prints the number of samples per field for now.
But it should be easy to show the overhead percentage instead.

The number at the outer struct is a sum of the numbers of the inner
members.  For example, struct cfs_rq got total 13 samples, and 2 came
from the load (struct load_weight) and 1 from h_nr_running.  Similarly,
the struct load_weight got total 2 samples and they all came from the
weight field.

I've added two new flags in the symbol_conf for this.  The
annotate_data_member is to get the members of the type.  This is also
needed for perf report with typeoff sort key.  The annotate_data_sample
is to update sample stats for each offset and used only in annotate.

Currently it only support stdio output mode, TUI support can be added
later.

Committer testing:

With the perf.data from the previous csets, a very simple, short
duration one:

  # perf annotate --data-type
  Annotate type: 'struct list_head' in [kernel.kallsyms] (1 samples):
  ============================================================================
      samples     offset       size  field
            1          0         16  struct list_head      {
            0          0          8      struct list_head*        next;
            1          8          8      struct list_head*        prev;
                                     };

  Annotate type: 'char' in [kernel.kallsyms] (1 samples):
  ============================================================================
      samples     offset       size  field
            1          0          1  char ;

  #

Signed-off-by: Namhyung Kim 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Adrian Hunter 
Cc: Ian Rogers 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Masami Hiramatsu 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: linux-toolchains@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Link: https://lore.kernel.org/r/20231213001323.718046-15-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf report: Add 'symoff' sort key

2023-12-24T01:39:42+00:00

The symoff sort key is to print symbol and offset of sample.  This is
useful for data type profiling to show exact instruction in the function
which refers the data.

  $ perf report -s type,sym,typeoff,symoff --hierarchy
  ...
  #       Overhead  Data Type / Symbol / Data Type Offset / Symbol Offset
  # ..............  .....................................................
  #
      1.23%         struct cfs_rq
        0.84%         update_blocked_averages
          0.19%         struct cfs_rq +336 (leaf_cfs_rq_list.next)
             0.19%         [k] update_blocked_averages+0x96
          0.19%         struct cfs_rq +0 (load.weight)
             0.14%         [k] update_blocked_averages+0x104
             0.04%         [k] update_blocked_averages+0x31c
          0.17%         struct cfs_rq +404 (throttle_count)
             0.12%         [k] update_blocked_averages+0x9d
             0.05%         [k] update_blocked_averages+0x1f9
          0.08%         struct cfs_rq +272 (propagate)
             0.07%         [k] update_blocked_averages+0x3d3
             0.02%         [k] update_blocked_averages+0x45b
  ...

Committer testing:

  # perf report --stdio -s type,typeoff,symoff
  # 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  Symbol Offset
  # ........  .........  ................  .............
  #
      42.86%  struct list_head  struct list_head +8 (prev)  [k] __list_del_entry_valid_or_report+0x7
      28.57%  (unknown)  (unknown) +0 (no field)  [.] _nl_intern_locale_data+0x25
      14.29%  char       char +0 (no field)  [k] strncpy_from_user+0xa5
      14.29%  (unknown)  (unknown) +0 (no field)  [.] _dl_lookup_symbol_x+0x50

  #
  # (Tip: To change sampling frequency to 100 Hz: perf record -F 100)
  #

Signed-off-by: Namhyung Kim 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Adrian Hunter 
Cc: Ian Rogers 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Masami Hiramatsu 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: linux-toolchains@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Link: https://lore.kernel.org/r/20231213001323.718046-14-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf report: Add 'typeoff' sort key

2023-12-24T01:39:42+00:00

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 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Adrian Hunter 
Cc: Ian Rogers 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Masami Hiramatsu 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
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

perf annotate-data: Update sample histogram for type

2023-12-24T01:39:42+00:00

The annotated_data_type__update_samples() to get histogram for data type
access.

It'll be called by perf annotate to show which fields in the data type
are accessed frequently.

Signed-off-by: Namhyung Kim 
Cc: Adrian Hunter 
Cc: Ian Rogers 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Masami Hiramatsu 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: linux-toolchains@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Link: https://lore.kernel.org/r/20231213001323.718046-12-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf annotate-data: Add member field in the data type

2023-12-24T01:39:42+00:00

Add child member field if the current type is a composite type like a
struct or union.  The member fields are linked in the children list and
do the same recursively if the child itself is a composite type.

Add 'self' member to the annotated_data_type to handle the members in
the same way.

Signed-off-by: Namhyung Kim 
Cc: Adrian Hunter 
Cc: Ian Rogers 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Masami Hiramatsu 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: linux-toolchains@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Link: https://lore.kernel.org/r/20231213001323.718046-11-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo