linux/tools/perf/tests/attr/system-wide-dummy
Yang Jihong 1285ab300d perf record: Move setting tracking events before record__init_thread_masks()
User space tasks can migrate between CPUs, so when tracing selected CPUs,
sideband for all CPUs is needed. In this case set the cpu map of the evsel
to all online CPUs. This may modify the original cpu map of the evlist.

Therefore, need to check whether the preceding scenario exists before
record__init_thread_masks().

Dummy tracking has been set in record__open(), move it before
record__init_thread_masks() and add a helper for unified processing.

The sys_perf_event_open invoked is as follows:

  # perf --debug verbose=3 record -e cpu-clock -D 100 true
  <SNIP>
  Opening: cpu-clock
  ------------------------------------------------------------
  perf_event_attr:
    type                             1 (PERF_TYPE_SOFTWARE)
    size                             136
    config                           0 (PERF_COUNT_SW_CPU_CLOCK)
    { sample_period, sample_freq }   4000
    sample_type                      IP|TID|TIME|PERIOD|IDENTIFIER
    read_format                      ID|LOST
    disabled                         1
    inherit                          1
    freq                             1
    sample_id_all                    1
    exclude_guest                    1
  ------------------------------------------------------------
  sys_perf_event_open: pid 10318  cpu 0  group_fd -1  flags 0x8 = 5
  sys_perf_event_open: pid 10318  cpu 1  group_fd -1  flags 0x8 = 6
  sys_perf_event_open: pid 10318  cpu 2  group_fd -1  flags 0x8 = 7
  sys_perf_event_open: pid 10318  cpu 3  group_fd -1  flags 0x8 = 9
  sys_perf_event_open: pid 10318  cpu 4  group_fd -1  flags 0x8 = 10
  sys_perf_event_open: pid 10318  cpu 5  group_fd -1  flags 0x8 = 11
  sys_perf_event_open: pid 10318  cpu 6  group_fd -1  flags 0x8 = 12
  sys_perf_event_open: pid 10318  cpu 7  group_fd -1  flags 0x8 = 13
  Opening: dummy:u
  ------------------------------------------------------------
  perf_event_attr:
    type                             1 (PERF_TYPE_SOFTWARE)
    size                             136
    config                           0x9 (PERF_COUNT_SW_DUMMY)
    { sample_period, sample_freq }   1
    sample_type                      IP|TID|TIME|IDENTIFIER
    read_format                      ID|LOST
    disabled                         1
    inherit                          1
    exclude_kernel                   1
    exclude_hv                       1
    mmap                             1
    comm                             1
    enable_on_exec                   1
    task                             1
    sample_id_all                    1
    exclude_guest                    1
    mmap2                            1
    comm_exec                        1
    ksymbol                          1
    bpf_event                        1
  ------------------------------------------------------------
  sys_perf_event_open: pid 10318  cpu 0  group_fd -1  flags 0x8 = 14
  sys_perf_event_open: pid 10318  cpu 1  group_fd -1  flags 0x8 = 15
  sys_perf_event_open: pid 10318  cpu 2  group_fd -1  flags 0x8 = 16
  sys_perf_event_open: pid 10318  cpu 3  group_fd -1  flags 0x8 = 17
  sys_perf_event_open: pid 10318  cpu 4  group_fd -1  flags 0x8 = 18
  sys_perf_event_open: pid 10318  cpu 5  group_fd -1  flags 0x8 = 19
  sys_perf_event_open: pid 10318  cpu 6  group_fd -1  flags 0x8 = 20
  sys_perf_event_open: pid 10318  cpu 7  group_fd -1  flags 0x8 = 21
  <SNIP>

'perf test' needs to update base-record & system-wide-dummy attr expected values
for test-record-C0:

1. Because a dummy sideband event is added to the sampling of specified
   CPUs. When evlist contains evsel of different sample_type,
   evlist__config() will change the default PERF_SAMPLE_ID bit to
   PERF_SAMPLE_IDENTIFICATION bit.
   The attr sample_type expected value of base-record and system-wide-dummy
   in test-record-C0 needs to be updated.

2. The perf record uses evlist__add_aux_dummy() instead of
   evlist__add_dummy() to add a dummy event.
   The expected value of system-wide-dummy attr needs to be updated.

The 'perf test' result is as follows:

  # ./perf test list  2>&1 | grep 'Setup struct perf_event_attr'
   17: Setup struct perf_event_attr
  # ./perf test 17
   17: Setup struct perf_event_attr                                    : Ok

Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Link: https://lore.kernel.org/r/20230904023340.12707-4-yangjihong1@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2023-09-12 17:31:37 -03:00

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# Event added by system-wide or CPU perf-record to handle the race of
# processes starting while /proc is processed.
[event]
fd=1
group_fd=-1
cpu=*
pid=-1
flags=8
type=1
size=136
config=9
sample_period=1
# PERF_SAMPLE_IP | PERF_SAMPLE_TID | PERF_SAMPLE_TIME |
# PERF_SAMPLE_CPU | PERF_SAMPLE_IDENTIFIER
sample_type=65671
read_format=4|20
# Event will be enabled right away.
disabled=0
inherit=1
pinned=0
exclusive=0
exclude_user=0
exclude_kernel=1
exclude_hv=1
exclude_idle=0
mmap=1
comm=1
freq=0
inherit_stat=0
enable_on_exec=0
task=1
watermark=0
precise_ip=0
mmap_data=0
sample_id_all=1
exclude_host=0
exclude_guest=1
exclude_callchain_kernel=0
exclude_callchain_user=0
mmap2=1
comm_exec=1
context_switch=0
write_backward=0
namespaces=0
use_clockid=0
wakeup_events=0
bp_type=0
config1=0
config2=0
branch_sample_type=0
sample_regs_user=0
sample_stack_user=0