[PATCH v6 0/7] perf record: Track sideband events for all CPUs when tracing selected CPUs

From: Yang Jihong
Date: Sun Aug 20 2023 - 21:30:34 EST


User space tasks can migrate between CPUs, track sideband events for all
CPUs.

The specific scenarios are as follows:

CPU0 CPU1
perf record -C 0 start
taskA starts to be created and executed
-> PERF_RECORD_COMM and PERF_RECORD_MMAP
events only deliver to CPU1
......
|
migrate to CPU0
|
Running on CPU0 <----------/
...

perf record -C 0 stop

Now perf samples the PC of taskA. However, perf does not record the
PERF_RECORD_COMM and PERF_RECORD_COMM events of taskA.
Therefore, the comm and symbols of taskA cannot be parsed.

The sys_perf_event_open invoked is as follows:

# perf --debug verbose=3 record -e cpu-clock -C 1 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|CPU|PERIOD|IDENTIFIER
read_format ID|LOST
disabled 1
inherit 1
freq 1
sample_id_all 1
exclude_guest 1
------------------------------------------------------------
sys_perf_event_open: pid -1 cpu 1 group_fd -1 flags 0x8 = 5
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|CPU|IDENTIFIER
read_format ID|LOST
inherit 1
exclude_kernel 1
exclude_hv 1
mmap 1
comm 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 -1 cpu 0 group_fd -1 flags 0x8 = 6
sys_perf_event_open: pid -1 cpu 1 group_fd -1 flags 0x8 = 7
sys_perf_event_open: pid -1 cpu 2 group_fd -1 flags 0x8 = 9
sys_perf_event_open: pid -1 cpu 3 group_fd -1 flags 0x8 = 10
sys_perf_event_open: pid -1 cpu 4 group_fd -1 flags 0x8 = 11
sys_perf_event_open: pid -1 cpu 5 group_fd -1 flags 0x8 = 12
sys_perf_event_open: pid -1 cpu 6 group_fd -1 flags 0x8 = 13
sys_perf_event_open: pid -1 cpu 7 group_fd -1 flags 0x8 = 14
<SNIP>

Changes since_v5:
- No code changes.
- Detailed commit message of patch3.
- Add Acked-by and Tested-by tags from Adrian Hunter.

Changes since_v4:
- Simplify check code for record__tracking_system_wide().
- Add perf attr test result to commit message for patch 7.

Changes since_v3:
- Check fall_kernel, all_user, and dummy or exclude_user when determining
whether system wide is required.

Changes since_v2:
- Rename record_tracking.sh to record_sideband.sh in tools/perf/tests/shell.
- Remove "perf evlist: Skip dummy event sample_type check for evlist_config" patch.
- Add opts->all_kernel check in record__config_tracking_events().
- Add perf_event_attr test for record selected CPUs exclude_user.
- Update base-record & system-wide-dummy sample_type attr expected values for test-record-C0.

Changes since v1:
- Add perf_evlist__go_system_wide() via internal/evlist.h instead of
exporting perf_evlist__propagate_maps().
- Use evlist__add_aux_dummy() instead of evlist__add_dummy() in
evlist__findnew_tracking_event().
- Add a parameter in evlist__findnew_tracking_event() to deal with
system_wide inside.
- Add sideband for all CPUs when tracing selected CPUs comments on
the perf record man page.
- Use "sideband events" instead of "tracking events".
- Adjust the patches Sequence.
- Add patch5 to skip dummy event sample_type check for evlist_config.
- Add patch6 to update system-wide-dummy attr values for perf test.

Yang Jihong (7):
perf evlist: Add perf_evlist__go_system_wide() helper
perf evlist: Add evlist__findnew_tracking_event() helper
perf record: Move setting dummy tracking before
record__init_thread_masks()
perf record: Track sideband events for all CPUs when tracing selected
CPUs
perf test: Update base-record & system-wide-dummy attr expected values
for test-record-C0
perf test: Add test case for record sideband events
perf test: Add perf_event_attr test for record selected CPUs
exclude_user

tools/lib/perf/evlist.c | 9 ++
tools/lib/perf/include/internal/evlist.h | 2 +
tools/perf/Documentation/perf-record.txt | 3 +
tools/perf/builtin-record.c | 106 +++++++++++++-----
tools/perf/tests/attr/system-wide-dummy | 14 ++-
tools/perf/tests/attr/test-record-C0 | 4 +-
.../perf/tests/attr/test-record-C0-all-kernel | 32 ++++++
tools/perf/tests/shell/record_sideband.sh | 44 ++++++++
tools/perf/util/evlist.c | 18 +++
tools/perf/util/evlist.h | 1 +
10 files changed, 198 insertions(+), 35 deletions(-)
create mode 100644 tools/perf/tests/attr/test-record-C0-all-kernel
create mode 100755 tools/perf/tests/shell/record_sideband.sh

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2.30.GIT