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_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 | 107 +++++++++++++-----
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, 199 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
--
2.30.GIT
Add a new test case to record sideband events for all CPUs when tracing
selected CPUs
Test result:
# ./perf test list 2>&1 | grep 'perf record sideband tests'
95: perf record sideband tests
# ./perf test 95
95: perf record sideband tests : Ok
Signed-off-by: Yang Jihong <[email protected]>
---
tools/perf/tests/shell/record_sideband.sh | 44 +++++++++++++++++++++++
1 file changed, 44 insertions(+)
create mode 100755 tools/perf/tests/shell/record_sideband.sh
diff --git a/tools/perf/tests/shell/record_sideband.sh b/tools/perf/tests/shell/record_sideband.sh
new file mode 100755
index 000000000000..2ecf00011cb1
--- /dev/null
+++ b/tools/perf/tests/shell/record_sideband.sh
@@ -0,0 +1,44 @@
+#!/bin/sh
+# perf record sideband tests
+# SPDX-License-Identifier: GPL-2.0
+
+set -e
+
+err=0
+perfdata=$(mktemp /tmp/__perf_test.perf.data.XXXXX)
+
+can_cpu_wide()
+{
+ if ! perf record -o ${perfdata} -BN --no-bpf-event -C $1 true 2>&1 >/dev/null
+ then
+ echo "record sideband test [Skipped cannot record cpu$1]"
+ err=2
+ fi
+
+ rm -f ${perfdata}
+ return $err
+}
+
+test_system_wide_tracking()
+{
+ # Need CPU 0 and CPU 1
+ can_cpu_wide 0 || return 0
+ can_cpu_wide 1 || return 0
+
+ # Record on CPU 0 a task running on CPU 1
+ perf record -BN --no-bpf-event -o ${perfdata} -C 0 -- taskset --cpu-list 1 true
+
+ # Should get MMAP events from CPU 1
+ mmap_cnt=`perf script -i ${perfdata} --show-mmap-events -C 1 2>/dev/null | grep MMAP | wc -l`
+
+ rm -f ${perfdata}
+
+ if [ ${mmap_cnt} -gt 0 ] ; then
+ return 0
+ fi
+
+ echo "Failed to record MMAP events on CPU 1 when tracing CPU 0"
+ return 1
+}
+
+test_system_wide_tracking
--
2.30.GIT
Currently, intel-bts, intel-pt, and arm-spe may add a dummy event for
tracking to the evlist. We may need to search for the dummy event for
some settings. Therefore, add evlist__findnew_tracking_event() helper.
evlist__findnew_tracking_event() also deal with system_wide maps if
system_wide is true.
Signed-off-by: Yang Jihong <[email protected]>
---
tools/perf/builtin-record.c | 11 +++--------
tools/perf/util/evlist.c | 18 ++++++++++++++++++
tools/perf/util/evlist.h | 1 +
3 files changed, 22 insertions(+), 8 deletions(-)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index aec18db7ff23..ca83599cc50c 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1295,14 +1295,9 @@ static int record__open(struct record *rec)
*/
if (opts->target.initial_delay || target__has_cpu(&opts->target) ||
perf_pmus__num_core_pmus() > 1) {
- pos = evlist__get_tracking_event(evlist);
- if (!evsel__is_dummy_event(pos)) {
- /* Set up dummy event. */
- if (evlist__add_dummy(evlist))
- return -ENOMEM;
- pos = evlist__last(evlist);
- evlist__set_tracking_event(evlist, pos);
- }
+ pos = evlist__findnew_tracking_event(evlist, false);
+ if (!pos)
+ return -ENOMEM;
/*
* Enable the dummy event when the process is forked for
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 7ef43f72098e..25c3ebe2c2f5 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1694,6 +1694,24 @@ void evlist__set_tracking_event(struct evlist *evlist, struct evsel *tracking_ev
tracking_evsel->tracking = true;
}
+struct evsel *evlist__findnew_tracking_event(struct evlist *evlist, bool system_wide)
+{
+ struct evsel *evsel;
+
+ evsel = evlist__get_tracking_event(evlist);
+ if (!evsel__is_dummy_event(evsel)) {
+ evsel = evlist__add_aux_dummy(evlist, system_wide);
+ if (!evsel)
+ return NULL;
+
+ evlist__set_tracking_event(evlist, evsel);
+ } else if (system_wide) {
+ perf_evlist__go_system_wide(&evlist->core, &evsel->core);
+ }
+
+ return evsel;
+}
+
struct evsel *evlist__find_evsel_by_str(struct evlist *evlist, const char *str)
{
struct evsel *evsel;
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index 664c6bf7b3e0..98e7ddb2bd30 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -387,6 +387,7 @@ bool evlist_cpu_iterator__end(const struct evlist_cpu_iterator *evlist_cpu_itr);
struct evsel *evlist__get_tracking_event(struct evlist *evlist);
void evlist__set_tracking_event(struct evlist *evlist, struct evsel *tracking_evsel);
+struct evsel *evlist__findnew_tracking_event(struct evlist *evlist, bool system_wide);
struct evsel *evlist__find_evsel_by_str(struct evlist *evlist, const char *str);
--
2.30.GIT
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 <[email protected]>
---
tools/perf/tests/attr/system-wide-dummy | 14 ++++++++------
tools/perf/tests/attr/test-record-C0 | 4 ++--
2 files changed, 10 insertions(+), 8 deletions(-)
diff --git a/tools/perf/tests/attr/system-wide-dummy b/tools/perf/tests/attr/system-wide-dummy
index 2f3e3eb728eb..a1e1d6a263bf 100644
--- a/tools/perf/tests/attr/system-wide-dummy
+++ b/tools/perf/tests/attr/system-wide-dummy
@@ -9,8 +9,10 @@ flags=8
type=1
size=136
config=9
-sample_period=4000
-sample_type=455
+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
@@ -18,12 +20,12 @@ inherit=1
pinned=0
exclusive=0
exclude_user=0
-exclude_kernel=0
-exclude_hv=0
+exclude_kernel=1
+exclude_hv=1
exclude_idle=0
mmap=1
comm=1
-freq=1
+freq=0
inherit_stat=0
enable_on_exec=0
task=1
@@ -32,7 +34,7 @@ precise_ip=0
mmap_data=0
sample_id_all=1
exclude_host=0
-exclude_guest=0
+exclude_guest=1
exclude_callchain_kernel=0
exclude_callchain_user=0
mmap2=1
diff --git a/tools/perf/tests/attr/test-record-C0 b/tools/perf/tests/attr/test-record-C0
index 317730b906dd..198e8429a1bf 100644
--- a/tools/perf/tests/attr/test-record-C0
+++ b/tools/perf/tests/attr/test-record-C0
@@ -10,9 +10,9 @@ cpu=0
enable_on_exec=0
# PERF_SAMPLE_IP | PERF_SAMPLE_TID | PERF_SAMPLE_TIME |
-# PERF_SAMPLE_ID | PERF_SAMPLE_PERIOD
+# PERF_SAMPLE_PERIOD | PERF_SAMPLE_IDENTIFIER
# + PERF_SAMPLE_CPU added by -C 0
-sample_type=455
+sample_type=65927
# Dummy event handles mmaps, comm and task.
mmap=0
--
2.30.GIT