[PATCH V2 00/23] perf intel-pt: Better support for perf record --cpu

Adrian Hunter
2022-05-06T12:26:09Z

Hi

Here are V2 patches to support capturing Intel PT sideband events such as
mmap, task, context switch, text poke etc, on every CPU even when tracing
selected user_requested_cpus. That is, when using the perf record -C or
--cpu option.

This is needed for:
1. text poke: a text poke on any CPU affects all CPUs
2. tracing user space: a user space process can migrate between CPUs so
mmap events that happen on a different CPU can be needed to decode a
user_requested_cpus CPU.

For example:

Trace on CPU 1:

perf record --kcore -C 1 -e intel_pt// &

Start a task on CPU 0:

taskset 0x1 testprog &

Migrate it to CPU 1:

taskset -p 0x2 <testprog pid>

Stop tracing:

kill %1

Prior to these changes there will be errors decoding testprog
in userspace because the comm and mmap events for testprog will not
have been captured.

There is quite a bit of preparation:

The first patch is a small Intel PT test for system-wide side band. The
test fails before the patches are applied, passed afterwards.

perf intel-pt: Add a test for system-wide side band [new in V1]

The next 5 patches stop auxtrace mixing up mmap idx between evlist and
evsel. That is going to matter when
evlist->all_cpus != evlist->user_requested_cpus != evsel->cpus:

libperf evsel: Factor out perf_evsel__ioctl() [now applied]
libperf evsel: Add perf_evsel__enable_thread()
perf evlist: Use libperf functions in evlist__enable_event_idx()
perf auxtrace: Move evlist__enable_event_idx() to auxtrace.c
perf auxtrace: Do not mix up mmap idx

The next 6 patches stop attempts to auxtrace mmap when it is not an
auxtrace event e.g. when mmapping the CPUs on which only sideband is
captured:

libperf evlist: Remove ->idx() per_cpu parameter
libperf evlist: Move ->idx() into mmap_per_evsel()
libperf evlist: Add evsel as a parameter to ->idx()
perf auxtrace: Record whether an auxtrace mmap is needed
perf auxctrace: Add mmap_needed to auxtrace_mmap_params
perf auxtrace: Remove auxtrace_mmap_params__set_idx() per_cpu parameter

The next 5 patches switch to setting up dummy event maps before adding the
evsel so that the evsel is subject to map propagation, primarily to cause
addition of the evsel's CPUs to all_cpus.

perf evlist: Factor out evlist__dummy_event()
perf evlist: Add evlist__add_system_wide_dummy()
perf record: Use evlist__add_system_wide_dummy() in record__config_text_poke()
perf intel-pt: Use evlist__add_system_wide_dummy() for switch tracking
perf intel-pt: Track sideband system-wide when needed

The remaining patches make more significant changes.

First change from using user_requested_cpus to using all_cpus where necessary:

perf tools: Allow all_cpus to be a superset of user_requested_cpus

Secondly, mmap all per-thread and all per-cpu events:

libperf evlist: Allow mixing per-thread and per-cpu mmaps
libperf evlist: Check nr_mmaps is correct [new in V1]

Stop using system_wide flag for uncore because it will not work anymore:

perf stat: Add requires_cpu flag for uncore
libperf evsel: Add comments for booleans [new in V1]

Finally change map propagation so that system-wide events retain their cpus and
(dummy) threads:

perf tools: Allow system-wide events to keep their own CPUs
perf tools: Allow system-wide events to keep their own threads

Changes in V2:

Added some Acked-by: Ian Rogers <irogers@google.com>

libperf evsel: Add perf_evsel__enable_thread()
Use perf_cpu_map__for_each_cpu()

perf auxtrace: Add mmap_needed to auxtrace_mmap_params
Add documentation comment for mmap_needed

perf auxtrace: Remove auxtrace_mmap_params__set_idx() per_cpu parameter
Fix missing auxtrace_mmap_params__set_idx change

libperf evlist: Check nr_mmaps is correct
Remove unused code

libperf evsel: Add comments for booleans
Amend comments

perf evlist: Add evlist__add_dummy_on_all_cpus()
Rename evlist__add_system_wide -> evlist__add_on_all_cpus
Changed patch subject accordingly

perf record: Use evlist__add_dummy_on_all_cpus() in record__config_text_poke()
Rename evlist__add_system_wide -> evlist__add_on_all_cpus
Changed patch subject accordingly

perf intel-pt: Use evlist__add_dummy_on_all_cpus() for switch tracking
Rename evlist__add_system_wide -> evlist__add_on_all_cpus
Changed patch subject accordingly

Changes in V1:

perf intel-pt: Add a test for system-wide side band
New patch

libperf evsel: Factor out perf_evsel__ioctl()
Dropped because it has been applied.

libperf evsel: Add perf_evsel__enable_thread()
Rename variable i -> idx

perf auxtrace: Do not mix up mmap idx
Rename variable cpu to cpu_map_idx

perf tools: Allow all_cpus to be a superset of user_requested_cpus
Add Acked-by: Ian Rogers <irogers@google.com>

libperf evlist: Allow mixing per-thread and per-cpu mmaps
Fix perf_evlist__nr_mmaps() calculation

libperf evlist: Check nr_mmaps is correct
New patch

libperf evsel: Add comments for booleans
New patch

perf tools: Allow system-wide events to keep their own CPUs
perf tools: Allow system-wide events to keep their own threads

Adrian Hunter (23):
perf intel-pt: Add a test for system-wide side band
libperf evsel: Add perf_evsel__enable_thread()
perf evlist: Use libperf functions in evlist__enable_event_idx()
perf auxtrace: Move evlist__enable_event_idx() to auxtrace.c
perf auxtrace: Do not mix up mmap idx
libperf evlist: Remove ->idx() per_cpu parameter
libperf evlist: Move ->idx() into mmap_per_evsel()
libperf evlist: Add evsel as a parameter to ->idx()
perf auxtrace: Record whether an auxtrace mmap is needed
perf auxtrace: Add mmap_needed to auxtrace_mmap_params
perf auxtrace: Remove auxtrace_mmap_params__set_idx() per_cpu parameter
perf evlist: Factor out evlist__dummy_event()
perf evlist: Add evlist__add_dummy_on_all_cpus()
perf record: Use evlist__add_dummy_on_all_cpus() in record__config_text_poke()
perf intel-pt: Use evlist__add_dummy_on_all_cpus() for switch tracking
perf intel-pt: Track sideband system-wide when needed
perf tools: Allow all_cpus to be a superset of user_requested_cpus
libperf evlist: Allow mixing per-thread and per-cpu mmaps
libperf evlist: Check nr_mmaps is correct
perf stat: Add requires_cpu flag for uncore
libperf evsel: Add comments for booleans
perf tools: Allow system-wide events to keep their own CPUs
perf tools: Allow system-wide events to keep their own threads

tools/lib/perf/evlist.c | 80 ++++++++++-------------
tools/lib/perf/evsel.c | 15 +++++
tools/lib/perf/include/internal/evlist.h | 3 +-
tools/lib/perf/include/internal/evsel.h | 10 +++
tools/lib/perf/include/perf/evsel.h | 1 +
tools/perf/arch/arm/util/cs-etm.c | 1 +
tools/perf/arch/arm64/util/arm-spe.c | 1 +
tools/perf/arch/s390/util/auxtrace.c | 1 +
tools/perf/arch/x86/util/intel-bts.c | 1 +
tools/perf/arch/x86/util/intel-pt.c | 32 ++++------
tools/perf/builtin-record.c | 39 +++++-------
tools/perf/builtin-stat.c | 5 +-
tools/perf/tests/shell/test_intel_pt.sh | 71 +++++++++++++++++++++
tools/perf/util/auxtrace.c | 31 +++++++--
tools/perf/util/auxtrace.h | 10 +--
tools/perf/util/evlist.c | 106 +++++++++++++++----------------
tools/perf/util/evlist.h | 7 +-
tools/perf/util/evsel.c | 1 +
tools/perf/util/evsel.h | 1 +
tools/perf/util/mmap.c | 4 +-
tools/perf/util/parse-events.c | 2 +-
21 files changed, 261 insertions(+), 161 deletions(-)
create mode 100755 tools/perf/tests/shell/test_intel_pt.sh

Regards
Adrian