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Date: Wed, 31 Jan 2024 18:12:45 -0800
From: Ian Rogers <irogers@...gle.com>
To: James Clark <james.clark@....com>
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>, Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>,
Namhyung Kim <namhyung@...nel.org>, Adrian Hunter <adrian.hunter@...el.com>,
Suzuki K Poulose <suzuki.poulose@....com>, Mike Leach <mike.leach@...aro.org>,
John Garry <john.g.garry@...cle.com>, Will Deacon <will@...nel.org>,
Thomas Gleixner <tglx@...utronix.de>, Darren Hart <dvhart@...radead.org>,
Davidlohr Bueso <dave@...olabs.net>, André Almeida <andrealmeid@...lia.com>,
Kan Liang <kan.liang@...ux.intel.com>, K Prateek Nayak <kprateek.nayak@....com>,
Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>,
Kajol Jain <kjain@...ux.ibm.com>, Athira Rajeev <atrajeev@...ux.vnet.ibm.com>,
Andrew Jones <ajones@...tanamicro.com>, Alexandre Ghiti <alexghiti@...osinc.com>,
Atish Patra <atishp@...osinc.com>, "Steinar H. Gunderson" <sesse@...gle.com>,
Yang Jihong <yangjihong1@...wei.com>, Yang Li <yang.lee@...ux.alibaba.com>,
Changbin Du <changbin.du@...wei.com>, Sandipan Das <sandipan.das@....com>,
Ravi Bangoria <ravi.bangoria@....com>, Paran Lee <p4ranlee@...il.com>,
Nick Desaulniers <ndesaulniers@...gle.com>, Huacai Chen <chenhuacai@...nel.org>,
Yanteng Si <siyanteng@...ngson.cn>, linux-perf-users@...r.kernel.org,
linux-kernel@...r.kernel.org, coresight@...ts.linaro.org,
linux-arm-kernel@...ts.infradead.org, bpf@...r.kernel.org,
Leo Yan <leo.yan@...aro.org>
Subject: Re: [PATCH v1 07/14] perf arm-spe/cs-etm: Directly iterate CPU maps
On Tue, Dec 12, 2023 at 6:36 AM James Clark <james.clark@....com> wrote:
>
>
>
> On 12/12/2023 14:17, James Clark wrote:
> >
> >
> > On 29/11/2023 06:02, Ian Rogers wrote:
> >> Rather than iterate all CPUs and see if they are in CPU maps, directly
> >> iterate the CPU map. Similarly make use of the intersect
> >> function. Switch perf_cpu_map__has_any_cpu_or_is_empty to more
> >> appropriate alternatives.
> >>
> >> Signed-off-by: Ian Rogers <irogers@...gle.com>
> >> ---
> >> tools/perf/arch/arm/util/cs-etm.c | 77 ++++++++++++----------------
> >> tools/perf/arch/arm64/util/arm-spe.c | 4 +-
> >> 2 files changed, 34 insertions(+), 47 deletions(-)
> >>
> >> diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c
> >> index 77e6663c1703..a68a72f2f668 100644
> >> --- a/tools/perf/arch/arm/util/cs-etm.c
> >> +++ b/tools/perf/arch/arm/util/cs-etm.c
> >> @@ -197,38 +197,32 @@ static int cs_etm_validate_timestamp(struct auxtrace_record *itr,
> >> static int cs_etm_validate_config(struct auxtrace_record *itr,
> >> struct evsel *evsel)
> >> {
> >> - int i, err = -EINVAL;
> >> + int idx, err = -EINVAL;
> >> struct perf_cpu_map *event_cpus = evsel->evlist->core.user_requested_cpus;
> >> struct perf_cpu_map *online_cpus = perf_cpu_map__new_online_cpus();
> >> + struct perf_cpu_map *intersect_cpus = perf_cpu_map__intersect(event_cpus, online_cpus);
> >> + struct perf_cpu cpu;
> >>
> >> - /* Set option of each CPU we have */
> >> - for (i = 0; i < cpu__max_cpu().cpu; i++) {
> >> - struct perf_cpu cpu = { .cpu = i, };
> >> -
> >> - /*
> >> - * In per-cpu case, do the validation for CPUs to work with.
> >> - * In per-thread case, the CPU map is empty. Since the traced
> >> - * program can run on any CPUs in this case, thus don't skip
> >> - * validation.
> >> - */
> >> - if (!perf_cpu_map__has_any_cpu_or_is_empty(event_cpus) &&
> >> - !perf_cpu_map__has(event_cpus, cpu))
> >> - continue;
> >
> > This has broken validation for per-thread sessions.
> > perf_cpu_map__intersect() doesn't seem to be able to handle the case
> > where an 'any' map intersected with an online map should return the
> > online map. Or at least it should for this to work, and it seems to make
> > sense for it to work that way.
> >
> > At least that was my initial impression, but I only debugged it and saw
> > that the loop is now skipped entirely.
> >
> >> -
> >> - if (!perf_cpu_map__has(online_cpus, cpu))
> >> - continue;
> >> + perf_cpu_map__put(online_cpus);
> >>
> >> - err = cs_etm_validate_context_id(itr, evsel, i);
> >> + /*
> >> + * Set option of each CPU we have. In per-cpu case, do the validation
> >> + * for CPUs to work with. In per-thread case, the CPU map is empty.
> >> + * Since the traced program can run on any CPUs in this case, thus don't
> >> + * skip validation.
> >> + */
> >> + perf_cpu_map__for_each_cpu_skip_any(cpu, idx, intersect_cpus) {
> >> + err = cs_etm_validate_context_id(itr, evsel, cpu.cpu);
> >> if (err)
> >> goto out;
> >> - err = cs_etm_validate_timestamp(itr, evsel, i);
> >> + err = cs_etm_validate_timestamp(itr, evsel, idx);
I think this is an error, idx shouldn't be used here, cpu.cpu should.
> >> if (err)
> >> goto out;
> >> }
> >>
> >> err = 0;
> >> out:
> >> - perf_cpu_map__put(online_cpus);
> >> + perf_cpu_map__put(intersect_cpus);
> >> return err;
> >> }
> >>
> >> @@ -435,7 +429,7 @@ static int cs_etm_recording_options(struct auxtrace_record *itr,
> >> * Also the case of per-cpu mmaps, need the contextID in order to be notified
> >> * when a context switch happened.
> >> */
> >> - if (!perf_cpu_map__has_any_cpu_or_is_empty(cpus)) {
> >> + if (!perf_cpu_map__is_any_cpu_or_is_empty(cpus)) {
> >> evsel__set_config_if_unset(cs_etm_pmu, cs_etm_evsel,
> >> "timestamp", 1);
> >> evsel__set_config_if_unset(cs_etm_pmu, cs_etm_evsel,
> >> @@ -461,7 +455,7 @@ static int cs_etm_recording_options(struct auxtrace_record *itr,
> >> evsel->core.attr.sample_period = 1;
> >>
> >> /* In per-cpu case, always need the time of mmap events etc */
> >> - if (!perf_cpu_map__has_any_cpu_or_is_empty(cpus))
> >> + if (!perf_cpu_map__is_any_cpu_or_is_empty(cpus))
> >> evsel__set_sample_bit(evsel, TIME);
> >>
> >> err = cs_etm_validate_config(itr, cs_etm_evsel);
> >> @@ -533,38 +527,32 @@ static size_t
> >> cs_etm_info_priv_size(struct auxtrace_record *itr __maybe_unused,
> >> struct evlist *evlist __maybe_unused)
> >> {
> >> - int i;
> >> + int idx;
> >> int etmv3 = 0, etmv4 = 0, ete = 0;
> >> struct perf_cpu_map *event_cpus = evlist->core.user_requested_cpus;
> >> struct perf_cpu_map *online_cpus = perf_cpu_map__new_online_cpus();
> >> + struct perf_cpu cpu;
> >>
> >> /* cpu map is not empty, we have specific CPUs to work with */
> >> - if (!perf_cpu_map__has_any_cpu_or_is_empty(event_cpus)) {
> >> - for (i = 0; i < cpu__max_cpu().cpu; i++) {
> >> - struct perf_cpu cpu = { .cpu = i, };
> >> -
> >> - if (!perf_cpu_map__has(event_cpus, cpu) ||
> >> - !perf_cpu_map__has(online_cpus, cpu))
> >> - continue;
> >> + if (!perf_cpu_map__is_empty(event_cpus)) {
> >> + struct perf_cpu_map *intersect_cpus =
> >> + perf_cpu_map__intersect(event_cpus, online_cpus);
> >>
> >> - if (cs_etm_is_ete(itr, i))
> >> + perf_cpu_map__for_each_cpu_skip_any(cpu, idx, intersect_cpus) {
> >> + if (cs_etm_is_ete(itr, cpu.cpu))
>
> Similar problem here. For a per-thread session, the CPU map is not empty
> (it's an 'any' map, presumably length 1), so it comes into this first
> if, rather than the else below which is for the 'any' scenario.
>
> Then the intersect with online CPUs results in an empty map, so no CPU
> metadata is recorded, then the session fails.
>
> If you made the intersect work in the way I mentioned above we could
> also delete the else below, because that's just another way to convert
> from 'any' to 'all online'.
I don't think intersect of "all online" with an "any CPU" should
return "all online" as these would be quite different options to
perf_event_open. Let's see if the issue above fixes this change
otherwise I can revert it to a more mechanical translation of the
existing code into the new APIs.
Thanks,
Ian
> >> ete++;
> >> - else if (cs_etm_is_etmv4(itr, i))
> >> + else if (cs_etm_is_etmv4(itr, cpu.cpu))
> >> etmv4++;
> >> else
> >> etmv3++;
> >> }
> >> + perf_cpu_map__put(intersect_cpus);
> >> } else {
> >> /* get configuration for all CPUs in the system */
> >> - for (i = 0; i < cpu__max_cpu().cpu; i++) {
> >> - struct perf_cpu cpu = { .cpu = i, };
> >> -
> >> - if (!perf_cpu_map__has(online_cpus, cpu))
> >> - continue;
> >> -
> >> - if (cs_etm_is_ete(itr, i))
> >> + perf_cpu_map__for_each_cpu(cpu, idx, online_cpus) {
> >> + if (cs_etm_is_ete(itr, cpu.cpu))
> >> ete++;
> >> - else if (cs_etm_is_etmv4(itr, i))
> >> + else if (cs_etm_is_etmv4(itr, cpu.cpu))
> >> etmv4++;
> >> else
> >> etmv3++;
> >> @@ -814,15 +802,14 @@ static int cs_etm_info_fill(struct auxtrace_record *itr,
> >> return -EINVAL;
> >>
> >> /* If the cpu_map is empty all online CPUs are involved */
> >> - if (perf_cpu_map__has_any_cpu_or_is_empty(event_cpus)) {
> >> + if (perf_cpu_map__is_empty(event_cpus)) {
> >> cpu_map = online_cpus;
> >> } else {
> >> /* Make sure all specified CPUs are online */
> >> - for (i = 0; i < perf_cpu_map__nr(event_cpus); i++) {
> >> - struct perf_cpu cpu = { .cpu = i, };
> >> + struct perf_cpu cpu;
> >>
> >> - if (perf_cpu_map__has(event_cpus, cpu) &&
> >> - !perf_cpu_map__has(online_cpus, cpu))
> >> + perf_cpu_map__for_each_cpu(cpu, i, event_cpus) {
> >> + if (!perf_cpu_map__has(online_cpus, cpu))
> >> return -EINVAL;
> >> }
> >>
> >> diff --git a/tools/perf/arch/arm64/util/arm-spe.c b/tools/perf/arch/arm64/util/arm-spe.c
> >> index 51ccbfd3d246..0b52e67edb3b 100644
> >> --- a/tools/perf/arch/arm64/util/arm-spe.c
> >> +++ b/tools/perf/arch/arm64/util/arm-spe.c
> >> @@ -232,7 +232,7 @@ static int arm_spe_recording_options(struct auxtrace_record *itr,
> >> * In the case of per-cpu mmaps, sample CPU for AUX event;
> >> * also enable the timestamp tracing for samples correlation.
> >> */
> >> - if (!perf_cpu_map__has_any_cpu_or_is_empty(cpus)) {
> >> + if (!perf_cpu_map__is_any_cpu_or_is_empty(cpus)) {
> >> evsel__set_sample_bit(arm_spe_evsel, CPU);
> >> evsel__set_config_if_unset(arm_spe_pmu, arm_spe_evsel,
> >> "ts_enable", 1);
> >> @@ -265,7 +265,7 @@ static int arm_spe_recording_options(struct auxtrace_record *itr,
> >> tracking_evsel->core.attr.sample_period = 1;
> >>
> >> /* In per-cpu case, always need the time of mmap events etc */
> >> - if (!perf_cpu_map__has_any_cpu_or_is_empty(cpus)) {
> >> + if (!perf_cpu_map__is_any_cpu_or_is_empty(cpus)) {
> >> evsel__set_sample_bit(tracking_evsel, TIME);
> >> evsel__set_sample_bit(tracking_evsel, CPU);
> >>
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