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SubjectRe: [PATCH v3 3/3] perf tools: Enable on a list of CPUs for hybrid
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Hi Jiri,

On 7/20/2021 3:36 AM, Jiri Olsa wrote:
> On Mon, Jul 12, 2021 at 03:12:35PM +0800, Jin Yao wrote:
>> The perf-record and perf-stat have supported the option '-C/--cpus'
>> to count or collect only on the list of CPUs provided. This option
>> needs to be supported for hybrid as well.
>>
>> For hybrid support, it needs to check that the CPUs are available on
>> hybrid PMU. One example for AlderLake, cpu0-7 is 'cpu_core', cpu8-11
>> is 'cpu_atom'.
>>
>> Before:
>>
>> # perf stat -e cpu_core/cycles/ -C11 -- sleep 1
>>
>> Performance counter stats for 'CPU(s) 11':
>>
>> <not supported> cpu_core/cycles/
>>
>> 1.006179431 seconds time elapsed
>>
>> The perf-stat silently returned "<not supported>" without any helpful
>> information. It should error out that cpu11 was not 'cpu_core'.
>>
>> After:
>>
>> # perf stat -e cpu_core/cycles/ -C11 -- sleep 1
>> WARNING: 11 isn't a 'cpu_core', please use a CPU list in the 'cpu_core' range (0-7)
>> failed to use cpu list 11
>>
>> We also need to support the events without pmu prefix specified.
>>
>> # perf stat -e cycles -C11 -- sleep 1
>> WARNING: 11 isn't a 'cpu_core', please use a CPU list in the 'cpu_core' range (0-7)
>>
>> Performance counter stats for 'CPU(s) 11':
>>
>> 1,067,373 cpu_atom/cycles/
>>
>> 1.005544738 seconds time elapsed
>>
>> The perf tool creates two cycles events automatically, cpu_core/cycles/ and
>> cpu_atom/cycles/. It checks that cpu11 is not 'cpu_core', then shows a warning
>> for cpu_core/cycles/ and only count the cpu_atom/cycles/.
>>
>> If part of cpus are 'cpu_core' and part of cpus are 'cpu_atom', the example,
>>
>> # perf stat -e cycles -C0,11 -- sleep 1
>> WARNING: use 0 in 'cpu_core' for 'cycles', skip other cpus in list.
>> WARNING: use 11 in 'cpu_atom' for 'cycles', skip other cpus in list.
>>
>> Performance counter stats for 'CPU(s) 0,11':
>>
>> 1,914,704 cpu_core/cycles/
>> 2,036,983 cpu_atom/cycles/
>>
>> 1.005815641 seconds time elapsed
>>
>> It now automatically selects cpu0 for cpu_core/cycles/, selects cpu11 for
>> cpu_atom/cycles/, and output with some warnings.
>>
>> Some more complex examples,
>>
>> # perf stat -e cycles,instructions -C0,11 -- sleep 1
>> WARNING: use 0 in 'cpu_core' for 'cycles', skip other cpus in list.
>> WARNING: use 11 in 'cpu_atom' for 'cycles', skip other cpus in list.
>> WARNING: use 0 in 'cpu_core' for 'instructions', skip other cpus in list.
>> WARNING: use 11 in 'cpu_atom' for 'instructions', skip other cpus in list.
>>
>> Performance counter stats for 'CPU(s) 0,11':
>>
>> 2,780,387 cpu_core/cycles/
>> 1,583,432 cpu_atom/cycles/
>> 3,957,277 cpu_core/instructions/
>> 1,167,089 cpu_atom/instructions/
>>
>> 1.006005124 seconds time elapsed
>>
>> # perf stat -e cycles,cpu_atom/instructions/ -C0,11 -- sleep 1
>> WARNING: use 0 in 'cpu_core' for 'cycles', skip other cpus in list.
>> WARNING: use 11 in 'cpu_atom' for 'cycles', skip other cpus in list.
>> WARNING: use 11 in 'cpu_atom' for 'cpu_atom/instructions/', skip other cpus in list.
>>
>> Performance counter stats for 'CPU(s) 0,11':
>>
>> 3,290,301 cpu_core/cycles/
>> 1,953,073 cpu_atom/cycles/
>> 1,407,869 cpu_atom/instructions/
>>
>> 1.006260912 seconds time elapsed
>>
>> Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
>> ---
>> v3:
>> - Rebase to perf/core.
>> - No functional change.
>>
>> v2:
>> - Automatically map to hybrid pmu.
>>
>> tools/perf/builtin-record.c | 7 ++++
>> tools/perf/builtin-stat.c | 6 +++
>> tools/perf/util/evlist-hybrid.c | 65 +++++++++++++++++++++++++++++++++
>> tools/perf/util/evlist-hybrid.h | 1 +
>> tools/perf/util/evlist.c | 1 +
>> tools/perf/util/pmu.c | 35 ++++++++++++++++++
>> tools/perf/util/pmu.h | 4 ++
>> 7 files changed, 119 insertions(+)
>>
>> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
>> index 671a21c9ee4d..9518b028b850 100644
>> --- a/tools/perf/builtin-record.c
>> +++ b/tools/perf/builtin-record.c
>> @@ -2884,6 +2884,13 @@ int cmd_record(int argc, const char **argv)
>> /* Enable ignoring missing threads when -u/-p option is defined. */
>> rec->opts.ignore_missing_thread = rec->opts.target.uid != UINT_MAX || rec->opts.target.pid;
>>
>> + if (evlist__use_cpu_list(rec->evlist, rec->opts.target.cpu_list)) {
>> + pr_err("failed to use cpu list %s\n",
>> + rec->opts.target.cpu_list);
>> + goto out;
>> + }
>> +
>> + rec->opts.target.hybrid = perf_pmu__has_hybrid();
>> err = -ENOMEM;
>> if (evlist__create_maps(rec->evlist, &rec->opts.target) < 0)
>> usage_with_options(record_usage, record_options);
>> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
>> index d25cb8088e8c..f7067587008f 100644
>> --- a/tools/perf/builtin-stat.c
>> +++ b/tools/perf/builtin-stat.c
>> @@ -2430,6 +2430,12 @@ int cmd_stat(int argc, const char **argv)
>> if ((stat_config.aggr_mode == AGGR_THREAD) && (target.system_wide))
>> target.per_thread = true;
>>
>> + if (evlist__use_cpu_list(evsel_list, target.cpu_list)) {
>> + pr_err("failed to use cpu list %s\n", target.cpu_list);
>> + goto out;
>> + }
>> +
>> + target.hybrid = perf_pmu__has_hybrid();
>> if (evlist__create_maps(evsel_list, &target) < 0) {
>> if (target__has_task(&target)) {
>> pr_err("Problems finding threads of monitor\n");
>> diff --git a/tools/perf/util/evlist-hybrid.c b/tools/perf/util/evlist-hybrid.c
>> index db3f5fbdebe1..13c9f3063dda 100644
>> --- a/tools/perf/util/evlist-hybrid.c
>> +++ b/tools/perf/util/evlist-hybrid.c
>> @@ -86,3 +86,68 @@ bool evlist__has_hybrid(struct evlist *evlist)
>>
>> return false;
>> }
>> +
>> +int evlist__use_cpu_list(struct evlist *evlist, const char *cpu_list)
>
>
> the name seems not to cover what it's doing, how about something
> like evlist__fix_cpus or such
>

OK, evlist__fix_cpus() is better, use this name in v4.

>> +{
>> + struct perf_cpu_map *cpus;
>> + struct evsel *evsel, *tmp;
>> + struct perf_pmu *pmu;
>> + int ret, unmatched_count = 0, events_nr = 0;
>> +
>> + if (!perf_pmu__has_hybrid() || !cpu_list)
>> + return 0;
>> +
>> + cpus = perf_cpu_map__new(cpu_list);
>> + if (!cpus)
>> + return -1;
>> +
>> + evlist__for_each_entry_safe(evlist, tmp, evsel) {
>> + struct perf_cpu_map *matched_cpus, *unmatched_cpus;
>> + char buf1[128], buf2[128];
>> +
>> + pmu = perf_pmu__find_hybrid_pmu(evsel->pmu_name);
>> + if (!pmu)
>> + continue;
>> +
>> + ret = perf_pmu__cpus_match(pmu, cpus, &matched_cpus,
>> + &unmatched_cpus);
>> + if (ret)
>> + goto out;
>> +
>> + events_nr++;
>> +
>> + if (matched_cpus->nr > 0 && (unmatched_cpus->nr > 0 ||
>> + matched_cpus->nr < cpus->nr ||
>> + matched_cpus->nr < pmu->cpus->nr)) {
>> + perf_cpu_map__put(evsel->core.cpus);
>> + perf_cpu_map__put(evsel->core.own_cpus);
>> + evsel->core.cpus = perf_cpu_map__get(matched_cpus);
>> + evsel->core.own_cpus = perf_cpu_map__get(matched_cpus);
>
> I'm bit confused in here.. AFAIUI there's 2 evsel objects create
> for hybrid 'cycles' ... should they have already proper cpus set?
>

For 'cycles', yes two evsels are created automatically. One is for atom CPU (e.g. 8-11), the other
is for core CPU (e.g. 0-7). In this example, these 2 evsels have already the cpus set.

While the 'cpus' here is just the user specified cpu list.
cpus = perf_cpu_map__new(cpu_list);

We need to check that the cpu in 'cpus' is available on hybrid pmu or not and adjust the
evsel->core.cpus according the matching results.

>> +
>> + if (unmatched_cpus->nr > 0) {
>> + cpu_map__snprint(matched_cpus, buf1, sizeof(buf1));
>> + pr_warning("WARNING: use %s in '%s' for '%s', skip other cpus in list.\n",
>> + buf1, pmu->name, evsel->name);
>> + }
>> + }
>> +
>> + if (matched_cpus->nr == 0) {
>> + evlist__remove(evlist, evsel);
>> + evsel__delete(evsel);
>> +
>> + cpu_map__snprint(cpus, buf1, sizeof(buf1));
>> + cpu_map__snprint(pmu->cpus, buf2, sizeof(buf2));
>> + pr_warning("WARNING: %s isn't a '%s', please use a CPU list in the '%s' range (%s)\n",
>> + buf1, pmu->name, pmu->name, buf2);
>> + unmatched_count++;
>> + }
>
> hum, should we rather fail in here?
>

perf stat -e cpu_core/cycles/,cpu_atom/instructions/ -C11

CPU11 is atom CPU so the evsel 'cpu_core/cycles/' is failed but cpu_atom/instructions/ is OK.

Don't we report the partially successful event?

Thanks
Jin Yao

> jirka
>

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