Re: [PATCH 4/5] perf parse-events: Specially handle uncore event alias in small groups

["Liang, Kan" <kan.liang@linux.intel.com>]

On 4/24/2018 3:17 PM, Arnaldo Carvalho de Melo wrote:
> Em Tue, Apr 24, 2018 at 11:20:13AM -0700, kan.liang@linux.intel.com escreveu:
>> From: Kan Liang <kan.liang@linux.intel.com>
>>
>> Perf stat doesn't count the uncore event aliases from the same uncore
>> block in a group, for example:
> 
> This one is not applying to acme/perf/urgent, all the rest I got merged
> there, the last one with that change from using strstr() to a new bool
> in perf_evsel for the uniquifying operation having being performed.
>

Sure. Thank you for letting me know.

Thanks,
Kan

> - Arnaldo
>   
>>    perf stat -e '{unc_m_cas_count.all,unc_m_clockticks}' -a -I 1000
>>    #           time             counts unit events
>>         1.000447342      <not counted>      unc_m_cas_count.all
>>         1.000447342      <not counted>      unc_m_clockticks
>>         2.000740654      <not counted>      unc_m_cas_count.all
>>         2.000740654      <not counted>      unc_m_clockticks
>>
>> The output is very misleading. It gives a wrong impression that the
>> uncore event doesn't work.
>>
>> An uncore block could be composed by several PMUs. An uncore event alias
>> is a joint name which means the same event runs on all PMUs of a block.
>> Perf doesn't support mixed events from different PMUs in the same group.
>> It is wrong to put uncore event aliases in a big group.
>>
>> The right way is to split the big group into multiple small groups which
>> only include the events from the same PMU.
>> Only uncore event aliases from the same uncore block should be specially
>> handled here. It doesn't make sense to mix the uncore events with other
>> uncore events from different blocks or even core events in a group.
>>
>> With the patch:
>>    #           time             counts unit events
>>       1.001557653            140,833      unc_m_cas_count.all
>>       1.001557653      1,330,231,332      unc_m_clockticks
>>       2.002709483             85,007      unc_m_cas_count.all
>>       2.002709483      1,429,494,563      unc_m_clockticks
>>
>> Reported-by: Andi Kleen <ak@linux.intel.com>
>> Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
>> ---
>>   tools/perf/util/evsel.h        |  1 +
>>   tools/perf/util/parse-events.c | 94 ++++++++++++++++++++++++++++++++++++++++--
>>   tools/perf/util/parse-events.h |  7 +++-
>>   tools/perf/util/parse-events.y |  8 ++--
>>   4 files changed, 101 insertions(+), 9 deletions(-)
>>
>> diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
>> index d3ee3af..b8a1055 100644
>> --- a/tools/perf/util/evsel.h
>> +++ b/tools/perf/util/evsel.h
>> @@ -126,6 +126,7 @@ struct perf_evsel {
>>   	bool			precise_max;
>>   	bool			ignore_missing_thread;
>>   	bool			forced_leader;
>> +	bool			use_uncore_alias;
>>   	/* parse modifier helper */
>>   	int			exclude_GH;
>>   	int			nr_members;
>> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
>> index 2fb0272..7a836fe 100644
>> --- a/tools/perf/util/parse-events.c
>> +++ b/tools/perf/util/parse-events.c
>> @@ -1219,13 +1219,16 @@ int parse_events_add_numeric(struct parse_events_state *parse_state,
>>   
>>   int parse_events_add_pmu(struct parse_events_state *parse_state,
>>   			 struct list_head *list, char *name,
>> -			 struct list_head *head_config, bool auto_merge_stats)
>> +			 struct list_head *head_config,
>> +			 bool auto_merge_stats,
>> +			 bool use_alias)
>>   {
>>   	struct perf_event_attr attr;
>>   	struct perf_pmu_info info;
>>   	struct perf_pmu *pmu;
>>   	struct perf_evsel *evsel;
>>   	struct parse_events_error *err = parse_state->error;
>> +	bool use_uncore_alias;
>>   	LIST_HEAD(config_terms);
>>   
>>   	pmu = perf_pmu__find(name);
>> @@ -1244,11 +1247,14 @@ int parse_events_add_pmu(struct parse_events_state *parse_state,
>>   		memset(&attr, 0, sizeof(attr));
>>   	}
>>   
>> +	use_uncore_alias = (pmu->is_uncore && use_alias);
>> +
>>   	if (!head_config) {
>>   		attr.type = pmu->type;
>>   		evsel = __add_event(list, &parse_state->idx, &attr, NULL, pmu, NULL, auto_merge_stats);
>>   		if (evsel) {
>>   			evsel->pmu_name = name;
>> +			evsel->use_uncore_alias = use_uncore_alias;
>>   			return 0;
>>   		} else {
>>   			return -ENOMEM;
>> @@ -1282,6 +1288,7 @@ int parse_events_add_pmu(struct parse_events_state *parse_state,
>>   		evsel->metric_expr = info.metric_expr;
>>   		evsel->metric_name = info.metric_name;
>>   		evsel->pmu_name = name;
>> +		evsel->use_uncore_alias = use_uncore_alias;
>>   	}
>>   
>>   	return evsel ? 0 : -ENOMEM;
>> @@ -1317,7 +1324,7 @@ int parse_events_multi_pmu_add(struct parse_events_state *parse_state,
>>   				list_add_tail(&term->list, head);
>>   
>>   				if (!parse_events_add_pmu(parse_state, list,
>> -							  pmu->name, head, true)) {
>> +							  pmu->name, head, true, true)) {
>>   					pr_debug("%s -> %s/%s/\n", str,
>>   						 pmu->name, alias->str);
>>   					ok++;
>> @@ -1339,7 +1346,85 @@ int parse_events__modifier_group(struct list_head *list,
>>   	return parse_events__modifier_event(list, event_mod, true);
>>   }
>>   
>> -void parse_events__set_leader(char *name, struct list_head *list)
>> +/*
>> + * Check if the two uncore PMUs are from the same uncore block
>> + * The format of the uncore PMU name is uncore_#blockname_#pmuidx
>> + */
>> +static bool is_same_uncore_block(const char *pmu_name_a, const char *pmu_name_b)
>> +{
>> +	char *end_a, *end_b;
>> +
>> +	end_a = strrchr(pmu_name_a, '_');
>> +	end_b = strrchr(pmu_name_b, '_');
>> +
>> +	if (!end_a || !end_b)
>> +		return false;
>> +
>> +	if ((end_a - pmu_name_a) != (end_b - pmu_name_b))
>> +		return false;
>> +
>> +	return (0 == strncmp(pmu_name_a, pmu_name_b, end_a - pmu_name_a));
>> +}
>> +
>> +static int
>> +parse_events__set_leader_for_uncore_aliase(char *name, struct list_head *list,
>> +					   struct parse_events_state *parse_state)
>> +{
>> +	struct perf_evsel *evsel, *leader;
>> +	uintptr_t *leaders;
>> +	int i = 0, nr_pmu = 0, total_members, ret = 0;
>> +
>> +	leader = list_entry(list->next, struct perf_evsel, node);
>> +	evsel = list_entry(list->prev, struct perf_evsel, node);
>> +	total_members = evsel->idx - leader->idx + 1;
>> +
>> +	leaders = calloc(total_members, sizeof(uintptr_t));
>> +	if (!leaders)
>> +		return ret;
>> +
>> +	 __evlist__for_each_entry(list, evsel) {
>> +
>> +		/* Only split the uncore group which members use alias */
>> +		if (!evsel->use_uncore_alias)
>> +			goto out;
>> +
>> +		/* The events must be from the same uncore block */
>> +		if (!is_same_uncore_block(leader->pmu_name, evsel->pmu_name))
>> +			goto out;
>> +
>> +		if (!strcmp(leader->name, evsel->name))
>> +			leaders[nr_pmu++] = (uintptr_t) evsel;
>> +	}
>> +
>> +	/* only one event alias */
>> +	if (nr_pmu == total_members) {
>> +		parse_state->nr_groups--;
>> +		goto handled;
>> +	}
>> +
>> +	__evlist__for_each_entry(list, evsel) {
>> +		if (i >= nr_pmu)
>> +			i = 0;
>> +		evsel->leader = (struct perf_evsel *) leaders[i++];
>> +	}
>> +
>> +	for (i = 0; i < nr_pmu; i++) {
>> +		evsel = (struct perf_evsel *) leaders[i];
>> +		evsel->nr_members = total_members / nr_pmu;
>> +		evsel->group_name = name ? strdup(name) : NULL;
>> +	}
>> +
>> +	parse_state->nr_groups += nr_pmu - 1;
>> +
>> +handled:
>> +	ret = 1;
>> +out:
>> +	free(leaders);
>> +	return ret;
>> +}
>> +
>> +void parse_events__set_leader(char *name, struct list_head *list,
>> +			      struct parse_events_state *parse_state)
>>   {
>>   	struct perf_evsel *leader;
>>   
>> @@ -1348,6 +1433,9 @@ void parse_events__set_leader(char *name, struct list_head *list)
>>   		return;
>>   	}
>>   
>> +	if (parse_events__set_leader_for_uncore_aliase(name, list, parse_state))
>> +		return;
>> +
>>   	__perf_evlist__set_leader(list);
>>   	leader = list_entry(list->next, struct perf_evsel, node);
>>   	leader->group_name = name ? strdup(name) : NULL;
>> diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
>> index 5015cfd..4473dac 100644
>> --- a/tools/perf/util/parse-events.h
>> +++ b/tools/perf/util/parse-events.h
>> @@ -167,7 +167,9 @@ int parse_events_add_breakpoint(struct list_head *list, int *idx,
>>   				void *ptr, char *type, u64 len);
>>   int parse_events_add_pmu(struct parse_events_state *parse_state,
>>   			 struct list_head *list, char *name,
>> -			 struct list_head *head_config, bool auto_merge_stats);
>> +			 struct list_head *head_config,
>> +			 bool auto_merge_stats,
>> +			 bool use_alias);
>>   
>>   int parse_events_multi_pmu_add(struct parse_events_state *parse_state,
>>   			       char *str,
>> @@ -178,7 +180,8 @@ int parse_events_copy_term_list(struct list_head *old,
>>   
>>   enum perf_pmu_event_symbol_type
>>   perf_pmu__parse_check(const char *name);
>> -void parse_events__set_leader(char *name, struct list_head *list);
>> +void parse_events__set_leader(char *name, struct list_head *list,
>> +			      struct parse_events_state *parse_state);
>>   void parse_events_update_lists(struct list_head *list_event,
>>   			       struct list_head *list_all);
>>   void parse_events_evlist_error(struct parse_events_state *parse_state,
>> diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
>> index 7afeb80..e37608a 100644
>> --- a/tools/perf/util/parse-events.y
>> +++ b/tools/perf/util/parse-events.y
>> @@ -161,7 +161,7 @@ PE_NAME '{' events '}'
>>   	struct list_head *list = $3;
>>   
>>   	inc_group_count(list, _parse_state);
>> -	parse_events__set_leader($1, list);
>> +	parse_events__set_leader($1, list, _parse_state);
>>   	$$ = list;
>>   }
>>   |
>> @@ -170,7 +170,7 @@ PE_NAME '{' events '}'
>>   	struct list_head *list = $2;
>>   
>>   	inc_group_count(list, _parse_state);
>> -	parse_events__set_leader(NULL, list);
>> +	parse_events__set_leader(NULL, list, _parse_state);
>>   	$$ = list;
>>   }
>>   
>> @@ -232,7 +232,7 @@ PE_NAME opt_event_config
>>   		YYABORT;
>>   
>>   	ALLOC_LIST(list);
>> -	if (parse_events_add_pmu(_parse_state, list, $1, $2, false)) {
>> +	if (parse_events_add_pmu(_parse_state, list, $1, $2, false, false)) {
>>   		struct perf_pmu *pmu = NULL;
>>   		int ok = 0;
>>   		char *pattern;
>> @@ -251,7 +251,7 @@ PE_NAME opt_event_config
>>   					free(pattern);
>>   					YYABORT;
>>   				}
>> -				if (!parse_events_add_pmu(_parse_state, list, pmu->name, terms, true))
>> +				if (!parse_events_add_pmu(_parse_state, list, pmu->name, terms, true, false))
>>   					ok++;
>>   				parse_events_terms__delete(terms);
>>   			}
>> -- 
>> 2.7.4