linux-kernel - Re: [PATCH v4 12/25] perf parse-events: Support event inside hybrid pmu

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Date:   Thu, 22 Apr 2021 09:44:07 +0800
From:   "Jin, Yao" <yao.jin@...ux.intel.com>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     acme@...nel.org, jolsa@...nel.org, peterz@...radead.org,
        mingo@...hat.com, alexander.shishkin@...ux.intel.com,
        Linux-kernel@...r.kernel.org, ak@...ux.intel.com,
        kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH v4 12/25] perf parse-events: Support event inside hybrid
 pmu

Hi Jiri,

On 4/22/2021 2:29 AM, Jiri Olsa wrote:
> On Fri, Apr 16, 2021 at 10:05:04PM +0800, Jin Yao wrote:
> 
> SNIP
> 
>> ---
>> v4:
>>   - New in v4.
>>
>>   tools/perf/util/parse-events.c | 55 ++++++++++++++++++++++++++++++++++
>>   1 file changed, 55 insertions(+)
>>
>> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
>> index f69475a158bb..bd3fd722b4ac 100644
>> --- a/tools/perf/util/parse-events.c
>> +++ b/tools/perf/util/parse-events.c
>> @@ -38,6 +38,7 @@
>>   #include "util/event.h"
>>   #include "util/pfm.h"
>>   #include "util/parse-events-hybrid.h"
>> +#include "util/pmu-hybrid.h"
>>   #include "perf.h"
>>   
>>   #define MAX_NAME_LEN 100
>> @@ -48,6 +49,9 @@ extern int parse_events_debug;
>>   int parse_events_parse(void *parse_state, void *scanner);
>>   static int get_config_terms(struct list_head *head_config,
>>   			    struct list_head *head_terms __maybe_unused);
>> +static int parse_events__with_hybrid_pmu(struct parse_events_state *parse_state,
>> +					 const char *str, char *pmu_name,
>> +					 struct list_head *list, bool *parsed);
>>   
>>   static struct perf_pmu_event_symbol *perf_pmu_events_list;
>>   /*
>> @@ -1567,6 +1571,27 @@ int parse_events_add_pmu(struct parse_events_state *parse_state,
>>   	if (pmu->default_config && get_config_chgs(pmu, head_config, &config_terms))
>>   		return -ENOMEM;
>>   
>> +	if (!parse_state->fake_pmu && head_config &&
>> +	    perf_pmu__is_hybrid(name)) {
>> +		struct parse_events_term *term;
>> +		bool parsed;
>> +		int ret;
>> +
>> +		term = list_first_entry(head_config, struct parse_events_term,
>> +					list);
> 
> you need to test that there's something in the head_config first,
> and I thought you wanted to check that there's just 1 term, right?
> (you could check the next pointer == head_config)
> 

Yes, agree, we need to check the head_config has only one term first. Otherwise we don't need to do 
the second parsing.

> also please move this to separated function
>

OK.

>> +		if (term && term->config && strcmp(term->config, "event")) {
>> +			ret = parse_events__with_hybrid_pmu(parse_state,
>> +							    term->config, name,
>> +							    list, &parsed);
>> +			/*
>> +			 * If the string inside the pmu can't be parsed,
>> +			 * don't return, try next steps.
>> +			 */
>> +			if (parsed)
>> +				return ret;
> 
> so if the function fails we ignore the return value,
> because parsed is set only for ret == 0, so I think we
> don't need 'parsed' param and we could make parse_events__with_hybrid_pmu
> return 0 when we found some event and let it go through otherwise
> 

That makes sense. We let the parse_events__with_hybrid_pmu just returns 0 when we can find some 
events in second parsing. If there are no events parsed or something error occurs, 
parse_events__with_hybrid_pmu returns error value then we can go through other cases.

> 
>> +		}
>> +	}
>> +
>>   	if (!parse_state->fake_pmu && perf_pmu__config(pmu, &attr, head_config, parse_state->error)) {
>>   		struct evsel_config_term *pos, *tmp;
>>   
>> @@ -1585,6 +1610,9 @@ int parse_events_add_pmu(struct parse_events_state *parse_state,
>>   	if (!evsel)
>>   		return -ENOMEM;
>>   
>> +	if (evsel->name)
>> +		evsel->use_config_name = true;
> 
> should this go to:
>   perf stat: Uniquify hybrid event name
> ?
> 

OK, I will move this to patch "perf stat: Uniquify hybrid event name".

> thanks,
> jirka
>

Thanks
Jin Yao

>> +
>>   	evsel->pmu_name = name ? strdup(name) : NULL;
>>   	evsel->use_uncore_alias = use_uncore_alias;
>>   	evsel->percore = config_term_percore(&evsel->config_terms);
>> @@ -2180,6 +2208,33 @@ int parse_events_terms(struct list_head *terms, const char *str)
>>   	return ret;
>>   }
>>   
>> +static int parse_events__with_hybrid_pmu(struct parse_events_state *parse_state,
>> +					 const char *str, char *pmu_name,
>> +					 struct list_head *list, bool *parsed)
>> +{
>> +	struct parse_events_state ps = {
>> +		.list            = LIST_HEAD_INIT(ps.list),
>> +		.stoken          = PE_START_EVENTS,
>> +		.hybrid_pmu_name = pmu_name,
>> +		.idx             = parse_state->idx,
>> +	};
>> +	int ret;
>> +
>> +	*parsed = false;
>> +	ret = parse_events__scanner(str, &ps);
>> +	perf_pmu__parse_cleanup();
>> +
>> +	if (!ret) {
>> +		if (!list_empty(&ps.list)) {
>> +			*parsed = true;
>> +			list_splice(&ps.list, list);
>> +			parse_state->idx = ps.idx;
>> +		}
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>>   int __parse_events(struct evlist *evlist, const char *str,
>>   		   struct parse_events_error *err, struct perf_pmu *fake_pmu)
>>   {
>> -- 
>> 2.17.1
>>
>