Re: [PATCH v3 12/27] perf parse-events: Support no alias assigned event inside hybrid PMU

Jin, Yao
2021-04-15T13:36:28Z

Hi Jiri,

On 4/15/2021 7:03 PM, Jiri Olsa wrote:
> On Mon, Mar 29, 2021 at 03:00:31PM +0800, Jin Yao wrote:
>
> SNIP
>
>> ---
>> v3:
>> - Rename the patch:
>> 'perf parse-events: Support hardware events inside PMU' -->
>> 'perf parse-events: Support no alias assigned event inside hybrid PMU'
>>
>> - Major code is moved to parse-events-hybrid.c.
>> - Refine the code.
>>
>> tools/perf/util/parse-events-hybrid.c | 18 +++++-
>> tools/perf/util/parse-events-hybrid.h | 3 +-
>> tools/perf/util/parse-events.c | 80 +++++++++++++++++++++++++--
>> tools/perf/util/parse-events.h | 4 +-
>> tools/perf/util/parse-events.y | 9 ++-
>> tools/perf/util/pmu.c | 4 +-
>> tools/perf/util/pmu.h | 2 +-
>> 7 files changed, 108 insertions(+), 12 deletions(-)
>
> please move the support to pass pmu_name and filter
> on it within hybrid code in to separate patch
>

OK.

>>
>> diff --git a/tools/perf/util/parse-events-hybrid.c b/tools/perf/util/parse-events-hybrid.c
>> index 8a630cbab8f3..5bf176b55573 100644
>> --- a/tools/perf/util/parse-events-hybrid.c
>> +++ b/tools/perf/util/parse-events-hybrid.c
>> @@ -64,6 +64,11 @@ static int add_hw_hybrid(struct parse_events_state *parse_state,
>> int ret;
>>
>> perf_pmu__for_each_hybrid_pmu(pmu) {
>> + if (parse_state->pmu_name &&
>> + strcmp(parse_state->pmu_name, pmu->name)) {
>> + continue;
>
> please add this check to separate function
>
> if (pmu_cmp(parse_stat))
> continue;
>

OK.

> SNIP
>
>> + if (!parse_state->fake_pmu && head_config && !found &&
>> + perf_pmu__is_hybrid(name)) {
>> + struct parse_events_term *term;
>> + int ret;
>> +
>> + list_for_each_entry(term, head_config, list) {
>> + if (!term->config)
>> + continue;
>> +
>> + ret = parse_events__with_hybrid_pmu(parse_state,
>> + term->config,
>> + name, &found,
>> + list);
>> + if (found)
>> + return ret;
>
> what if there are more terms in head_config?
> should we make sure there's just one term and fail if there's more?
>

Yes, it should have only one term in head_config.

Now I change the code to:

+ if (!parse_state->fake_pmu && head_config && !found &&
+ perf_pmu__is_hybrid(name)) {
+ struct parse_events_term *term;
+
+ term = list_first_entry(head_config, struct parse_events_term,
+ list);
+ if (term->config) {
+ return parse_events__with_hybrid_pmu(parse_state,
+ term->config,
+ name, list);
+ }
+ }

> also we already know the perf_pmu__is_hybrid(name) is true,
> so can't we just call:
>
> return parse_events__with_hybrid_pmu(....)
>
>

Yes, we can direct return parse_events__with_hybrid_pmu().

>> + }
>> + }
>>
>> if (verbose > 1) {
>> fprintf(stderr, "After aliases, add event pmu '%s' with '",
>> @@ -1605,6 +1630,15 @@ int parse_events_multi_pmu_add(struct parse_events_state *parse_state,
>> struct perf_pmu *pmu = NULL;
>> int ok = 0;
>>
>> + if (parse_state->pmu_name) {
>> + list = malloc(sizeof(struct list_head));
>> + if (!list)
>> + return -1;
>> + INIT_LIST_HEAD(list);
>> + *listp = list;
>> + return 0;
>> + }
>
> hum, why is this needed?
>

Hmm, it's not necessary in new code, sorry about that.

>> +
>> *listp = NULL;
>> /* Add it for all PMUs that support the alias */
>> list = malloc(sizeof(struct list_head));
>> @@ -2176,6 +2210,44 @@ int parse_events_terms(struct list_head *terms, const char *str)
>> return ret;
>> }
>>
>> +static int list_entries_nr(struct list_head *list)
>> +{
>> + struct list_head *pos;
>> + int n = 0;
>> +
>> + list_for_each(pos, list)
>> + n++;
>> +
>> + return n;
>> +}
>> +
>> +static int parse_events__with_hybrid_pmu(struct parse_events_state *parse_state,
>> + const char *str, char *pmu_name,
>> + bool *found, struct list_head *list)
>> +{
>> + struct parse_events_state ps = {
>> + .list = LIST_HEAD_INIT(ps.list),
>> + .stoken = PE_START_EVENTS,
>> + .pmu_name = pmu_name,
>> + .idx = parse_state->idx,
>> + };
>
> could we add this pmu_name directly to __parse_events?
>

Do you suggest we directly call __parse_events()?

int __parse_events(struct evlist *evlist, const char *str,
struct parse_events_error *err, struct perf_pmu *fake_pmu)

struct parse_events_state parse_state = {
.list = LIST_HEAD_INIT(parse_state.list),
.idx = evlist->core.nr_entries,
.error = err,
.evlist = evlist,
.stoken = PE_START_EVENTS,
.fake_pmu = fake_pmu,
};

But for parse_events__with_hybrid_pmu, we don't have valid evlist. So if we switch to
__parse_events, evlist processing may be a problem.

So could we still keep current parse_events__with_hybrid_pmu()?

> it duplicates the code plus there are some extra checks
> you don't do in here and which might be needed, like
> last->cmdline_group_boundary setup
>
>> + int ret;
>> +
>> + *found = false;
>> + ret = parse_events__scanner(str, &ps);
>> + perf_pmu__parse_cleanup();
>> +
>> + if (!ret) {
>> + if (!list_empty(&ps.list)) {
>> + *found = true;
>> + list_splice(&ps.list, list);
>> + parse_state->idx = list_entries_nr(list);
>
> could you just use ps.idx instead of list_entries_nr ?
>

Yes, the code will be changed to:

+
+ if (!ret) {
+ if (!list_empty(&ps.list)) {
+ 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)
>> {
>> diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
>> index c4f2f96304ce..f9d8e8e41c38 100644
>> --- a/tools/perf/util/parse-events.h
>> +++ b/tools/perf/util/parse-events.h
>> @@ -138,6 +138,7 @@ struct parse_events_state {
>> struct list_head *terms;
>> int stoken;
>> struct perf_pmu *fake_pmu;
>> + char *pmu_name;
>
> so it's hybrid specific, we should name it like hybrid_pmu_name or such
>

OK, I will use hybrid_pmu_name in next version.

Thanks
Jin Yao

> thanks,
> jirka
>