linux-kernel - Re: [PATCH v2 16/27] perf evlist: Warn as events from different hybrid PMUs in a group

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Date:   Tue, 16 Mar 2021 00:03:52 +0100
From:   Jiri Olsa <jolsa@...hat.com>
To:     Jin Yao <yao.jin@...ux.intel.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 v2 16/27] perf evlist: Warn as events from different
 hybrid PMUs in a group

On Thu, Mar 11, 2021 at 03:07:31PM +0800, Jin Yao wrote:

SNIP

>  				goto try_again;
>  			}
> +
> +			if (errno == EINVAL && perf_pmu__hybrid_exist())
> +				evlist__warn_hybrid_group(evlist);
>  			rc = -errno;
>  			evsel__open_strerror(pos, &opts->target, errno, msg, sizeof(msg));
>  			ui__error("%s\n", msg);
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index 7a732508b2b4..6f780a039db0 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -239,6 +239,9 @@ static void evlist__check_cpu_maps(struct evlist *evlist)
>  	struct evsel *evsel, *pos, *leader;
>  	char buf[1024];
>  
> +	if (evlist__hybrid_exist(evlist))
> +		return;

this should be in separate patch and explained

> +
>  	evlist__for_each_entry(evlist, evsel) {
>  		leader = evsel->leader;
>  
> @@ -726,6 +729,10 @@ enum counter_recovery {
>  static enum counter_recovery stat_handle_error(struct evsel *counter)
>  {
>  	char msg[BUFSIZ];
> +
> +	if (perf_pmu__hybrid_exist() && errno == EINVAL)
> +		evlist__warn_hybrid_group(evsel_list);
> +
>  	/*
>  	 * PPC returns ENXIO for HW counters until 2.6.37
>  	 * (behavior changed with commit b0a873e).
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index f139151b9433..5ec891418cdd 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -2224,3 +2224,47 @@ void evlist__invalidate_all_cpus(struct evlist *evlist)
>  	perf_cpu_map__put(evlist->core.all_cpus);
>  	evlist->core.all_cpus = perf_cpu_map__empty_new(1);
>  }
> +
> +static bool group_hybrid_conflict(struct evsel *leader)
> +{
> +	struct evsel *pos, *prev = NULL;
> +
> +	for_each_group_evsel(pos, leader) {
> +		if (!pos->pmu_name || !perf_pmu__is_hybrid(pos->pmu_name))
> +			continue;
> +
> +		if (prev && strcmp(prev->pmu_name, pos->pmu_name))
> +			return true;
> +
> +		prev = pos;
> +	}
> +
> +	return false;
> +}
> +
> +void evlist__warn_hybrid_group(struct evlist *evlist)
> +{
> +	struct evsel *evsel;
> +
> +	evlist__for_each_entry(evlist, evsel) {
> +		if (evsel__is_group_leader(evsel) &&
> +		    evsel->core.nr_members > 1 &&

hm, could we just iterate all the members and make sure the first found
hybrid event's pmu matches the pmu of the rest hybrid events in the list?

> +		    group_hybrid_conflict(evsel)) {
> +			WARN_ONCE(1, "WARNING: Group has events from "
> +				     "different hybrid PMUs\n");
> +			return;
> +		}
> +	}
> +}
> +
> +bool evlist__hybrid_exist(struct evlist *evlist)

evlist__has_hybrid seems better


jirka