linux-kernel - Re: [PATCH v4 04/44] perf parse-events: Don't reorder ungrouped events by pmu

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Date:   Wed, 3 May 2023 16:58:02 -0400
From:   "Liang, Kan" <kan.liang@...ux.intel.com>
To:     Ian Rogers <irogers@...gle.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Ahmad Yasin <ahmad.yasin@...el.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Stephane Eranian <eranian@...gle.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Perry Taylor <perry.taylor@...el.com>,
        Samantha Alt <samantha.alt@...el.com>,
        Caleb Biggers <caleb.biggers@...el.com>,
        Weilin Wang <weilin.wang@...el.com>,
        Edward Baker <edward.baker@...el.com>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Florian Fischer <florian.fischer@...q.space>,
        Rob Herring <robh@...nel.org>,
        Zhengjun Xing <zhengjun.xing@...ux.intel.com>,
        John Garry <john.g.garry@...cle.com>,
        Kajol Jain <kjain@...ux.ibm.com>,
        Sumanth Korikkar <sumanthk@...ux.ibm.com>,
        Thomas Richter <tmricht@...ux.ibm.com>,
        Tiezhu Yang <yangtiezhu@...ngson.cn>,
        Ravi Bangoria <ravi.bangoria@....com>,
        Leo Yan <leo.yan@...aro.org>,
        Yang Jihong <yangjihong1@...wei.com>,
        James Clark <james.clark@....com>,
        Suzuki Poulouse <suzuki.poulose@....com>,
        Kang Minchul <tegongkang@...il.com>,
        Athira Rajeev <atrajeev@...ux.vnet.ibm.com>,
        linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 04/44] perf parse-events: Don't reorder ungrouped
 events by pmu



On 2023-05-02 6:38 p.m., Ian Rogers wrote:
> The pmu_group_name by default returns "cpu" which on non-hybrid/ARM
> means that ungrouped software, and hardware events are all going to
> sort by the original insertion index. However, on hybrid and ARM
> wildcard expansion may mean the PMU name is set and events will be
> unnecessarily reordered - triggering the reordering warning.
> 
> Signed-off-by: Ian Rogers <irogers@...gle.com>

Tested-by: Kan Liang <kan.liang@...ux.intel.com>

Thanks,
Kan

> ---
>  tools/perf/util/parse-events.c | 23 +++++++++++++++--------
>  1 file changed, 15 insertions(+), 8 deletions(-)
> 
> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
> index d71019dcd614..34ba840ae19a 100644
> --- a/tools/perf/util/parse-events.c
> +++ b/tools/perf/util/parse-events.c
> @@ -2140,25 +2140,32 @@ static int evlist__cmp(void *state, const struct list_head *l, const struct list
>  	int *leader_idx = state;
>  	int lhs_leader_idx = *leader_idx, rhs_leader_idx = *leader_idx, ret;
>  	const char *lhs_pmu_name, *rhs_pmu_name;
> +	bool lhs_has_group = false, rhs_has_group = false;
>  
>  	/*
>  	 * First sort by grouping/leader. Read the leader idx only if the evsel
>  	 * is part of a group, as -1 indicates no group.
>  	 */
> -	if (lhs_core->leader != lhs_core || lhs_core->nr_members > 1)
> +	if (lhs_core->leader != lhs_core || lhs_core->nr_members > 1) {
> +		lhs_has_group = true;
>  		lhs_leader_idx = lhs_core->leader->idx;
> -	if (rhs_core->leader != rhs_core || rhs_core->nr_members > 1)
> +	}
> +	if (rhs_core->leader != rhs_core || rhs_core->nr_members > 1) {
> +		rhs_has_group = true;
>  		rhs_leader_idx = rhs_core->leader->idx;
> +	}
>  
>  	if (lhs_leader_idx != rhs_leader_idx)
>  		return lhs_leader_idx - rhs_leader_idx;
>  
> -	/* Group by PMU. Groups can't span PMUs. */
> -	lhs_pmu_name = evsel__group_pmu_name(lhs);
> -	rhs_pmu_name = evsel__group_pmu_name(rhs);
> -	ret = strcmp(lhs_pmu_name, rhs_pmu_name);
> -	if (ret)
> -		return ret;
> +	/* Group by PMU if there is a group. Groups can't span PMUs. */
> +	if (lhs_has_group && rhs_has_group) {
> +		lhs_pmu_name = evsel__group_pmu_name(lhs);
> +		rhs_pmu_name = evsel__group_pmu_name(rhs);
> +		ret = strcmp(lhs_pmu_name, rhs_pmu_name);
> +		if (ret)
> +			return ret;
> +	}
>  
>  	/* Architecture specific sorting. */
>  	return arch_evlist__cmp(lhs, rhs);