linux-kernel - Re: [PATCH] perf parse-events: Move slots only with topdown

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 22 Mar 2022 07:48:48 -0400
From:   "Liang, Kan" <kan.liang@...ux.intel.com>
To:     Ian Rogers <irogers@...gle.com>,
        Zhengjun Xing <zhengjun.xing@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        Andi Kleen <ak@...ux.intel.com>,
        James Clark <james.clark@....com>,
        John Garry <john.garry@...wei.com>,
        linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org
Cc:     Stephane Eranian <eranian@...gle.com>
Subject: Re: [PATCH] perf parse-events: Move slots only with topdown



On 3/21/2022 6:33 PM, Ian Rogers wrote:
> If slots isn't with a topdown event then moving it is unnecessary. For
> example {instructions, slots} is re-ordered:
> 
> $ perf stat -e '{instructions,slots}' -a sleep 1
> 
>   Performance counter stats for 'system wide':
> 
>         936,600,825      slots
>         144,440,968      instructions
> 
>         1.006061423 seconds time elapsed
> 
> Which can break tools expecting the command line order to match the
> printed order. It is necessary to move the slots event first when it
> appears with topdown events. Add extra checking so that the slots event
> is only moved in the case of there being a topdown event like:
> 
> $ perf stat -e '{instructions,slots,topdown-fe-bound}' -a sleep 1
> 
>   Performance counter stats for 'system wide':
> 
>          2427568570      slots
>           300927614      instructions
>           551021649      topdown-fe-bound
> 
>         1.001771803 seconds time elapsed
> 
> Fixes: 94dbfd6781a0 ("perf parse-events: Architecture specific leader override")
> Reported-by: Kan Liang <kan.liang@...ux.intel.com>
> Signed-off-by: Ian Rogers <irogers@...gle.com>

Thanks Ian. The patch works well.

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

Thanks,
Kan
> ---
>   tools/perf/arch/x86/util/evlist.c | 18 ++++++++++++++----
>   1 file changed, 14 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/perf/arch/x86/util/evlist.c b/tools/perf/arch/x86/util/evlist.c
> index 8d9b55959256..cfc208d71f00 100644
> --- a/tools/perf/arch/x86/util/evlist.c
> +++ b/tools/perf/arch/x86/util/evlist.c
> @@ -20,17 +20,27 @@ int arch_evlist__add_default_attrs(struct evlist *evlist)
>   
>   struct evsel *arch_evlist__leader(struct list_head *list)
>   {
> -	struct evsel *evsel, *first;
> +	struct evsel *evsel, *first, *slots = NULL;
> +	bool has_topdown = false;
>   
>   	first = list_first_entry(list, struct evsel, core.node);
>   
>   	if (!pmu_have_event("cpu", "slots"))
>   		return first;
>   
> +	/* If there is a slots event and a topdown event then the slots event comes first. */
>   	__evlist__for_each_entry(list, evsel) {
> -		if (evsel->pmu_name && !strcmp(evsel->pmu_name, "cpu") &&
> -			evsel->name && strcasestr(evsel->name, "slots"))
> -			return evsel;
> +		if (evsel->pmu_name && !strcmp(evsel->pmu_name, "cpu") && evsel->name) {
> +			if (strcasestr(evsel->name, "slots")) {
> +				slots = evsel;
> +				if (slots == first)
> +					return first;
> +			}
> +			if (!strncasecmp(evsel->name, "topdown", 7))
> +				has_topdown = true;
> +			if (slots && has_topdown)
> +				return slots;
> +		}
>   	}
>   	return first;
>   }