linux-kernel - Re: [PATCH] perf top: Use evsel's cpus to replace user_requested

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Date: Mon, 18 Dec 2023 16:07:37 -0500
From: "Liang, Kan" <kan.liang@...ux.intel.com>
To: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Mark Rutland <mark.rutland@....com>, Ian Rogers <irogers@...gle.com>,
 Namhyung Kim <namhyung@...nel.org>, maz@...nel.org, marcan@...can.st,
 linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org
Subject: Re: [PATCH] perf top: Use evsel's cpus to replace user_requested_cpus



On 2023-12-18 3:23 p.m., Arnaldo Carvalho de Melo wrote:
> Em Fri, Dec 15, 2023 at 01:53:12PM -0500, Liang, Kan escreveu:
>> On 2023-12-15 1:26 p.m., Arnaldo Carvalho de Melo wrote:
>>> Right, I implemented it in a slightly different way, but end result
>>> should be the same:
> 
>>> From: Arnaldo Carvalho de Melo <acme@...hat.com>
>>> Date: Fri, 15 Dec 2023 15:23:30 -0300
>>> Subject: [PATCH 1/1] perf evlist: Move event attributes to after the / when uniquefying using the PMU name
>  
>> Looks good to me and verified.
> 
>> Tested-by: Kan Liang <kan.liang@...ux.intel.com>
> 
> I ended up with a bit more simplified version:
> 
> From 22ecc4601e28a12661f14ca877e39348dab6be8e Mon Sep 17 00:00:00 2001
> From: Arnaldo Carvalho de Melo <acme@...hat.com>
> Date: Fri, 15 Dec 2023 15:23:30 -0300
> Subject: [PATCH 1/1] perf evlist: Move event attributes to after the / when
>  uniquefying using the PMU name
> 
> When turning an event with attributes to the format including the PMU we
> need to move the "event:attributes" format to "event/attributes/" so
> that we can copy the event displayed and use it in the command line,
> i.e. in 'perf top' we had:
> 
>  1K cpu_atom/cycles:P/
>  11K cpu_core/cycles:P/
> 
> If I try to use that on the command line:
> 
>   # perf top -e cpu_atom/cycles:P/
>   event syntax error: 'cpu_atom/cycles:P/'
>                                 \___ Bad event or PMU
> 
>   Unable to find PMU or event on a PMU of 'cpu_atom'
> 
>   Initial error:
>   event syntax error: 'cpu_atom/cycles:P/'
>                                 \___ unknown term 'cycles:P' for pmu
>   'cpu_atom'
> 
>   valid terms:
> 
>     event,pc,edge,offcore_rsp,ldlat,inv,umask,cmask,config,config1,config2,config3,name,period,freq,branch_type,time,call-graph,stack-size,no-inherit,inherit,max-stack,nr,no-overwrite,overwrite ,driver-config,percore,aux-output,aux-sample-size,metric-id,raw,legacy-cache,hardware
>   Run
>     'perf list' for a list of valid events
> 
>   Usage: perf top [<options>]
> 
>      -e, --event <event>   event selector. use 'perf list' to list available events
>   #
> 
> Cc: Hector Martin <marcan@...can.st>
> Cc: Ian Rogers <irogers@...gle.com>
> Cc: Kan Liang <kan.liang@...ux.intel.com>
> Cc: Marc Zyngier <maz@...nel.org>
> Cc: Mark Rutland <mark.rutland@....com>
> Cc: Namhyung Kim <namhyung@...nel.org>
> Link: https://lore.kernel.org/lkml/ZXxyanyZgWBTOnoK@kernel.org
> Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>

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

Thanks,
Kan
> ---
>  tools/perf/util/evlist.c | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index 6f0892803c2249af..95f25e9fb994ab2a 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -2521,9 +2521,8 @@ void evlist__warn_user_requested_cpus(struct evlist *evlist, const char *cpu_lis
>  
>  void evlist__uniquify_name(struct evlist *evlist)
>  {
> +	char *new_name, empty_attributes[2] = ":", *attributes;
>  	struct evsel *pos;
> -	char *new_name;
> -	int ret;
>  
>  	if (perf_pmus__num_core_pmus() == 1)
>  		return;
> @@ -2535,11 +2534,17 @@ void evlist__uniquify_name(struct evlist *evlist)
>  		if (strchr(pos->name, '/'))
>  			continue;
>  
> -		ret = asprintf(&new_name, "%s/%s/",
> -			       pos->pmu_name, pos->name);
> -		if (ret) {
> +		attributes = strchr(pos->name, ':');
> +		if (attributes)
> +			*attributes = '\0';
> +		else
> +			attributes = empty_attributes;
> +
> +		if (asprintf(&new_name, "%s/%s/%s", pos->pmu_name, pos->name, attributes + 1)) {
>  			free(pos->name);
>  			pos->name = new_name;
> +		} else {
> +			*attributes = ':';
>  		}
>  	}
>  }