linux-kernel - Re: [PATCH v2 6/6] perf cpumap: Add range data encoding

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Message-ID: <YuZ4CEnken8U4HO5@krava>
Date:   Sun, 31 Jul 2022 14:39:36 +0200
From:   Jiri Olsa <olsajiri@...il.com>
To:     Ian Rogers <irogers@...gle.com>
Cc:     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>,
        Namhyung Kim <namhyung@...nel.org>,
        James Clark <james.clark@....com>,
        Kees Cook <keescook@...omium.org>,
        "Gustavo A. R. Silva" <gustavoars@...nel.org>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Riccardo Mancini <rickyman7@...il.com>,
        German Gomez <german.gomez@....com>,
        Colin Ian King <colin.king@...el.com>,
        Song Liu <songliubraving@...com>,
        Dave Marchevsky <davemarchevsky@...com>,
        Athira Rajeev <atrajeev@...ux.vnet.ibm.com>,
        Alexey Bayduraev <alexey.v.bayduraev@...ux.intel.com>,
        Leo Yan <leo.yan@...aro.org>, linux-perf-users@...r.kernel.org,
        linux-kernel@...r.kernel.org, Stephane Eranian <eranian@...gle.com>
Subject: Re: [PATCH v2 6/6] perf cpumap: Add range data encoding

On Tue, Jun 14, 2022 at 07:33:53AM -0700, Ian Rogers wrote:

SNIP

> +	event = cpu_map_data__alloc(&syn_data, sizeof(struct perf_event_header));
>  	if (!event)
>  		return NULL;
>  
> +	syn_data.data = &event->data;
>  	event->header.type = PERF_RECORD_CPU_MAP;
> -	event->header.size = size;
> -	event->data.type   = type;
> -
> -	cpu_map_data__synthesize(&event->data, map, type, max);
> +	event->header.size = syn_data.size;
> +	cpu_map_data__synthesize(&syn_data);
>  	return event;
>  }
>  
> +
>  int perf_event__synthesize_cpu_map(struct perf_tool *tool,
>  				   const struct perf_cpu_map *map,
>  				   perf_event__handler_t process,
> @@ -1891,24 +1894,20 @@ int perf_event__synthesize_event_update_name(struct perf_tool *tool, struct evse
>  int perf_event__synthesize_event_update_cpus(struct perf_tool *tool, struct evsel *evsel,
>  					     perf_event__handler_t process)
>  {
> -	size_t size = sizeof(struct perf_event_header) + sizeof(u64) + sizeof(u64);
> +	struct synthesize_cpu_map_data syn_data = { .map = evsel->core.own_cpus };
>  	struct perf_record_event_update *ev;
> -	int max, err;
> -	u16 type;
> -
> -	if (!evsel->core.own_cpus)
> -		return 0;

all seems fine, just looks like we no longer do this check,
might not be needed anymore, as that changed in past

thanks,
jirka

> +	int err;
>  
> -	ev = cpu_map_data__alloc(evsel->core.own_cpus, &size, &type, &max);
> +	ev = cpu_map_data__alloc(&syn_data, sizeof(struct perf_event_header) + 2 * sizeof(u64));
>  	if (!ev)
>  		return -ENOMEM;
>  
> +	syn_data.data = &ev->cpus.cpus;
>  	ev->header.type = PERF_RECORD_EVENT_UPDATE;
> -	ev->header.size = (u16)size;
> +	ev->header.size = (u16)syn_data.size;
>  	ev->type	= PERF_EVENT_UPDATE__CPUS;
>  	ev->id		= evsel->core.id[0];
> -
> -	cpu_map_data__synthesize(&ev->cpus.cpus, evsel->core.own_cpus, type, max);
> +	cpu_map_data__synthesize(&syn_data);
>  
>  	err = process(tool, (union perf_event *)ev, NULL, NULL);
>  	free(ev);
> -- 
> 2.36.1.476.g0c4daa206d-goog
>