linux-kernel - Re: [PATCH V2] perf tools: adding support for address filters

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Message-ID: <20160831065731.GA31764@krava>
Date:   Wed, 31 Aug 2016 08:57:31 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     Mathieu Poirier <mathieu.poirier@...aro.org>
Cc:     acme@...nel.org, mingo@...hat.com, peterz@...radead.org,
        alexander.shishkin@...ux.intel.com, jolsa@...nel.org,
        acme@...radead.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH V2] perf tools: adding support for address filters

On Tue, Aug 30, 2016 at 10:10:15AM -0600, Mathieu Poirier wrote:
> This patch makes it possible to use the current filter
> framework with address filters.  That way address filters for
> HW tracers such as CoreSight and IntelPT can be communicated
> to the kernel drivers.
> 
> CC: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
> Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
> 
> ---
> Changes for V2:
>  - Rebased to v4.8-rc4.
>  - Revisited error path.
> ---
> 
>  tools/perf/util/parse-events.c | 30 +++++++++++++++++++++++++-----
>  1 file changed, 25 insertions(+), 5 deletions(-)
> 
> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
> index 2eb8b1ed4cc8..1df413fbf7f8 100644
> --- a/tools/perf/util/parse-events.c
> +++ b/tools/perf/util/parse-events.c
> @@ -1760,12 +1760,26 @@ foreach_evsel_in_last_glob(struct perf_evlist *evlist,
>  static int set_filter(struct perf_evsel *evsel, const void *arg)
>  {
>  	const char *str = arg;
> +	bool found = false;
> +	int nr_addr_filters = 0;
> +	struct perf_pmu *pmu = NULL;
>  
> -	if (evsel == NULL || evsel->attr.type != PERF_TYPE_TRACEPOINT) {
> -		fprintf(stderr,
> -			"--filter option should follow a -e tracepoint option\n");
> -		return -1;
> -	}
> +	if (evsel == NULL)
> +		goto err;
> +
> +	while ((pmu = perf_pmu__scan(pmu)) != NULL)
> +		if (pmu->type == evsel->attr.type) {
> +			found = true;
> +			break;
> +		}
> +
> +	if (found)
> +		perf_pmu__scan_file(pmu, "nr_addr_filters",
> +				    "%d", &nr_addr_filters);
> +
> +
> +	if (evsel->attr.type != PERF_TYPE_TRACEPOINT && !nr_addr_filters)
> +		goto err;

should we display another error message for !nr_addr_filters case?
the one below is misleading in this case

jirka

>  
>  	if (perf_evsel__append_filter(evsel, "&&", str) < 0) {
>  		fprintf(stderr,
> @@ -1774,6 +1788,12 @@ static int set_filter(struct perf_evsel *evsel, const void *arg)
>  	}
>  
>  	return 0;
> +
> +err:
> +	fprintf(stderr,
> +		"--filter option should follow a -e tracepoint or HW tracer option\n");
> +
> +	return -1;
>  }
>  
>  int parse_filter(const struct option *opt, const char *str,
> -- 
> 2.7.4
>