Re: [PATCH] perf parser: Improve error message for PMU address filters

Jiri Olsa
2018-07-04T10:24:33Z

On Wed, Jul 04, 2018 at 11:54:09AM +0200, Jack Henschel wrote:
> This patch improves the error message of the perf events parser
> when the PMU hardware does not support address filters.
>
> Previously, the perf returned the following error:
> > --filter option should follow a -e tracepoint or HW tracer option
> This implies there is some syntax error present in the command line,
> which is not true. Rather, notify the user that the CPU does not have
> support for this feature.
>
> For example, Intel chips based on the Broadwell micro-archticture have
> the Intel PT PMU, but do not support address filtering.

looks ok, but please provide real examples of those error outputs in changelog

thanks,
jirka

>
> Signed-off-by: Jack Henschel <jackdev@mailbox.org>
> ---
> tools/perf/util/parse-events.c | 20 ++++++++++----------
> 1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
> index 15eec49e71a1..f8cd3e7c9186 100644
> --- a/tools/perf/util/parse-events.c
> +++ b/tools/perf/util/parse-events.c
> @@ -1991,8 +1991,11 @@ static int set_filter(struct perf_evsel *evsel, const void *arg)
> int nr_addr_filters = 0;
> struct perf_pmu *pmu = NULL;
>
> - if (evsel == NULL)
> - goto err;
> + if (evsel == NULL) {
> + fprintf(stderr,
> + "--filter option should follow a -e tracepoint or HW tracer option\n");
> + return -1;
> + }
>
> if (evsel->attr.type == PERF_TYPE_TRACEPOINT) {
> if (perf_evsel__append_tp_filter(evsel, str) < 0) {
> @@ -2014,8 +2017,11 @@ static int set_filter(struct perf_evsel *evsel, const void *arg)
> perf_pmu__scan_file(pmu, "nr_addr_filters",
> "%d", &nr_addr_filters);
>
> - if (!nr_addr_filters)
> - goto err;
> + if (!nr_addr_filters) {
> + fprintf(stderr,
> + "This CPU does not support address filtering\n");
> + return -1;
> + }
>
> if (perf_evsel__append_addr_filter(evsel, str) < 0) {
> fprintf(stderr,
> @@ -2024,12 +2030,6 @@ 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,
> --
> 2.18.0
>