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SubjectRe: [PATCH 1/4] perf trace: Improve error message when receive non-tracepoint events
Em Fri, Apr 08, 2016 at 03:07:22PM +0000, Wang Nan escreveu:
> Before this patch, strange error message is provided if passed a
> non-tracepoint event to 'perf trace':
>
> # perf trace -a --ev cycles sleep 1
> Failed to set filter "common_pid != 27500" on event cycles with 22 (Invalid argument)
>
> This is because 'perf trace' accepts all valid events during cmdline
> parsing, but in fact user can only provide tracepoints, because it
> needs filter.
>
> This patch validate evlist, report error earlier:
>
> # ./perf trace -a --ev cycles sleep 1
> Only support tracepoint events!

Humm, perhaps we should instead refrain from setting filters to non
tracepoint events? I.e. I don't see why we whouldn't support, say,
software events...

/me trying some now, i.e.:

# trace --ev minor-faults --no-syscalls

But it has some issues...

- Arnaldo

> Signed-off-by: Wang Nan <wangnan0@huawei.com>
> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Li Zefan <lizefan@huawei.com>
> Cc: pi3orama@163.com
> ---
> tools/perf/builtin-trace.c | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
> diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
> index 11290b5..6fbed86 100644
> --- a/tools/perf/builtin-trace.c
> +++ b/tools/perf/builtin-trace.c
> @@ -2680,6 +2680,17 @@ out_enomem:
> goto out;
> }
>
> +static int validate_evlist(struct perf_evlist *evlist)
> +{
> + struct perf_evsel *evsel;
> +
> + evlist__for_each(evlist, evsel) {
> + if (evsel->attr.type != PERF_TYPE_TRACEPOINT)
> + return -EINVAL;
> + }
> + return 0;
> +}
> +
> static int trace__run(struct trace *trace, int argc, const char **argv)
> {
> struct perf_evlist *evlist = trace->evlist;
> @@ -3273,6 +3284,11 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
> argc = parse_options_subcommand(argc, argv, trace_options, trace_subcommands,
> trace_usage, PARSE_OPT_STOP_AT_NON_OPTION);
>
> + if (validate_evlist(trace.evlist)) {
> + pr_err("Only support tracepoint events!\n");
> + return -EINVAL;
> + }
> +
> if (trace.trace_pgfaults) {
> trace.opts.sample_address = true;
> trace.opts.sample_time = true;
> --
> 1.8.3.4

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