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Date: Sat, 18 Apr 2015 19:39:27 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
        lkml <linux-kernel@vger.kernel.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Paul Mackerras <paulus@samba.org>, David Ahern <dsahern@gmail.com>,
        Namhyung Kim <namhyung@kernel.org>
Subject: Re: [RFC 0/6] perf tools: Report event parsing errors
Message-ID: <20150418173927.GA5897@gmail.com>
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* Jiri Olsa <jolsa@kernel.org> wrote:

> hi,
> adding support to report error from event string parsing.

Very nice!

> This patchset contains support for standard parsing errors and more 
> logic to recognize tracepoint and 'pmu//' terms, like:
> 
>   $ perf record -e 'sched:krava' ls
>   invalid or unsupported event: 'sched:krava'
>                                  \___ unknown tracepoint
> 
>   $ ./perf record -e 'cpu/even=0x1/' ls
>   invalid or unsupported event: 'cpu/even=0x1/'
>                                      \___ unknown term
> 
>   $ perf record -e cycles,cache-mises ls
>   invalid or unsupported event: '..es,cache-mises'
>                                            \___ parser error
> 
> any feedback about the error string shape would be great ;-)

So since we now know exactly what's going on, we might want to drop 
the 'invalid or unsupported event' language as well, and make it 
specific:

   $ ./perf record -e 'cpu/even=0x1/' ls
   event syntax error: 'cpu/even=0x1/'
                            \___ unknown term
 

?

Also, for the above error, could we easily list the valid terms? An 
error like:

   $ ./perf record -e 'cpu/even=0x1/' ls
   event syntax error: 'cpu/even=0x1/'
                            \___ unknown term
   valid terms: "event", "raw".

or so?

Thanks,

	Ingo