Re: [PATCH 2/9] perf, tools: Add support for text descriptions of events and alias add

[Namhyung Kim <namhyung@kernel.org>]

Hi Andi,

On Mon, 9 Jun 2014 18:52:45 +0200, Andi Kleen wrote:
>> Hmm.. this will print the description at right side and I think it'd be
>> better if it prints in another line(s) like below:
>
> I think it's better to show the descriptions by default without 
> an extra option. I suspect most people want to see them, or if they
> need them they won't know about obscure -v options.

I partially agree, but I guess adding -v option to the command is not
that hard for them. :)  Maybe we could add a message in order to advise
users to use -v option for description like below:

  $ perf list
  # Use -v/--verbose to see event description (if exists)
  ...

>
>> 
>>   agu_bypass_cancel.count                            [Kernel PMU event]
>>         This event counts executed load operations with all the following
>>          traits: 1. addressing of the format [base + offset], 2. the offset
>>          is between 1 and 2047, 3. the address specified in the base register
>>          is in one page and the address [base+offset] is in an
>
> The problem with this format is that it is not compatible, so it would
> break existing parsers that look at perf list output.  That is why I ended up
> with the right side format.

Hmm.. I think existing parsers should not use -v option then.  The perf
list was for listing only event names (and their types).

I think the main problem of the right side format is that it hurts
readability especially on small screens/terminals.

Thanks,
Namhyung

>
>
>>   arith.fpu_div                                      [Kernel PMU event]
>>         Divide operations executed
>>   arith.fpu_div_active                               [Kernel PMU event]
>>         Cycles when divider is busy executing divide operations
>>   ...
>> 
>> 
>> I just tweaked it using -v option for perf list.  Below is the change I
>> made on top of your series.  What do you think?
>
> I prefer not to apply that patch.
>
> I guess what could make sense is a quiet option to not print
> descriptions.
>
> -Andi