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

From: Namhyung Kim
Date: Tue Jun 10 2014 - 01:58:55 EST


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
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