linux-kernel - Re: Scrolling down broken with "perf top --hierarchy"

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Date:   Thu, 27 Oct 2016 09:45:44 +0900
From:   Taeung Song <treeze.taeung@...il.com>
To:     Namhyung Kim <namhyung@...nel.org>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Markus Trippelsdorf <markus@...ppelsdorf.de>,
        linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Jiri Olsa <jolsa@...nel.org>
Subject: Re: Scrolling down broken with "perf top --hierarchy"

Sorry for late reply, Namhyung

On 10/25/2016 01:37 AM, Namhyung Kim wrote:
> Hi Taeung,
>
> On Mon, Oct 24, 2016 at 07:10:24PM +0900, Taeung Song wrote:
>> Hi, Namhyung and Arnaldo :)
>>
>> On 10/24/2016 02:11 PM, Namhyung Kim wrote:
>>> Hi Arnaldo,
>>>
>>> Sorry for late reply.
>>>
>>> On Fri, Oct 07, 2016 at 11:35:45AM -0300, Arnaldo Carvalho de Melo wrote:
>>>> Em Fri, Oct 07, 2016 at 01:53:57PM +0900, Namhyung Kim escreveu:
>>>>> Cc-ing perf maintainers,
>>>>>
>>>>> On Fri, Oct 07, 2016 at 06:32:29AM +0200, Markus Trippelsdorf wrote:
>>>>>> On 2016.10.07 at 13:22 +0900, Namhyung Kim wrote:
>>>>>>> On Fri, Oct 07, 2016 at 05:51:18AM +0200, Markus Trippelsdorf wrote:
>>>>>>>> On 2016.10.07 at 10:17 +0900, Namhyung Kim wrote:
>>>>>>>>> On Thu, Oct 06, 2016 at 06:33:33PM +0200, Markus Trippelsdorf wrote:
>>>>>>>>>> Scrolling down is broken when using "perf top --hierarchy".
>>>>>>>>>> When it starts up everything is OK and one can scroll up and down to all
>>>>>>>>>> entries. But as further and further new entries get added to the list,
>>>>>>>>>> scrolling down is blocked (at the position of the last entry that was
>>>>>>>>>> shown directly after startup).
>>>>>>>>>
>>>>>>>>> I think below patch will fix the problem.  Please check.
>>>>>>>>
>>>>>>>> Yes. It works fine now. Many thanks.
>>>>>>>
>>>>>>> Good.  Can I add your Tested-by then?
>>>>>>
>>>>>> Sure.
>>>>>
>>>>> Ok, I'll send a formal patch with it.
>>>>>
>>>>>>
>>>>>> (And in the long run you should think of making "perf top --hierarchy"
>>>>>> the default for perf top, because it gives a much better (uncluttered)
>>>>>> overview of what is going on.)
>>>>>
>>>>> I think it's a matter of taste.  Some people prefer to see the top
>>>>> single function or something (i.e. current behavior) while others
>>>>> prefer to see a higher-level view.
>>>>>
>>>>> But we can think again about the default at least for perf-top.  I
>>>>> worried about changing default behavior because last time we did it
>>>>> for children mode many people complained about it.  But I do think the
>>>>> hierarchy mode is useful for many people though.
>>>>
>>>> So, I think in such cases we could experiment with asking the user about
>>>> switching to the new mode by showing a popup message telling what it is
>>>> about, if the user says "yes, I want to try it" switch to it and if
>>>> another hotkey is pressed later, write what was chosen (yes, switch to
>>>> this new mode, no, I don't like it, don't pester me about it anymore) to
>>>> its ~/.perfconfig file so that next time it goes straight to this new
>>>> mode, else don't ask the user again and keep using whatever mode was
>>>> there already.
>>>>
>>>> What do you think?
>>>
>>> I think it's a flexible way to set the default behavior while it seems
>>> like a little bit complicated for implementation.  Also I think it's
>>> better to popup another dialog at the end and asks for comfirmation
>>> (but it might not be appropriate for --stdio).
>>>
>>> And to do that, we need to have a (programmable) way of dealing with
>>> the configs.
>>>
>>> Taeung, is there an update on your config patchset (especially for
>>> write support)?
>>>
>>
>> Is related this link with what you said ?
>> https://lkml.org/lkml/2016/1/11/495
>
> Yep, that kind of thing.
>
>>
>> Yes, the config patchset would be need to be updated.
>> Because the config patchset which has 'write' feature
>> don't use a recent 'struct perf_config_set' so I should change it
>> to use 'perf_config_set' like show_config() of builtin-config.c:36.
>>
>> Do you need write support of perf-config command ?
>> If this feature is more necessary than a recent patchset about default
>> config array https://lkml.org/lkml/2016/9/5/17,
>> I'd remake config patchset for getting and setting features first. :)
>
> What I need is a way to add a config item with specific value.  Maybe
> I can just append a line into a config file, but it needs to check
> possible conflict somehow.  So I think it needs to process existing
> config items properly and update with the new value.
>

I got it. Understood what you said!
I'll send a patchset for this. :)

Thanks,
Taeung