Re: [PATCH] perf list: Hide deprecated events by default

From: Jiri Olsa <jolsa@redhat.com>
To: "Jin, Yao" <yao.jin@linux.intel.com>
Cc: acme@kernel.org, jolsa@kernel.org, peterz@infradead.org,
	mingo@redhat.com, alexander.shishkin@linux.intel.com,
	Linux-kernel@vger.kernel.org, ak@linux.intel.com,
	kan.liang@intel.com, yao.jin@intel.com
Subject: Re: [PATCH] perf list: Hide deprecated events by default
Date: Wed, 16 Oct 2019 12:27:42 +0200	[thread overview]
Message-ID: <20191016102742.GA30251@krava> (raw)
In-Reply-To: <2a1d1883-ca28-2dae-4ae3-fbae81174d55@linux.intel.com>

On Wed, Oct 16, 2019 at 06:22:06PM +0800, Jin, Yao wrote:
> 
> 
> On 10/16/2019 3:27 PM, Jiri Olsa wrote:
> > On Wed, Oct 16, 2019 at 08:59:13AM +0800, Jin, Yao wrote:
> > > 
> > > 
> > > On 10/15/2019 5:14 PM, Jiri Olsa wrote:
> > > > On Tue, Oct 15, 2019 at 10:53:57AM +0800, Jin Yao wrote:
> > > > > There are some deprecated events listed by perf list. But we can't remove
> > > > > them from perf list with ease because some old scripts may use them.
> > > > > 
> > > > > Deprecated events are old names of renamed events.  When an event gets
> > > > > renamed the old name is kept around for some time and marked with
> > > > > Deprecated. The newer Intel event lists in the tree already have these
> > > > > headers.
> > > > > 
> > > > > So we need to keep them in the event list, but provide a new option to
> > > > > show them. The new option is "--deprecated".
> > > > > 
> > > > > With this patch, the deprecated events are hidden by default but they can
> > > > > be displayed when option "--deprecated" is enabled.
> > > > 
> > > > not sure it's wise to hide them, because people will not read man page
> > > > to find --deprecated option, they will rather complain right away ;-)
> > > > 
> > > > how about to display them as another topic, like:
> > > > 
> > > > pipeline:
> > > > 	...
> > > > uncore:
> > > > 	...
> > > > deprecated:
> > > > 	...
> > > > 
> > > > jirka
> > > > 
> > > 
> > > Hi Jiri,
> > > 
> > > I don't know if we add a new topic "deprecated" in perf list output, does
> > > the old script need to be modified as well?
> > > 
> > > Say the events are moved to the "deprecated" section, I just guess the
> > > script needs the modification.
> > > 
> > > That's just my personal guess. :)
> > 
> > i did not mean adding new topic all the way down,
> > just to display the deprecated events like that
> > 
> > jirka
> > 
> 
> Sorry, maybe I misunderstood what you suggested. Correct me if my
> understanding is wrong.
> 
> Now the perf list output is like:
> 
> pipeline:
>   event1
>   event2
> uncore:
>   event3
>   event4
> 
> My understanding for your suggestion is, we need to add "deprecated", for
> example:
> 
> pipeline:
>   event1
>   event2
> uncore:
>   event4
> deprecated:
>   event3
> 
> In above example, I assume the event3 is deprecated.
> 
> So my worry is, the user's old script may not find the event3 if we move it
> from "uncore" to "deprecated". Maybe I'm worried a lot. :(

well, your patch removes it unless you specify --deprecated
option of course

perhaps we could do

deprecated:
uncore:
  event3

jirka