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

[Jin, Yao]

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. :(

Thanks
Jin Yao