Re: [PATCH v2] perf stat: Append to default list if use -e +event

[Jin, Yao]

Hi Jiri,

On 1/21/2021 5:25 AM, Jiri Olsa wrote:
> On Mon, Jan 18, 2021 at 12:54:37PM +0800, Jin, Yao wrote:
> > Hi Jiri,
> >
> > On 1/12/2021 6:08 PM, Jiri Olsa wrote:
> > > On Mon, Jan 04, 2021 at 10:18:37AM +0800, Jin Yao wrote:
> > > > The default event list includes the most common events which are widely
> > > > used by users. But with -e option, the current perf only counts the events
> > > > assigned by -e option. Users may want to collect some extra events with
> > > > the default list. For this case, users have to manually add all the events
> > > > from the default list. It's inconvenient. Also, users may don't know how to
> > > > get the default list.
> > > >
> > > > Now it supports a simple syntax: -e +event
> > > >
> > > > The prefix '+' tells perf to append this event (or event list) to default
> > > > event list.
> > > >
> > > > Before:
> > > >
> > > > root@kbl-ppc:~# ./perf stat -e power/energy-pkg/ -a -- sleep 1
> > > >
> > > >    Performance counter stats for 'system wide':
> > > >
> > > >                 2.04 Joules power/energy-pkg/
> > > >
> > > >          1.000863884 seconds time elapsed
> > > >
> > > > After:
> > > >
> > > > root@kbl-ppc:~# ./perf stat -e +power/energy-pkg/ -a -- sleep 1
> > > >
> > > >    Performance counter stats for 'system wide':
> > > >
> > > >                 2.11 Joules +power/energy-pkg/        #    0.000 K/sec
> > >
> > > I dont think we should print the extra '+' prefix
> > >
> > > jirka
> > >
> > > >             8,007.17 msec   cpu-clock                 #    7.993 CPUs utilized
> > > >                  125        context-switches          #    0.016 K/sec
> > > >                    8        cpu-migrations            #    0.001 K/sec
> > > >                    2        page-faults               #    0.000 K/sec
> > > >            8,520,084        cycles                    #    0.001 GHz
> > > >            2,808,302        instructions              #    0.33  insn per cycle
> > > >              555,427        branches                  #    0.069 M/sec
> > > >               59,005        branch-misses             #   10.62% of all branches
> > > >
> > > >          1.001832003 seconds time elapsed
> > > >
> > > > Signed-off-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
> >
> > Printing '+' prefix is the original behavior.
> >
> > Without this patch,
> >
> > root@kbl-ppc:# ./perf stat -e +power/energy-pkg/ -a -- sleep 1
> >
> >   Performance counter stats for 'system wide':
> >
> >                2.02 Joules +power/energy-pkg/
> >
> >         1.000859434 seconds time elapsed
> >
> > The '+' prefix is printed. So I finally decide not to remove the '+' prefix
> > in order to keep original behavior.
>
> hm, originaly there's no purpose for the '+', right?
> it seems it's more like bug then anything else

Yes, I also don't understand what's the purpose for the '+'. Just a bug is possible.

> you added function to the '+' to add default events to specified event,
> which I think is good idea, but I don't think we should display the
> extra '+' in output

I'm OK to remove the extra '+' in output.

Thanks
Jin Yao

> thanks,
> jirka