Re: [PATCH v1 0/2] perf stat: Support --all-kernel and --all-user

[Jin, Yao]

On 10/10/2019 4:00 PM, Jiri Olsa wrote:
> On Thu, Oct 10, 2019 at 02:46:36PM +0800, Jin, Yao wrote:
> > On 10/1/2019 10:17 AM, Andi Kleen wrote:
> > > > > I think it's useful. Makes it easy to do kernel/user break downs.
> > > > > perf record should support the same.
> > > >
> > > > Don't we have this already with:
> > > >
> > > > [root@quaco ~]# perf stat -e cycles:u,instructions:u,cycles:k,instructions:k -a -- sleep 1
> > >
> > > This only works for simple cases. Try it for --topdown or multiple -M metrics.
> > >
> > > -Andi
> >
> > Hi Arnaldo, Jiri,
> >
> > We think it should be very useful if --all-user / --all-kernel can be
> > specified together, so that we can get a break down between user and kernel
> > easily.
> >
> > But yes, the patches for supporting this new semantics is much complicated
> > than the patch which just follows original perf-record behavior. I fully
> > understand this concern.
> >
> > So if this new semantics can be accepted, that would be very good. But if
> > you think the new semantics is too complicated, I'm also fine for posting a
> > new patch which just follows the perf-record behavior.
>
> I still need to think a bit more about this.. did you consider
> other options like cloning of the perf_evlist/perf_evsel and
> changing just the exclude* bits? might be event worse actualy ;-)

That should be another approach, but it might be a bit more complicated 
than just appending ":u"/":k" modifiers to the event name string.

> or maybe if we add modifier we could add extra events/groups
> within the parser.. like:
>
>    "{cycles,instructions}:A,{cache-misses,cache-references}:A,cycles:A"
>
> but that might be still more complicated then what you did

Yes agree.

> also please add the perf record changes so we have same code
> and logic for both if we are going to change it

If this new semantics can be accepted, I'd like to add perf record 
supporting as well. :)

Another difficulty for the new semantics is we need to create user and 
kernel stat type in runtime_stat rblist (see patch "perf stat: Support 
topdown with --all-kernel/--all-user"). That has to bring extra complexity.

Thanks
Jin Yao

> jirka