Re: [PATCH v9 4/4] perf tools: add support for libpfm4

[Ian Rogers <irogers@google.com>]

On Thu, Apr 16, 2020 at 1:10 PM Jiri Olsa <jolsa@redhat.com> wrote:
>
> On Thu, Apr 16, 2020 at 09:02:54AM -0700, Ian Rogers wrote:
> > On Thu, Apr 16, 2020 at 2:55 AM Jiri Olsa <jolsa@redhat.com> wrote:
> > >
> > > On Wed, Apr 15, 2020 at 11:35:51PM -0700, Ian Rogers wrote:
> > > > From: Stephane Eranian <eranian@google.com>
> > > >
> > > > This patch links perf with the libpfm4 library if it is available
> > > > and NO_LIBPFM4 isn't passed to the build. The libpfm4 library
> > > > contains hardware event tables for all processors supported by
> > > > perf_events. It is a helper library that helps convert from a
> > > > symbolic event name to the event encoding required by the
> > > > underlying kernel interface. This library is open-source and
> > > > available from: http://perfmon2.sf.net.
> > > >
> > > > With this patch, it is possible to specify full hardware events
> > > > by name. Hardware filters are also supported. Events must be
> > > > specified via the --pfm-events and not -e option. Both options
> > > > are active at the same time and it is possible to mix and match:
> > > >
> > > > $ perf stat --pfm-events inst_retired:any_p:c=1:i -e cycles ....
> > > >
> > > > Signed-off-by: Stephane Eranian <eranian@google.com>
> > > > Reviewed-by: Ian Rogers <irogers@google.com>
> > >
> > >         # perf list
> > >         ...
> > >         perf_raw pfm-events
> > >           r0000
> > >             [perf_events raw event syntax: r[0-9a-fA-F]+]
> > >
> > >         skl pfm-events
> > >           UNHALTED_CORE_CYCLES
> > >             [Count core clock cycles whenever the clock signal on the specific core is running (not halted)]
> > >           UNHALTED_REFERENCE_CYCLES
> > >
> > > please add ':' behind the '* pfm-events' label
> >
> > Thanks! Not sure I follow here. skl here is the pmu. pfm-events is
> > here just to make it clearer these are --pfm-events. The event is
> > selected with '--pfm-events UNHALTED_CORE_CYCLES'. Will putting
> > skl:pfm-events here make it look like that is part of the event
> > encoding?
>
> aah I might have misunderstood the output here then, we have preceeding
> output like:
>
> cache:
>   l1d.replacement
>        [L1D data line replacements]
>
> so I thought the 'skl pfm-events' is just a label
>
>
> how about we use the first current label in the middle like:
>
>         # perf list
>         List of pre-defined events (to be used in -e):
>
>           current events stuff
>
>         List of pfm events (to be used in --pfm-xxx):
>
>           pfm events stuff
>
> or maybe put it under 'perf list --pfm', thoughts?

We decided on the former which is in the new patch set. However, the
output isn't conditional on the pager being used, which it is in the
regular event case.
https://lore.kernel.org/lkml/20200416221457.46710-1-irogers@google.com/T/#t

Let me know if there is more to address. Thanks!
Ian

> jirka
>