Re: [PATCH 00/18] perf metric: Add support to reuse metric

[Jiri Olsa <jolsa@redhat.com>]

On Thu, Jul 16, 2020 at 08:50:56AM +0100, John Garry wrote:
> On 12/07/2020 14:26, Jiri Olsa wrote:
> > hi,
> > this patchset is adding the support to reused metric in another
> > metric. The metric needs to be referenced by 'metric:' prefix.
> > 
> > For example, to define IPC by using CPI with change like:
> > 
> >           "BriefDescription": "Instructions Per Cycle (per Logical Processor)",
> >   -       "MetricExpr": "INST_RETIRED.ANY / CPU_CLK_UNHALTED.THREAD",
> >   +       "MetricExpr": "1/metric:CPI",
> >           "MetricGroup": "TopDownL1",
> >           "MetricName": "IPC"
> > 
> > I won't be able to find all the possible places we could
> > use this at, so I wonder you guys (who was asking for this)
> > would try it and come up with comments if there's something
> > missing or we could already use it at some places.
> > 
> > It's based on Arnaldo's tmp.perf/core.
> > 
> > v2 changes:
> >    - collected Ian's acks for few patches [Ian]
> >    - renamed expr__add_id to expr__add_id_val [Ian]
> >    - renamed expr_parse_data to expr_id_data [Ian]
> >    - added recursion check [Ian]
> >    - added metric test for DCache_L2 metric [Ian]
> >    - added some renames as discussed in review [Ian]
> > 
> > Also available in here:
> >    git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
> >    perf/metric
> > 
> > thanks,
> > jirka
> > 
> > 
> > ---
> > Jiri Olsa (18):
> >        perf metric: Rename expr__add_id to expr__add_val
> >        perf metric: Add struct expr_id_data to keep expr value
> >        perf metric: Add expr__add_id function
> >        perf metric: Change expr__get_id to return struct expr_id_data
> >        perf metric: Add expr__del_id function
> >        perf metric: Add find_metric function
> >        perf metric: Add add_metric function
> >        perf metric: Rename __metricgroup__add_metric to __add_metric
> >        perf metric: Collect referenced metrics in struct metric_ref_node
> >        perf metric: Collect referenced metrics in struct metric_expr
> >        perf metric: Add referenced metrics to hash data
> >        perf metric: Compute referenced metrics
> >        perf metric: Add events for the current group
> >        perf metric: Add cache_miss_cycles to metric parse test
> >        perf metric: Add DCache_L2 to metric parse test
> >        perf metric: Add recursion check when processing nested metrics
> >        perf metric: Rename struct egroup to metric
> >        perf metric: Rename group_list to list
> 
> I was thinking that a test metric using this reuse feature could be added in
> pmu-events/arch/test/test_cpu. But since no relevant parsing is done in
> jevents, maybe not a lot of value. Just for a bit more completeness.

ok, I think it's a good idea

thanks,
jirka