Re: [PATCH v2 14/19] perf, tools, stat: Support JSON metrics in perf stat

Andi Kleen
2017-08-28T16:47:00Z

On Mon, Aug 28, 2017 at 11:19:21AM +0200, Jiri Olsa wrote:
> On Fri, Aug 11, 2017 at 04:26:29PM -0700, Andi Kleen wrote:
> > From: Andi Kleen <ak@linux.intel.com>
> >
> > Add generic support for standalone metrics specified in JSON files
> > to perf stat. A metric is a formula that uses multiple events
> > to compute a higher level result (e.g. IPC).
> >
> > Previously metrics were always tied to an event and automatically
> > enabled with that event. But now change it that we can have
> > standalone metrics. They are in the same JSON data structure
> > as events, but don't have an event name.
> >
> > We also allow to organize the metrics in metric groups, which
> > allows a short cut to select several related metrics at once.
> >
> > Add a new -M / --metrics option to perf stat that adds the metrics
> > or metric groups specified.
> >
> > Add the core code to manage and parse the metric groups. They
> > are collected from the JSON data structures into a separate rblist.
> > When computing shadow values look for metrics in that list.
> > Then they are computed using the existing saved values infrastructure
> > in stat-shadow.c
> >
> > The actual JSON metrics are in a separate pull request.
>
> would need this for testing.. could you please put it somewhere?

It was in the 0/0 (which I forgot to post for the second rev)

---

Support standalone metrics and metric groups for perf v2

Add generic support for standalone metrics specified in JSON files
to perf stat. A metric is a formula that uses multiple events
to compute a higher level result (e.g. IPC).

For more complex metrics we need to have micro architecture
specific knowledge, so it makes sense to tie metrics to
JSON event lists.

Previously metrics were always tied to an event and automatically
enabled with that event. But now change it that we can have
standalone metrics. They are in the same JSON data structure
as events, but don't have an event name, only a metric name.

We also allow to organize the metrics in metric groups, which
allows a short cut to select several related metrics at once.

This patch kit adds the code to perf to manage metric groups

The first few patches are generic bug fixes and can be applied
directly. Then there is a 'weak group' feature that is useful
independently from metrics. After there are metrics specific
patches.

The patches are available in

git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-misc.git perf/metric-group-5

The actual Intel JSON metrics are available in git as a separate pull
request in

git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-misc.git perf/intel-json-metrics-2

Some example output:
% perf list metricgroup
..
Metric Groups:

DSB:
DSB_Coverage
[Fraction of Uops delivered by the DSB (aka Decoded Icache; or Uop Cache)]
FLOPS:
GFLOPs
[Giga Floating Point Operations Per Second]
Frontend:
IFetch_Line_Utilization
[Rough Estimation of fraction of fetched lines bytes that were likely consumed by program instructions]
Frontend_Bandwidth:
DSB_Coverage
[Fraction of Uops delivered by the DSB (aka Decoded Icache; or Uop Cache)]
Memory_BW:
MLP
[Memory-Level-Parallelism (average number of L1 miss demand load when there is at least 1 such miss)]

% perf stat -M Summary --metric-only -a sleep 1

Performance counter stats for 'system wide':

Instructions CLKS CPU_Utilization GFLOPs SMT_2T_Utilization Kernel_Utilization
317614222.0 1392930775.0 0.0 0.0 0.2 0.1

1.001497549 seconds time elapsed

% perf stat -M GFLOPs flops

Performance counter stats for 'flops':

3,999,541,471 fp_comp_ops_exe.sse_scalar_single # 1.2 GFLOPs (66.65%)
14 fp_comp_ops_exe.sse_scalar_double (66.65%)
0 fp_comp_ops_exe.sse_packed_double (66.67%)
0 fp_comp_ops_exe.sse_packed_single (66.70%)
0 simd_fp_256.packed_double (66.70%)
0 simd_fp_256.packed_single (66.67%)

3.238372845 seconds time elapsed