perf parse-events: Add new "metric-id" term

Add a new "metric-id" term to events so that metric parsing can set an
ID that can be reliably looked up.

Metric parsing currently will turn a metric like "instructions/cycles"
into a parse events string of "{instructions,cycles}:W".

However, parse-events may change "instructions" into "instructions:u" if
perf_event_paranoid=2.

When this happens expr__resolve_id currently fails as stat-shadow adds
the ID "instructions:u" to match with the counter value and the metric
tries to look up the ID just "instructions".

A later patch will use the new term.

An example of the current problem:

  $ echo -1 > /proc/sys/kernel/perf_event_paranoid
  $ perf stat -M IPC /bin/true
   Performance counter stats for '/bin/true':

           1,217,161      inst_retired.any          #     0.97 IPC
           1,250,389      cpu_clk_unhalted.thread

         0.002064773 seconds time elapsed

         0.002378000 seconds user
         0.000000000 seconds sys

  $ echo 2 > /proc/sys/kernel/perf_event_paranoid
  $ perf stat -M IPC /bin/true
   Performance counter stats for '/bin/true':

             150,298      inst_retired.any:u        #      nan IPC
             187,095      cpu_clk_unhalted.thread:u

         0.002042731 seconds time elapsed

         0.000000000 seconds user
         0.002377000 seconds sys

Note: nan IPC is printed as an effect of "perf metric: Use NAN for
missing event IDs." but earlier versions of perf just fail with a parse
error and display no value.

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Antonov <alexander.antonov@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Kilroy <andrew.kilroy@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Changbin Du <changbin.du@intel.com>
Cc: Denys Zagorui <dzagorui@cisco.com>
Cc: Fabian Hemmer <copy@copy.sh>
Cc: Felix Fietkau <nbd@nbd.name>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jacob Keller <jacob.e.keller@intel.com>
Cc: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joakim Zhang <qiangqing.zhang@nxp.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Kees Kook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nicholas Fraser <nfraser@codeweavers.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: ShihCheng Tu <mrtoastcheng@gmail.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Wan Jiabing <wanjiabing@vivo.com>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20211015172132.1162559-15-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 1f7edfa8568a..45476a888942 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -68,6 +68,7 @@ struct evsel {
 		double			scale;
 		const char		*unit;
 		struct cgroup		*cgrp;
+		const char		*metric_id;
 		enum perf_tool_event	tool_event;
 		/* parse modifier helper */
 		int			exclude_GH;
@@ -261,6 +262,7 @@ bool evsel__match_bpf_counter_events(const char *name);
 
 int __evsel__hw_cache_type_op_res_name(u8 type, u8 op, u8 result, char *bf, size_t size);
 const char *evsel__name(struct evsel *evsel);
+const char *evsel__metric_id(const struct evsel *evsel);
 
 const char *evsel__group_name(struct evsel *evsel);
 int evsel__group_desc(struct evsel *evsel, char *buf, size_t size);