perf metric: Encode and use metric-id as qualifier

For a metric like IPC a group of events like {instructions,cycles}:W
would be formed.

If the events names were changed in parsing then the metric expression
parser would fail to find them.

This change makes the event encoding be something like:

  {instructions/metric-id=instructions/, cycles/metric-id=cycles/}

and then uses the evsel's stable metric-id value to locate the events.

This fixes the case that an event is restricted to user because of the
paranoia setting:

  $ 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        #      0.77 IPC
             187,095      cpu_clk_unhalted.thread:u

         0.002042731 seconds time elapsed

         0.000000000 seconds user
         0.002377000 seconds sys

Adding the metric-id as a qualifier has a complication in that
qualifiers will become embedded in qualifiers.

For example, msr/tsc/ could become msr/tsc,metric-id=msr/tsc// which
will fail parse-events.

To solve this problem the metric is encoded and decoded for the
metric-id with !<num> standing in for an encoded value.

Previously ! wasn't parsed.

With this msr/tsc/ becomes msr/tsc,metric-id=msr!3tsc!3/

The metric expression parser is changed so that @ isn't changed to /,
instead this is done when the ID is encoded for parse events.

metricgroup__add_metric_non_group() and metricgroup__add_metric_weak_group()
need to inject the metric-id qualifier, so to avoid repetition they are
merged into a single metricgroup__build_event_string with error codes
more rigorously checked.

stat-shadow's prepare_metric() uses the metric-id to match the metricgroup
code.

As "metric-id=..." is added to all events, it is adding during testing
with the fake PMU.

This complicates pmu_str_check code as PE_PMU_EVENT_FAKE won't match as
part of a configuration.

The testing fake PMU case is fixed so that if a known qualifier with an
! is parsed then it isn't reported as a fake PMU.

This is sufficient to pass all testing but it and the original mechanism
are somewhat brittle.

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/20211015172132.1162559-17-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 4 insertions, 16 deletions

diff --git a/tools/perf/util/stat-shadow.c b/tools/perf/util/stat-shadow.c
index 20f1b9d0f272..69f3cf3b4a44 100644
--- a/tools/perf/util/stat-shadow.c
+++ b/tools/perf/util/stat-shadow.c
@@ -821,7 +821,7 @@ static int prepare_metric(struct evsel **metric_events,
 			  struct runtime_stat *st)
 {
 	double scale;
-	char *n, *pn;
+	char *n;
 	int i, j, ret;
 
 	for (i = 0; metric_events[i]; i++) {
@@ -844,23 +844,11 @@ static int prepare_metric(struct evsel **metric_events,
 			if (v->metric_other)
 				metric_total = v->metric_total;
 		}
-
-		n = strdup(metric_events[i]->name);
+		n = strdup(evsel__metric_id(metric_events[i]));
 		if (!n)
 			return -ENOMEM;
-		/*
-		 * This display code with --no-merge adds [cpu] postfixes.
-		 * These are not supported by the parser. Remove everything
-		 * after the space.
-		 */
-		pn = strchr(n, ' ');
-		if (pn)
-			*pn = 0;
-
-		if (metric_total)
-			expr__add_id_val(pctx, n, metric_total);
-		else
-			expr__add_id_val(pctx, n, avg_stats(stats)*scale);
+
+		expr__add_id_val(pctx, n, metric_total ? : avg_stats(stats) * scale);
 	}
 
 	for (j = 0; metric_refs && metric_refs[j].metric_name; j++) {