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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>