perf jevents: Add model list option

This allows the set of generated jevents events and metrics be limited
to a subset of the model names. Appropriate if trying to minimize the
binary size where only a set of models are possible.
Reviewed-by: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Caleb Biggers <caleb.biggers@intel.com>
Cc: Florian Fischer <florian.fischer@muhq.space>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jing Zhang <renyu.zj@linux.alibaba.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Kang Minchul <tegongkang@gmail.com>
Cc: Kim Phillips <kim.phillips@amd.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Perry Taylor <perry.taylor@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Sandipan Das <sandipan.das@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Will Deacon <will@kernel.org>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lore.kernel.org/r/20230126233645.200509-12-irogers@google.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/pmu-events/Build

@@ -10,6 +10,7 @@ JEVENTS_PY	=  pmu-events/jevents.py
 ifeq ($(JEVENTS_ARCH),)
 JEVENTS_ARCH=$(SRCARCH)
 endif
+JEVENTS_MODEL ?= all
 
 #
 # Locate/process JSON files in pmu-events/arch/
@@ -23,5 +24,5 @@ $(OUTPUT)pmu-events/pmu-events.c: pmu-events/empty-pmu-events.c
 else
 $(OUTPUT)pmu-events/pmu-events.c: $(JSON) $(JSON_TEST) $(JEVENTS_PY) pmu-events/metric.py
 	$(call rule_mkdir)
-	$(Q)$(call echo-cmd,gen)$(PYTHON) $(JEVENTS_PY) $(JEVENTS_ARCH) pmu-events/arch $@
+	$(Q)$(call echo-cmd,gen)$(PYTHON) $(JEVENTS_PY) $(JEVENTS_ARCH) $(JEVENTS_MODEL) pmu-events/arch $@
 endif

tools/perf/pmu-events/jevents.py

@@ -599,6 +599,8 @@ const struct pmu_events_map pmu_events_map[] = {
             else:
               metric_tblname = 'NULL'
               metric_size = '0'
+            if event_size == '0' and metric_size == '0':
+              continue
             cpuid = row[0].replace('\\', '\\\\')
             _args.output_file.write(f"""{{
 \t.arch = "{arch}",
@@ -888,12 +890,24 @@ def main() -> None:
           action: Callable[[Sequence[str], os.DirEntry], None]) -> None:
     """Replicate the directory/file walking behavior of C's file tree walk."""
     for item in os.scandir(path):
+      if _args.model != 'all' and item.is_dir():
+        # Check if the model matches one in _args.model.
+        if len(parents) == _args.model.split(',')[0].count('/'):
+          # We're testing the correct directory.
+          item_path = '/'.join(parents) + ('/' if len(parents) > 0 else '') + item.name
+          if 'test' not in item_path and item_path not in _args.model.split(','):
+            continue
       action(parents, item)
       if item.is_dir():
         ftw(item.path, parents + [item.name], action)
 
   ap = argparse.ArgumentParser()
   ap.add_argument('arch', help='Architecture name like x86')
+  ap.add_argument('model', help='''Select a model such as skylake to
+reduce the code size.  Normally set to "all". For architectures like
+ARM64 with an implementor/model, the model must include the implementor
+such as "arm/cortex-a34".''',
+                  default='all')
   ap.add_argument(
       'starting_dir',
       type=dir_path,