[PATCH v2 12/12] perf jevents: Add load event json to verify and allow fallbacks

[Ian Rogers]

Add a LoadEvents function that loads all event json files in a
directory. In the Event constructor ensure all events are defined in
the event json except for legacy events like "cycles". If the initial
event isn't found then legacy_event1 is used, and if that isn't found
legacy_event2 is used. This allows a single Event to have multiple
event names as models will often rename the same event over time. If
the event doesn't exist an exception is raised.

So that references to metrics can be added, add the MetricRef
class. This doesn't validate as an event name and so provides an
escape hatch for metrics to refer to each other.

Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
 tools/perf/pmu-events/amd_metrics.py   |  7 ++-
 tools/perf/pmu-events/arm64_metrics.py |  7 ++-
 tools/perf/pmu-events/intel_metrics.py |  7 ++-
 tools/perf/pmu-events/metric.py        | 77 +++++++++++++++++++++++++-
 4 files changed, 92 insertions(+), 6 deletions(-)

diff --git a/tools/perf/pmu-events/amd_metrics.py b/tools/perf/pmu-events/amd_metrics.py
index cb850ab1ed13..227f9b98c016 100755
--- a/tools/perf/pmu-events/amd_metrics.py
+++ b/tools/perf/pmu-events/amd_metrics.py
@@ -1,14 +1,19 @@
 #!/usr/bin/env python3
 # SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
-from metric import (JsonEncodeMetric, JsonEncodeMetricGroupDescriptions, MetricGroup)
+from metric import (JsonEncodeMetric, JsonEncodeMetricGroupDescriptions, LoadEvents,
+                    MetricGroup)
 import argparse
 import json
+import os
 
 parser = argparse.ArgumentParser(description="AMD perf json generator")
 parser.add_argument("-metricgroups", help="Generate metricgroups data", action='store_true')
 parser.add_argument("model", help="e.g. amdzen[123]")
 args = parser.parse_args()
 
+directory = f"{os.path.dirname(os.path.realpath(__file__))}/arch/x86/{args.model}/"
+LoadEvents(directory)
+
 all_metrics = MetricGroup("",[])
 
 if args.metricgroups:
diff --git a/tools/perf/pmu-events/arm64_metrics.py b/tools/perf/pmu-events/arm64_metrics.py
index a54fa8aae2fa..7cd0ebc0bd80 100755
--- a/tools/perf/pmu-events/arm64_metrics.py
+++ b/tools/perf/pmu-events/arm64_metrics.py
@@ -1,8 +1,10 @@
 #!/usr/bin/env python3
 # SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
-from metric import (JsonEncodeMetric, JsonEncodeMetricGroupDescriptions, MetricGroup)
+from metric import (JsonEncodeMetric, JsonEncodeMetricGroupDescriptions, LoadEvents,
+                    MetricGroup)
 import argparse
 import json
+import os
 
 parser = argparse.ArgumentParser(description="ARM perf json generator")
 parser.add_argument("-metricgroups", help="Generate metricgroups data", action='store_true')
@@ -10,6 +12,9 @@ parser.add_argument("vendor", help="e.g. arm")
 parser.add_argument("model", help="e.g. neoverse-n1")
 args = parser.parse_args()
 
+directory = f"{os.path.dirname(os.path.realpath(__file__))}/arch/arm64/{args.vendor}/{args.model}/"
+LoadEvents(directory)
+
 all_metrics = MetricGroup("",[])
 
 if args.metricgroups:
diff --git a/tools/perf/pmu-events/intel_metrics.py b/tools/perf/pmu-events/intel_metrics.py
index 8b67b9613ab5..4fbb31c9eccd 100755
--- a/tools/perf/pmu-events/intel_metrics.py
+++ b/tools/perf/pmu-events/intel_metrics.py
@@ -1,14 +1,19 @@
 #!/usr/bin/env python3
 # SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
-from metric import (JsonEncodeMetric, JsonEncodeMetricGroupDescriptions, MetricGroup)
+from metric import (JsonEncodeMetric, JsonEncodeMetricGroupDescriptions, LoadEvents,
+                    MetricGroup)
 import argparse
 import json
+import os
 
 parser = argparse.ArgumentParser(description="Intel perf json generator")
 parser.add_argument("-metricgroups", help="Generate metricgroups data", action='store_true')
 parser.add_argument("model", help="e.g. skylakex")
 args = parser.parse_args()
 
+directory = f"{os.path.dirname(os.path.realpath(__file__))}/arch/x86/{args.model}/"
+LoadEvents(directory)
+
 all_metrics = MetricGroup("",[])
 
 if args.metricgroups:
diff --git a/tools/perf/pmu-events/metric.py b/tools/perf/pmu-events/metric.py
index dd8fd06940e6..03312cd6d491 100644
--- a/tools/perf/pmu-events/metric.py
+++ b/tools/perf/pmu-events/metric.py
@@ -3,10 +3,50 @@
 import ast
 import decimal
 import json
+import os
 import re
 from enum import Enum
 from typing import Dict, List, Optional, Set, Tuple, Union
 
+all_events = set()
+
+def LoadEvents(directory: str) -> None:
+  """Populate a global set of all known events for the purpose of validating Event names"""
+  global all_events
+  all_events = {
+      "context\-switches",
+      "cycles",
+      "duration_time",
+      "instructions",
+      "l2_itlb_misses",
+  }
+  for file in os.listdir(os.fsencode(directory)):
+    filename = os.fsdecode(file)
+    if filename.endswith(".json"):
+      for x in json.load(open(f"{directory}/{filename}")):
+        if "EventName" in x:
+          all_events.add(x["EventName"])
+        elif "ArchStdEvent" in x:
+          all_events.add(x["ArchStdEvent"])
+
+
+def CheckEvent(name: str) -> bool:
+  """Check the event name exists in the set of all loaded events"""
+  global all_events
+  if len(all_events) == 0:
+    # No events loaded so assume any event is good.
+    return True
+
+  if ':' in name:
+    # Remove trailing modifier.
+    name = name[:name.find(':')]
+  elif '/' in name:
+    # Name could begin with a PMU or an event, for now assume it is good.
+    return True
+
+  return name in all_events
+
+
 class MetricConstraint(Enum):
   GROUPED_EVENTS = 0
   NO_GROUP_EVENTS = 1
@@ -317,9 +357,18 @@ def _FixEscapes(s: str) -> str:
 class Event(Expression):
   """An event in an expression."""
 
-  def __init__(self, name: str, legacy_name: str = ''):
-    self.name = _FixEscapes(name)
-    self.legacy_name = _FixEscapes(legacy_name)
+  def __init__(self, *args: str):
+    error = ""
+    for name in args:
+      if CheckEvent(name):
+        self.name = _FixEscapes(name)
+        return
+      if error:
+        error += " or " + name
+      else:
+        error = name
+    global all_events
+    raise Exception(f"No event {error} in:\n{all_events}")
 
   def ToPerfJson(self):
     result = re.sub('/', '@', self.name)
@@ -338,6 +387,28 @@ class Event(Expression):
     return self
 
 
+class MetricRef(Expression):
+  """A metric reference in an expression."""
+
+  def __init__(self, name: str):
+    self.name = _FixEscapes(name)
+
+  def ToPerfJson(self):
+    return self.name
+
+  def ToPython(self):
+    return f'MetricRef(r"{self.name}")'
+
+  def Simplify(self) -> Expression:
+    return self
+
+  def Equals(self, other: Expression) -> bool:
+    return isinstance(other, MetricRef) and self.name == other.name
+
+  def Substitute(self, name: str, expression: Expression) -> Expression:
+    return self
+
+
 class Constant(Expression):
   """A constant within the expression tree."""
 
-- 
2.44.0.278.ge034bb2e1d-goog