perf jevents: Mark metrics with experimental events as experimental

When metrics are made with experimental events it is desirable the
metric description also carries this information in case of metric
inaccuracies.

Suggested-by: Perry Taylor <perry.taylor@intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Thomas Falcon <thomas.falcon@intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Benjamin Gray <bgray@linux.ibm.com>
Cc: Caleb Biggers <caleb.biggers@intel.com>
Cc: Edward Baker <edward.baker@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jing Zhang <renyu.zj@linux.alibaba.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Leo Yan <leo.yan@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sandipan Das <sandipan.das@amd.com>
Cc: Weilin Wang <weilin.wang@intel.com>
Cc: Xu Yang <xu.yang_2@nxp.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/pmu-events/metric.py

@@ -10,11 +10,13 @@ from typing import Dict, List, Optional, Set, Tuple, Union
 
 all_pmus = set()
 all_events = set()
+experimental_events = set()
 
 def LoadEvents(directory: str) -> None:
   """Populate a global set of all known events for the purpose of validating Event names"""
   global all_pmus
   global all_events
+  global experimental_events
   all_events = {
       "context\\-switches",
       "cpu\\-cycles",
@@ -32,6 +34,8 @@ def LoadEvents(directory: str) -> None:
             all_pmus.add(x["Unit"])
           if "EventName" in x:
             all_events.add(x["EventName"])
+            if "Experimental" in x and x["Experimental"] == "1":
+              experimental_events.add(x["EventName"])
           elif "ArchStdEvent" in x:
             all_events.add(x["ArchStdEvent"])
       except json.decoder.JSONDecodeError:
@@ -61,6 +65,18 @@ def CheckEvent(name: str) -> bool:
   return name in all_events
 
 
+def IsExperimentalEvent(name: str) -> bool:
+  global experimental_events
+  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 not experimental.
+    return False
+
+  return name in experimental_events
+
+
 class MetricConstraint(Enum):
   GROUPED_EVENTS = 0
   NO_GROUP_EVENTS = 1
@@ -82,6 +98,10 @@ class Expression:
     """Returns a simplified version of self."""
     raise NotImplementedError()
 
+  def HasExperimentalEvents(self) -> bool:
+    """Are experimental events used in the expression?"""
+    raise NotImplementedError()
+
   def Equals(self, other) -> bool:
     """Returns true when two expressions are the same."""
     raise NotImplementedError()
@@ -249,6 +269,9 @@ class Operator(Expression):
 
     return Operator(self.operator, lhs, rhs)
 
+  def HasExperimentalEvents(self) -> bool:
+    return self.lhs.HasExperimentalEvents() or self.rhs.HasExperimentalEvents()
+
   def Equals(self, other: Expression) -> bool:
     if isinstance(other, Operator):
       return self.operator == other.operator and self.lhs.Equals(
@@ -297,6 +320,10 @@ class Select(Expression):
 
     return Select(true_val, cond, false_val)
 
+  def HasExperimentalEvents(self) -> bool:
+    return (self.cond.HasExperimentalEvents() or self.true_val.HasExperimentalEvents() or
+            self.false_val.HasExperimentalEvents())
+
   def Equals(self, other: Expression) -> bool:
     if isinstance(other, Select):
       return self.cond.Equals(other.cond) and self.false_val.Equals(
@@ -345,6 +372,9 @@ class Function(Expression):
 
     return Function(self.fn, lhs, rhs)
 
+  def HasExperimentalEvents(self) -> bool:
+    return self.lhs.HasExperimentalEvents() or (self.rhs and self.rhs.HasExperimentalEvents())
+
   def Equals(self, other: Expression) -> bool:
     if isinstance(other, Function):
       result = self.fn == other.fn and self.lhs.Equals(other.lhs)
@@ -384,6 +414,9 @@ class Event(Expression):
     global all_events
     raise Exception(f"No event {error} in:\n{all_events}")
 
+  def HasExperimentalEvents(self) -> bool:
+    return IsExperimentalEvent(self.name)
+
   def ToPerfJson(self):
     result = re.sub('/', '@', self.name)
     return result
@@ -416,6 +449,9 @@ class MetricRef(Expression):
   def Simplify(self) -> Expression:
     return self
 
+  def HasExperimentalEvents(self) -> bool:
+    return False
+
   def Equals(self, other: Expression) -> bool:
     return isinstance(other, MetricRef) and self.name == other.name
 
@@ -443,6 +479,9 @@ class Constant(Expression):
   def Simplify(self) -> Expression:
     return self
 
+  def HasExperimentalEvents(self) -> bool:
+    return False
+
   def Equals(self, other: Expression) -> bool:
     return isinstance(other, Constant) and self.value == other.value
 
@@ -465,6 +504,9 @@ class Literal(Expression):
   def Simplify(self) -> Expression:
     return self
 
+  def HasExperimentalEvents(self) -> bool:
+    return False
+
   def Equals(self, other: Expression) -> bool:
     return isinstance(other, Literal) and self.value == other.value
 
@@ -527,6 +569,8 @@ class Metric:
     self.name = name
     self.description = description
     self.expr = expr.Simplify()
+    if self.expr.HasExperimentalEvents():
+      self.description += " (metric should be considered experimental as it contains experimental events)."
     # Workraound valid_only_metric hiding certain metrics based on unit.
     scale_unit = scale_unit.replace('/sec', ' per sec')
     if scale_unit[0].isdigit():