# SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
"""Parse or generate representations of perf metrics."""
import ast
import decimal
import json
import re
from typing import Dict, List, Optional, Set, Tuple, Union
class Expression:
"""Abstract base class of elements in a metric expression."""
def ToPerfJson(self) -> str:
"""Returns a perf json file encoded representation."""
raise NotImplementedError()
def ToPython(self) -> str:
"""Returns a python expr parseable representation."""
raise NotImplementedError()
def Simplify(self):
"""Returns a simplified version of self."""
raise NotImplementedError()
def Equals(self, other) -> bool:
"""Returns true when two expressions are the same."""
raise NotImplementedError()
def Substitute(self, name: str, expression: 'Expression') -> 'Expression':
raise NotImplementedError()
def __str__(self) -> str:
return self.ToPerfJson()
def __or__(self, other: Union[int, float, 'Expression']) -> 'Operator':
return Operator('|', self, other)
def __ror__(self, other: Union[int, float, 'Expression']) -> 'Operator':
return Operator('|', other, self)
def __xor__(self, other: Union[int, float, 'Expression']) -> 'Operator':
return Operator('^', self, other)
def __and__(self, other: Union[int, float, 'Expression']) -> 'Operator':
return Operator('&', self, other)
def __rand__(self, other: Union[int, float, 'Expression']) -> 'Operator':
return Operator('&', other, self)
def __lt__(self, other: Union[int, float, 'Expression']) -> 'Operator':
return Operator('<', self, other)
def __gt__(self, other: Union[int, float, 'Expression']) -> 'Operator':
return Operator('>', self, other)
def __add__(self, other: Union[int, float, 'Expression']) -> 'Operator':
return Operator('+', self, other)
def __radd__(self, other: Union[int, float, 'Expression']) -> 'Operator':
return Operator('+', other, self)
def __sub__(self, other: Union[int, float, 'Expression']) -> 'Operator':
return Operator('-', self, other)
def __rsub__(self, other: Union[int, float, 'Expression']) -> 'Operator':
return Operator('-', other, self)
def __mul__(self, other: Union[int, float, 'Expression']) -> 'Operator':
return Operator('*', self, other)
def __rmul__(self, other: Union[int, float, 'Expression']) -> 'Operator':
return Operator('*', other, self)
def __truediv__(self, other: Union[int, float, 'Expression']) -> 'Operator':
return Operator('/', self, other)
def __rtruediv__(self, other: Union[int, float, 'Expression']) -> 'Operator':
return Operator('/', other, self)
def __mod__(self, other: Union[int, float, 'Expression']) -> 'Operator':
return Operator('%', self, other)
def _Constify(val: Union[bool, int, float, Expression]) -> Expression:
"""Used to ensure that the nodes in the expression tree are all Expression."""
if isinstance(val, bool):
return Constant(1 if val else 0)
if isinstance(val, (int, float)):
return Constant(val)
return val
# Simple lookup for operator precedence, used to avoid unnecessary
# brackets. Precedence matches that of the simple expression parser
# but differs from python where comparisons are lower precedence than
# the bitwise &, ^, | but not the logical versions that the expression
# parser doesn't have.
_PRECEDENCE = {
'|': 0,
'^': 1,
'&': 2,
'<': 3,
'>': 3,
'+': 4,
'-': 4,
'*': 5,
'/': 5,
'%': 5,
}
class Operator(Expression):
"""Represents a binary operator in the parse tree."""
def __init__(self, operator: str, lhs: Union[int, float, Expression],
rhs: Union[int, float, Expression]):
self.operator = operator
self.lhs = _Constify(lhs)
self.rhs = _Constify(rhs)
def Bracket(self,
other: Expression,
other_str: str,
rhs: bool = False) -> str:
"""If necessary brackets the given other value.
If ``other`` is an operator then a bracket is necessary when
this/self operator has higher precedence. Consider: '(a + b) * c',
``other_str`` will be 'a + b'. A bracket is necessary as without
the bracket 'a + b * c' will evaluate 'b * c' first. However, '(a
* b) + c' doesn't need a bracket as 'a * b' will always be
evaluated first. For 'a / (b * c)' (ie the same precedence level
operations) then we add the bracket to best match the original
input, but not for '(a / b) * c' where the bracket is unnecessary.
Args:
other (Expression): is a lhs or rhs operator
other_str (str): ``other`` in the appropriate string form
rhs (bool): is ``other`` on the RHS
Returns:
str: possibly bracketed other_str
"""
if isinstance(other, Operator):
if _PRECEDENCE.get(self.operator, -1) > _PRECEDENCE.get(
other.operator, -1):
return f'({other_str})'
if rhs and _PRECEDENCE.get(self.operator, -1) == _PRECEDENCE.get(
other.operator, -1):
return f'({other_str})'
return other_str
def ToPerfJson(self):
return (f'{self.Bracket(self.lhs, self.lhs.ToPerfJson())} {self.operator} '
f'{self.Bracket(self.rhs, self.rhs.ToPerfJson(), True)}')
def ToPython(self):
return (f'{self.Bracket(self.lhs, self.lhs.ToPython())} {self.operator} '
f'{self.Bracket(self.rhs, self.rhs.ToPython(), True)}')
def Simplify(self) -> Expression:
lhs = self.lhs.Simplify()
rhs = self.rhs.Simplify()
if isinstance(lhs, Constant) and isinstance(rhs, Constant):
return Constant(ast.literal_eval(lhs + self.operator + rhs))
if isinstance(self.lhs, Constant):
if self.operator in ('+', '|') and lhs.value == '0':
return rhs
# Simplify multiplication by 0 except for the slot event which
# is deliberately introduced using this pattern.
if self.operator == '*' and lhs.value == '0' and (
not isinstance(rhs, Event) or 'slots' not in rhs.name.lower()):
return Constant(0)
if self.operator == '*' and lhs.value == '1':
return rhs
if isinstance(rhs, Constant):
if self.operator in ('+', '|') and rhs.value == '0':
return lhs
if self.operator == '*' and rhs.value == '0':
return Constant(0)
if self.operator == '*' and self.rhs.value == '1':
return lhs
return Operator(self.operator, lhs, rhs)
def Equals(self, other: Expression) -> bool:
if isinstance(other, Operator):
return self.operator == other.operator and self.lhs.Equals(
other.lhs) and self.rhs.Equals(other.rhs)
return False
def Substitute(self, name: str, expression: Expression) -> Expression:
if self.Equals(expression):
return Event(name)
lhs = self.lhs.Substitute(name, expression)
rhs = None
if self.rhs:
rhs = self.rhs.Substitute(name, expression)
return Operator(self.operator, lhs, rhs)
class Select(Expression):
"""Represents a select ternary in the parse tree."""
def __init__(self, true_val: Union[int, float, Expression],
cond: Union[int, float, Expression],
false_val: Union[int, float, Expression]):
self.true_val = _Constify(true_val)
self.cond = _Constify(cond)
self.false_val = _Constify(false_val)
def ToPerfJson(self):
true_str = self.true_val.ToPerfJson()
cond_str = self.cond.ToPerfJson()
false_str = self.false_val.ToPerfJson()
return f'({true_str} if {cond_str} else {false_str})'
def ToPython(self):
return (f'Select({self.true_val.ToPython()}, {self.cond.ToPython()}, '
f'{self.false_val.ToPython()})')
def Simplify(self) -> Expression:
cond = self.cond.Simplify()
true_val = self.true_val.Simplify()
false_val = self.false_val.Simplify()
if isinstance(cond, Constant):
return false_val if cond.value == '0' else true_val
if true_val.Equals(false_val):
return true_val
return Select(true_val, cond, false_val)
def Equals(self, other: Expression) -> bool:
if isinstance(other, Select):
return self.cond.Equals(other.cond) and self.false_val.Equals(
other.false_val) and self.true_val.Equals(other.true_val)
return False
def Substitute(self, name: str, expression: Expression) -> Expression:
if self.Equals(expression):
return Event(name)
true_val = self.true_val.Substitute(name, expression)
cond = self.cond.Substitute(name, expression)
false_val = self.false_val.Substitute(name, expression)
return Select(true_val, cond, false_val)
class Function(Expression):
"""A function in an expression like min, max, d_ratio."""
def __init__(self,
fn: str,
lhs: Union[int, float, Expression],
rhs: Optional[Union[int, float, Expression]] = None):
self.fn = fn
self.lhs = _Constify(lhs)
self.rhs = _Constify(rhs)
def ToPerfJson(self):
if self.rhs:
return f'{self.fn}({self.lhs.ToPerfJson()}, {self.rhs.ToPerfJson()})'
return f'{self.fn}({self.lhs.ToPerfJson()})'
def ToPython(self):
if self.rhs:
return f'{self.fn}({self.lhs.ToPython()}, {self.rhs.ToPython()})'
return f'{self.fn}({self.lhs.ToPython()})'
def Simplify(self) -> Expression:
lhs = self.lhs.Simplify()
rhs = self.rhs.Simplify() if self.rhs else None
if isinstance(lhs, Constant) and isinstance(rhs, Constant):
if self.fn == 'd_ratio':
if rhs.value == '0':
return Constant(0)
Constant(ast.literal_eval(f'{lhs} / {rhs}'))
return Constant(ast.literal_eval(f'{self.fn}({lhs}, {rhs})'))
return Function(self.fn, lhs, rhs)
def Equals(self, other: Expression) -> bool:
if isinstance(other, Function):
result = self.fn == other.fn and self.lhs.Equals(other.lhs)
if self.rhs:
result = result and self.rhs.Equals(other.rhs)
return result
return False
def Substitute(self, name: str, expression: Expression) -> Expression:
if self.Equals(expression):
return Event(name)
lhs = self.lhs.Substitute(name, expression)
rhs = None
if self.rhs:
rhs = self.rhs.Substitute(name, expression)
return Function(self.fn, lhs, rhs)
def _FixEscapes(s: str) -> str:
s = re.sub(r'([^\\]),', r'\1\\,', s)
return re.sub(r'([^\\])=', r'\1\\=', s)
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 ToPerfJson(self):
result = re.sub('/', '@', self.name)
return result
def ToPython(self):
return f'Event(r"{self.name}")'
def Simplify(self) -> Expression:
return self
def Equals(self, other: Expression) -> bool:
return isinstance(other, Event) and self.name == other.name
def Substitute(self, name: str, expression: Expression) -> Expression:
return self
class Constant(Expression):
"""A constant within the expression tree."""
def __init__(self, value: Union[float, str]):
ctx = decimal.Context()
ctx.prec = 20
dec = ctx.create_decimal(repr(value) if isinstance(value, float) else value)
self.value = dec.normalize().to_eng_string()
self.value = self.value.replace('+', '')
self.value = self.value.replace('E', 'e')
def ToPerfJson(self):
return self.value
def ToPython(self):
return f'Constant({self.value})'
def Simplify(self) -> Expression:
return self
def Equals(self, other: Expression) -> bool:
return isinstance(other, Constant) and self.value == other.value
def Substitute(self, name: str, expression: Expression) -> Expression:
return self
class Literal(Expression):
"""A runtime literal within the expression tree."""
def __init__(self, value: str):
self.value = value
def ToPerfJson(self):
return self.value
def ToPython(self):
return f'Literal({self.value})'
def Simplify(self) -> Expression:
return self
def Equals(self, other: Expression) -> bool:
return isinstance(other, Literal) and self.value == other.value
def Substitute(self, name: str, expression: Expression) -> Expression:
return self
def min(lhs: Union[int, float, Expression], rhs: Union[int, float,
Expression]) -> Function:
# pylint: disable=redefined-builtin
# pylint: disable=invalid-name
return Function('min', lhs, rhs)
def max(lhs: Union[int, float, Expression], rhs: Union[int, float,
Expression]) -> Function:
# pylint: disable=redefined-builtin
# pylint: disable=invalid-name
return Function('max', lhs, rhs)
def d_ratio(lhs: Union[int, float, Expression],
rhs: Union[int, float, Expression]) -> Function:
# pylint: disable=redefined-builtin
# pylint: disable=invalid-name
return Function('d_ratio', lhs, rhs)
def source_count(event: Event) -> Function:
# pylint: disable=redefined-builtin
# pylint: disable=invalid-name
return Function('source_count', event)
def has_event(event: Event) -> Function:
# pylint: disable=redefined-builtin
# pylint: disable=invalid-name
return Function('has_event', event)
def strcmp_cpuid_str(cpuid: Event) -> Function:
# pylint: disable=redefined-builtin
# pylint: disable=invalid-name
return Function('strcmp_cpuid_str', cpuid)
class Metric:
"""An individual metric that will specifiable on the perf command line."""
groups: Set[str]
expr: Expression
scale_unit: str
constraint: bool
def __init__(self,
name: str,
description: str,
expr: Expression,
scale_unit: str,
constraint: bool = False):
self.name = name
self.description = description
self.expr = expr.Simplify()
# Workraound valid_only_metric hiding certain metrics based on unit.
scale_unit = scale_unit.replace('/sec', ' per sec')
if scale_unit[0].isdigit():
self.scale_unit = scale_unit
else:
self.scale_unit = f'1{scale_unit}'
self.constraint = constraint
self.groups = set()
def __lt__(self, other):
"""Sort order."""
return self.name < other.name
def AddToMetricGroup(self, group):
"""Callback used when being added to a MetricGroup."""
self.groups.add(group.name)
def Flatten(self) -> Set['Metric']:
"""Return a leaf metric."""
return set([self])
def ToPerfJson(self) -> Dict[str, str]:
"""Return as dictionary for Json generation."""
result = {
'MetricName': self.name,
'MetricGroup': ';'.join(sorted(self.groups)),
'BriefDescription': self.description,
'MetricExpr': self.expr.ToPerfJson(),
'ScaleUnit': self.scale_unit
}
if self.constraint:
result['MetricConstraint'] = 'NO_NMI_WATCHDOG'
return result
class _MetricJsonEncoder(json.JSONEncoder):
"""Special handling for Metric objects."""
def default(self, o):
if isinstance(o, Metric):
return o.ToPerfJson()
return json.JSONEncoder.default(self, o)
class MetricGroup:
"""A group of metrics.
Metric groups may be specificd on the perf command line, but within
the json they aren't encoded. Metrics may be in multiple groups
which can facilitate arrangements similar to trees.
"""
def __init__(self, name: str, metric_list: List[Union[Metric,
'MetricGroup']]):
self.name = name
self.metric_list = metric_list
for metric in metric_list:
metric.AddToMetricGroup(self)
def AddToMetricGroup(self, group):
"""Callback used when a MetricGroup is added into another."""
for metric in self.metric_list:
metric.AddToMetricGroup(group)
def Flatten(self) -> Set[Metric]:
"""Returns a set of all leaf metrics."""
result = set()
for x in self.metric_list:
result = result.union(x.Flatten())
return result
def ToPerfJson(self) -> str:
return json.dumps(sorted(self.Flatten()), indent=2, cls=_MetricJsonEncoder)
def __str__(self) -> str:
return self.ToPerfJson()
class _RewriteIfExpToSelect(ast.NodeTransformer):
"""Transformer to convert if-else nodes to Select expressions."""
def visit_IfExp(self, node):
# pylint: disable=invalid-name
self.generic_visit(node)
call = ast.Call(
func=ast.Name(id='Select', ctx=ast.Load()),
args=[node.body, node.test, node.orelse],
keywords=[])
ast.copy_location(call, node.test)
return call
def ParsePerfJson(orig: str) -> Expression:
"""A simple json metric expression decoder.
Converts a json encoded metric expression by way of python's ast and
eval routine. First tokens are mapped to Event calls, then
accidentally converted keywords or literals are mapped to their
appropriate calls. Python's ast is used to match if-else that can't
be handled via operator overloading. Finally the ast is evaluated.
Args:
orig (str): String to parse.
Returns:
Expression: The parsed string.
"""
# pylint: disable=eval-used
py = orig.strip()
# First try to convert everything that looks like a string (event name) into Event(r"EVENT_NAME").
# This isn't very selective so is followed up by converting some unwanted conversions back again
py = re.sub(r'([a-zA-Z][^-+/\* \\\(\),]*(?:\\.[^-+/\* \\\(\),]*)*)',
r'Event(r"\1")', py)
# If it started with a # it should have been a literal, rather than an event name
py = re.sub(r'#Event\(r"([^"]*)"\)', r'Literal("#\1")', py)
# Convert accidentally converted hex constants ("0Event(r"xDEADBEEF)"") back to a constant,
# but keep it wrapped in Event(), otherwise Python drops the 0x prefix and it gets interpreted as
# a double by the Bison parser
py = re.sub(r'0Event\(r"[xX]([0-9a-fA-F]*)"\)', r'Event("0x\1")', py)
# Convert accidentally converted scientific notation constants back
py = re.sub(r'([0-9]+)Event\(r"(e[0-9]+)"\)', r'\1\2', py)
# Convert all the known keywords back from events to just the keyword
keywords = ['if', 'else', 'min', 'max', 'd_ratio', 'source_count', 'has_event', 'strcmp_cpuid_str']
for kw in keywords:
py = re.sub(rf'Event\(r"{kw}"\)', kw, py)
try:
parsed = ast.parse(py, mode='eval')
except SyntaxError as e:
raise SyntaxError(f'Parsing expression:\n{orig}') from e
_RewriteIfExpToSelect().visit(parsed)
parsed = ast.fix_missing_locations(parsed)
return _Constify(eval(compile(parsed, orig, 'eval')))
def RewriteMetricsInTermsOfOthers(metrics: List[Tuple[str, str, Expression]]
)-> Dict[Tuple[str, str], Expression]:
"""Shorten metrics by rewriting in terms of others.
Args:
metrics (list): pmus, metric names and their expressions.
Returns:
Dict: mapping from a pmu, metric name pair to a shortened expression.
"""
updates: Dict[Tuple[str, str], Expression] = dict()
for outer_pmu, outer_name, outer_expression in metrics:
if outer_pmu is None:
outer_pmu = 'cpu'
updated = outer_expression
while True:
for inner_pmu, inner_name, inner_expression in metrics:
if inner_pmu is None:
inner_pmu = 'cpu'
if inner_pmu.lower() != outer_pmu.lower():
continue
if inner_name.lower() == outer_name.lower():
continue
if (inner_pmu, inner_name) in updates:
inner_expression = updates[(inner_pmu, inner_name)]
updated = updated.Substitute(inner_name, inner_expression)
if updated.Equals(outer_expression):
break
if (outer_pmu, outer_name) in updates and updated.Equals(updates[(outer_pmu, outer_name)]):
break
updates[(outer_pmu, outer_name)] = updated
return updates
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