pgo.go

     1  // Copyright 2024 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Package pgo contains the compiler-agnostic portions of PGO profile handling.
     6  // Notably, parsing pprof profiles and serializing/deserializing from a custom
     7  // intermediate representation.
     8  package pgo
     9  
    10  // Profile contains the processed data from the PGO profile.
    11  type Profile struct {
    12  	// TotalWeight is the aggregated edge weights across the profile. This
    13  	// helps us determine the percentage threshold for hot/cold
    14  	// partitioning.
    15  	TotalWeight int64
    16  
    17  	// NamedEdgeMap contains all unique call edges in the profile and their
    18  	// edge weight.
    19  	NamedEdgeMap NamedEdgeMap
    20  }
    21  
    22  // NamedCallEdge identifies a call edge by linker symbol names and call site
    23  // offset.
    24  type NamedCallEdge struct {
    25  	CallerName     string
    26  	CalleeName     string
    27  	CallSiteOffset int // Line offset from function start line.
    28  }
    29  
    30  // NamedEdgeMap contains all unique call edges in the profile and their
    31  // edge weight.
    32  type NamedEdgeMap struct {
    33  	Weight map[NamedCallEdge]int64
    34  
    35  	// ByWeight lists all keys in Weight, sorted by edge weight from
    36  	// highest to lowest.
    37  	ByWeight []NamedCallEdge
    38  }
    39  
    40  func emptyProfile() *Profile {
    41  	// Initialize empty maps/slices for easier use without a requiring a
    42  	// nil check.
    43  	return &Profile{
    44  		NamedEdgeMap: NamedEdgeMap{
    45  			ByWeight: make([]NamedCallEdge, 0),
    46  			Weight:   make(map[NamedCallEdge]int64),
    47  		},
    48  	}
    49  }
    50  
    51  // WeightInPercentage converts profile weights to a percentage.
    52  func WeightInPercentage(value int64, total int64) float64 {
    53  	return (float64(value) / float64(total)) * 100
    54  }
    55  
    56
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