cloudflared-mirror/vendor/github.com/google/pprof/profile/merge.go

482 lines
12 KiB
Go

// Copyright 2014 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package profile
import (
"fmt"
"sort"
"strconv"
"strings"
)
// Compact performs garbage collection on a profile to remove any
// unreferenced fields. This is useful to reduce the size of a profile
// after samples or locations have been removed.
func (p *Profile) Compact() *Profile {
p, _ = Merge([]*Profile{p})
return p
}
// Merge merges all the profiles in profs into a single Profile.
// Returns a new profile independent of the input profiles. The merged
// profile is compacted to eliminate unused samples, locations,
// functions and mappings. Profiles must have identical profile sample
// and period types or the merge will fail. profile.Period of the
// resulting profile will be the maximum of all profiles, and
// profile.TimeNanos will be the earliest nonzero one. Merges are
// associative with the caveat of the first profile having some
// specialization in how headers are combined. There may be other
// subtleties now or in the future regarding associativity.
func Merge(srcs []*Profile) (*Profile, error) {
if len(srcs) == 0 {
return nil, fmt.Errorf("no profiles to merge")
}
p, err := combineHeaders(srcs)
if err != nil {
return nil, err
}
pm := &profileMerger{
p: p,
samples: make(map[sampleKey]*Sample, len(srcs[0].Sample)),
locations: make(map[locationKey]*Location, len(srcs[0].Location)),
functions: make(map[functionKey]*Function, len(srcs[0].Function)),
mappings: make(map[mappingKey]*Mapping, len(srcs[0].Mapping)),
}
for _, src := range srcs {
// Clear the profile-specific hash tables
pm.locationsByID = make(map[uint64]*Location, len(src.Location))
pm.functionsByID = make(map[uint64]*Function, len(src.Function))
pm.mappingsByID = make(map[uint64]mapInfo, len(src.Mapping))
if len(pm.mappings) == 0 && len(src.Mapping) > 0 {
// The Mapping list has the property that the first mapping
// represents the main binary. Take the first Mapping we see,
// otherwise the operations below will add mappings in an
// arbitrary order.
pm.mapMapping(src.Mapping[0])
}
for _, s := range src.Sample {
if !isZeroSample(s) {
pm.mapSample(s)
}
}
}
for _, s := range p.Sample {
if isZeroSample(s) {
// If there are any zero samples, re-merge the profile to GC
// them.
return Merge([]*Profile{p})
}
}
return p, nil
}
// Normalize normalizes the source profile by multiplying each value in profile by the
// ratio of the sum of the base profile's values of that sample type to the sum of the
// source profile's value of that sample type.
func (p *Profile) Normalize(pb *Profile) error {
if err := p.compatible(pb); err != nil {
return err
}
baseVals := make([]int64, len(p.SampleType))
for _, s := range pb.Sample {
for i, v := range s.Value {
baseVals[i] += v
}
}
srcVals := make([]int64, len(p.SampleType))
for _, s := range p.Sample {
for i, v := range s.Value {
srcVals[i] += v
}
}
normScale := make([]float64, len(baseVals))
for i := range baseVals {
if srcVals[i] == 0 {
normScale[i] = 0.0
} else {
normScale[i] = float64(baseVals[i]) / float64(srcVals[i])
}
}
p.ScaleN(normScale)
return nil
}
func isZeroSample(s *Sample) bool {
for _, v := range s.Value {
if v != 0 {
return false
}
}
return true
}
type profileMerger struct {
p *Profile
// Memoization tables within a profile.
locationsByID map[uint64]*Location
functionsByID map[uint64]*Function
mappingsByID map[uint64]mapInfo
// Memoization tables for profile entities.
samples map[sampleKey]*Sample
locations map[locationKey]*Location
functions map[functionKey]*Function
mappings map[mappingKey]*Mapping
}
type mapInfo struct {
m *Mapping
offset int64
}
func (pm *profileMerger) mapSample(src *Sample) *Sample {
s := &Sample{
Location: make([]*Location, len(src.Location)),
Value: make([]int64, len(src.Value)),
Label: make(map[string][]string, len(src.Label)),
NumLabel: make(map[string][]int64, len(src.NumLabel)),
NumUnit: make(map[string][]string, len(src.NumLabel)),
}
for i, l := range src.Location {
s.Location[i] = pm.mapLocation(l)
}
for k, v := range src.Label {
vv := make([]string, len(v))
copy(vv, v)
s.Label[k] = vv
}
for k, v := range src.NumLabel {
u := src.NumUnit[k]
vv := make([]int64, len(v))
uu := make([]string, len(u))
copy(vv, v)
copy(uu, u)
s.NumLabel[k] = vv
s.NumUnit[k] = uu
}
// Check memoization table. Must be done on the remapped location to
// account for the remapped mapping. Add current values to the
// existing sample.
k := s.key()
if ss, ok := pm.samples[k]; ok {
for i, v := range src.Value {
ss.Value[i] += v
}
return ss
}
copy(s.Value, src.Value)
pm.samples[k] = s
pm.p.Sample = append(pm.p.Sample, s)
return s
}
// key generates sampleKey to be used as a key for maps.
func (sample *Sample) key() sampleKey {
ids := make([]string, len(sample.Location))
for i, l := range sample.Location {
ids[i] = strconv.FormatUint(l.ID, 16)
}
labels := make([]string, 0, len(sample.Label))
for k, v := range sample.Label {
labels = append(labels, fmt.Sprintf("%q%q", k, v))
}
sort.Strings(labels)
numlabels := make([]string, 0, len(sample.NumLabel))
for k, v := range sample.NumLabel {
numlabels = append(numlabels, fmt.Sprintf("%q%x%x", k, v, sample.NumUnit[k]))
}
sort.Strings(numlabels)
return sampleKey{
strings.Join(ids, "|"),
strings.Join(labels, ""),
strings.Join(numlabels, ""),
}
}
type sampleKey struct {
locations string
labels string
numlabels string
}
func (pm *profileMerger) mapLocation(src *Location) *Location {
if src == nil {
return nil
}
if l, ok := pm.locationsByID[src.ID]; ok {
return l
}
mi := pm.mapMapping(src.Mapping)
l := &Location{
ID: uint64(len(pm.p.Location) + 1),
Mapping: mi.m,
Address: uint64(int64(src.Address) + mi.offset),
Line: make([]Line, len(src.Line)),
IsFolded: src.IsFolded,
}
for i, ln := range src.Line {
l.Line[i] = pm.mapLine(ln)
}
// Check memoization table. Must be done on the remapped location to
// account for the remapped mapping ID.
k := l.key()
if ll, ok := pm.locations[k]; ok {
pm.locationsByID[src.ID] = ll
return ll
}
pm.locationsByID[src.ID] = l
pm.locations[k] = l
pm.p.Location = append(pm.p.Location, l)
return l
}
// key generates locationKey to be used as a key for maps.
func (l *Location) key() locationKey {
key := locationKey{
addr: l.Address,
isFolded: l.IsFolded,
}
if l.Mapping != nil {
// Normalizes address to handle address space randomization.
key.addr -= l.Mapping.Start
key.mappingID = l.Mapping.ID
}
lines := make([]string, len(l.Line)*2)
for i, line := range l.Line {
if line.Function != nil {
lines[i*2] = strconv.FormatUint(line.Function.ID, 16)
}
lines[i*2+1] = strconv.FormatInt(line.Line, 16)
}
key.lines = strings.Join(lines, "|")
return key
}
type locationKey struct {
addr, mappingID uint64
lines string
isFolded bool
}
func (pm *profileMerger) mapMapping(src *Mapping) mapInfo {
if src == nil {
return mapInfo{}
}
if mi, ok := pm.mappingsByID[src.ID]; ok {
return mi
}
// Check memoization tables.
mk := src.key()
if m, ok := pm.mappings[mk]; ok {
mi := mapInfo{m, int64(m.Start) - int64(src.Start)}
pm.mappingsByID[src.ID] = mi
return mi
}
m := &Mapping{
ID: uint64(len(pm.p.Mapping) + 1),
Start: src.Start,
Limit: src.Limit,
Offset: src.Offset,
File: src.File,
BuildID: src.BuildID,
HasFunctions: src.HasFunctions,
HasFilenames: src.HasFilenames,
HasLineNumbers: src.HasLineNumbers,
HasInlineFrames: src.HasInlineFrames,
}
pm.p.Mapping = append(pm.p.Mapping, m)
// Update memoization tables.
pm.mappings[mk] = m
mi := mapInfo{m, 0}
pm.mappingsByID[src.ID] = mi
return mi
}
// key generates encoded strings of Mapping to be used as a key for
// maps.
func (m *Mapping) key() mappingKey {
// Normalize addresses to handle address space randomization.
// Round up to next 4K boundary to avoid minor discrepancies.
const mapsizeRounding = 0x1000
size := m.Limit - m.Start
size = size + mapsizeRounding - 1
size = size - (size % mapsizeRounding)
key := mappingKey{
size: size,
offset: m.Offset,
}
switch {
case m.BuildID != "":
key.buildIDOrFile = m.BuildID
case m.File != "":
key.buildIDOrFile = m.File
default:
// A mapping containing neither build ID nor file name is a fake mapping. A
// key with empty buildIDOrFile is used for fake mappings so that they are
// treated as the same mapping during merging.
}
return key
}
type mappingKey struct {
size, offset uint64
buildIDOrFile string
}
func (pm *profileMerger) mapLine(src Line) Line {
ln := Line{
Function: pm.mapFunction(src.Function),
Line: src.Line,
}
return ln
}
func (pm *profileMerger) mapFunction(src *Function) *Function {
if src == nil {
return nil
}
if f, ok := pm.functionsByID[src.ID]; ok {
return f
}
k := src.key()
if f, ok := pm.functions[k]; ok {
pm.functionsByID[src.ID] = f
return f
}
f := &Function{
ID: uint64(len(pm.p.Function) + 1),
Name: src.Name,
SystemName: src.SystemName,
Filename: src.Filename,
StartLine: src.StartLine,
}
pm.functions[k] = f
pm.functionsByID[src.ID] = f
pm.p.Function = append(pm.p.Function, f)
return f
}
// key generates a struct to be used as a key for maps.
func (f *Function) key() functionKey {
return functionKey{
f.StartLine,
f.Name,
f.SystemName,
f.Filename,
}
}
type functionKey struct {
startLine int64
name, systemName, fileName string
}
// combineHeaders checks that all profiles can be merged and returns
// their combined profile.
func combineHeaders(srcs []*Profile) (*Profile, error) {
for _, s := range srcs[1:] {
if err := srcs[0].compatible(s); err != nil {
return nil, err
}
}
var timeNanos, durationNanos, period int64
var comments []string
seenComments := map[string]bool{}
var defaultSampleType string
for _, s := range srcs {
if timeNanos == 0 || s.TimeNanos < timeNanos {
timeNanos = s.TimeNanos
}
durationNanos += s.DurationNanos
if period == 0 || period < s.Period {
period = s.Period
}
for _, c := range s.Comments {
if seen := seenComments[c]; !seen {
comments = append(comments, c)
seenComments[c] = true
}
}
if defaultSampleType == "" {
defaultSampleType = s.DefaultSampleType
}
}
p := &Profile{
SampleType: make([]*ValueType, len(srcs[0].SampleType)),
DropFrames: srcs[0].DropFrames,
KeepFrames: srcs[0].KeepFrames,
TimeNanos: timeNanos,
DurationNanos: durationNanos,
PeriodType: srcs[0].PeriodType,
Period: period,
Comments: comments,
DefaultSampleType: defaultSampleType,
}
copy(p.SampleType, srcs[0].SampleType)
return p, nil
}
// compatible determines if two profiles can be compared/merged.
// returns nil if the profiles are compatible; otherwise an error with
// details on the incompatibility.
func (p *Profile) compatible(pb *Profile) error {
if !equalValueType(p.PeriodType, pb.PeriodType) {
return fmt.Errorf("incompatible period types %v and %v", p.PeriodType, pb.PeriodType)
}
if len(p.SampleType) != len(pb.SampleType) {
return fmt.Errorf("incompatible sample types %v and %v", p.SampleType, pb.SampleType)
}
for i := range p.SampleType {
if !equalValueType(p.SampleType[i], pb.SampleType[i]) {
return fmt.Errorf("incompatible sample types %v and %v", p.SampleType, pb.SampleType)
}
}
return nil
}
// equalValueType returns true if the two value types are semantically
// equal. It ignores the internal fields used during encode/decode.
func equalValueType(st1, st2 *ValueType) bool {
return st1.Type == st2.Type && st1.Unit == st2.Unit
}