forked from TrueCloudLab/restic
143 lines
3.6 KiB
Go
143 lines
3.6 KiB
Go
// Copyright 2017 Google Inc. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package profiler
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import (
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"bytes"
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"regexp"
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"runtime"
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"strings"
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"github.com/google/pprof/profile"
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)
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var shouldAssumeSymbolized = isSymbolizedGoVersion(runtime.Version())
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type function interface {
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Name() string
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FileLine(pc uintptr) (string, int)
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}
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// funcForPC is a wrapper for runtime.FuncForPC. Defined as var for testing.
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var funcForPC = func(pc uintptr) function {
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if f := runtime.FuncForPC(pc); f != nil {
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return f
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}
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return nil
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}
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// parseAndSymbolize parses a profile from a buffer, symbolizes it
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// if it's not yet symbolized, and writes the profile back as a
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// gzip-compressed marshaled protobuf.
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func parseAndSymbolize(data *bytes.Buffer) error {
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p, err := profile.ParseData(data.Bytes())
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if err != nil {
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return err
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}
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// Do nothing if the profile is already symbolized.
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if symbolized(p) {
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return nil
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}
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// Clear the profile functions to avoid creating duplicates.
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p.Function = nil
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symbolize(p)
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data.Reset()
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return p.Write(data)
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}
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// isSymbolizedGoVersion returns true if Go version equals to or is
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// higher than Go 1.9. Starting Go 1.9 the profiles are symbolized
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// by runtime/pprof.
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func isSymbolizedGoVersion(goVersion string) bool {
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r, err := regexp.Compile(`go(1\.9|1\.[1-9][0-9]|[2-9]).*`)
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if err == nil && r.MatchString(goVersion) {
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return true
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}
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return false
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}
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// symbolized checks if all locations have symbolized function
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// information.
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func symbolized(p *profile.Profile) bool {
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for _, l := range p.Location {
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if len(l.Line) == 0 || l.Line[0].Function == nil {
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return false
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}
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}
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return true
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}
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func symbolize(p *profile.Profile) {
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fns := profileFunctionMap{}
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for _, l := range p.Location {
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pc := uintptr(l.Address)
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f := funcForPC(pc)
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if f == nil {
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continue
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}
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file, lineno := f.FileLine(pc)
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l.Line = []profile.Line{
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{
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Function: fns.findOrAddFunction(f.Name(), file, p),
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Line: int64(lineno),
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},
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}
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}
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// Trim runtime functions. Always hide runtime.goexit. Other runtime
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// functions are only hidden for heap profile when they appear at the beginning.
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isHeapProfile := p.PeriodType != nil && p.PeriodType.Type == "space"
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for _, s := range p.Sample {
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show := !isHeapProfile
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var i int
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for _, l := range s.Location {
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if len(l.Line) > 0 && l.Line[0].Function != nil {
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name := l.Line[0].Function.Name
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if name == "runtime.goexit" || !show && strings.HasPrefix(name, "runtime.") {
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continue
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}
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}
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show = true
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s.Location[i] = l
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i++
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}
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// If all locations of a sample are trimmed, keep the root location.
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if i == 0 && len(s.Location) > 0 {
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s.Location[0] = s.Location[len(s.Location)-1]
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i = 1
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}
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s.Location = s.Location[:i]
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}
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}
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type profileFunctionMap map[profile.Function]*profile.Function
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func (fns profileFunctionMap) findOrAddFunction(name, filename string, p *profile.Profile) *profile.Function {
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f := profile.Function{
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Name: name,
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SystemName: name,
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Filename: filename,
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}
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if fp := fns[f]; fp != nil {
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return fp
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}
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fp := new(profile.Function)
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fns[f] = fp
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*fp = f
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fp.ID = uint64(len(p.Function) + 1)
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p.Function = append(p.Function, fp)
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return fp
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}
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