1 files changed, 673 insertions, 0 deletions
diff --git a/src/runtime/pprof/pprof.go b/src/runtime/pprof/pprof.go
new file mode 100644
index 000000000..236de54f3
--- /dev/null
+++ b/src/runtime/pprof/pprof.go
@@ -0,0 +1,673 @@
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package pprof writes runtime profiling data in the format expected
+// by the pprof visualization tool.
+// For more information about pprof, see
+// http://code.google.com/p/google-perftools/.
+package pprof
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"runtime"
+	"sort"
+	"strings"
+	"sync"
+	"text/tabwriter"
+)
+
+// BUG(rsc): Profiles are incomplete and inaccurate on NetBSD and OS X.
+// See http://golang.org/issue/6047 for details.
+
+// A Profile is a collection of stack traces showing the call sequences
+// that led to instances of a particular event, such as allocation.
+// Packages can create and maintain their own profiles; the most common
+// use is for tracking resources that must be explicitly closed, such as files
+// or network connections.
+//
+// A Profile's methods can be called from multiple goroutines simultaneously.
+//
+// Each Profile has a unique name.  A few profiles are predefined:
+//
+//	goroutine    - stack traces of all current goroutines
+//	heap         - a sampling of all heap allocations
+//	threadcreate - stack traces that led to the creation of new OS threads
+//	block        - stack traces that led to blocking on synchronization primitives
+//
+// These predefined profiles maintain themselves and panic on an explicit
+// Add or Remove method call.
+//
+// The CPU profile is not available as a Profile.  It has a special API,
+// the StartCPUProfile and StopCPUProfile functions, because it streams
+// output to a writer during profiling.
+//
+type Profile struct {
+	name  string
+	mu    sync.Mutex
+	m     map[interface{}][]uintptr
+	count func() int
+	write func(io.Writer, int) error
+}
+
+// profiles records all registered profiles.
+var profiles struct {
+	mu sync.Mutex
+	m  map[string]*Profile
+}
+
+var goroutineProfile = &Profile{
+	name:  "goroutine",
+	count: countGoroutine,
+	write: writeGoroutine,
+}
+
+var threadcreateProfile = &Profile{
+	name:  "threadcreate",
+	count: countThreadCreate,
+	write: writeThreadCreate,
+}
+
+var heapProfile = &Profile{
+	name:  "heap",
+	count: countHeap,
+	write: writeHeap,
+}
+
+var blockProfile = &Profile{
+	name:  "block",
+	count: countBlock,
+	write: writeBlock,
+}
+
+func lockProfiles() {
+	profiles.mu.Lock()
+	if profiles.m == nil {
+		// Initial built-in profiles.
+		profiles.m = map[string]*Profile{
+			"goroutine":    goroutineProfile,
+			"threadcreate": threadcreateProfile,
+			"heap":         heapProfile,
+			"block":        blockProfile,
+		}
+	}
+}
+
+func unlockProfiles() {
+	profiles.mu.Unlock()
+}
+
+// NewProfile creates a new profile with the given name.
+// If a profile with that name already exists, NewProfile panics.
+// The convention is to use a 'import/path.' prefix to create
+// separate name spaces for each package.
+func NewProfile(name string) *Profile {
+	lockProfiles()
+	defer unlockProfiles()
+	if name == "" {
+		panic("pprof: NewProfile with empty name")
+	}
+	if profiles.m[name] != nil {
+		panic("pprof: NewProfile name already in use: " + name)
+	}
+	p := &Profile{
+		name: name,
+		m:    map[interface{}][]uintptr{},
+	}
+	profiles.m[name] = p
+	return p
+}
+
+// Lookup returns the profile with the given name, or nil if no such profile exists.
+func Lookup(name string) *Profile {
+	lockProfiles()
+	defer unlockProfiles()
+	return profiles.m[name]
+}
+
+// Profiles returns a slice of all the known profiles, sorted by name.
+func Profiles() []*Profile {
+	lockProfiles()
+	defer unlockProfiles()
+
+	var all []*Profile
+	for _, p := range profiles.m {
+		all = append(all, p)
+	}
+
+	sort.Sort(byName(all))
+	return all
+}
+
+type byName []*Profile
+
+func (x byName) Len() int           { return len(x) }
+func (x byName) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }
+func (x byName) Less(i, j int) bool { return x[i].name < x[j].name }
+
+// Name returns this profile's name, which can be passed to Lookup to reobtain the profile.
+func (p *Profile) Name() string {
+	return p.name
+}
+
+// Count returns the number of execution stacks currently in the profile.
+func (p *Profile) Count() int {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	if p.count != nil {
+		return p.count()
+	}
+	return len(p.m)
+}
+
+// Add adds the current execution stack to the profile, associated with value.
+// Add stores value in an internal map, so value must be suitable for use as
+// a map key and will not be garbage collected until the corresponding
+// call to Remove.  Add panics if the profile already contains a stack for value.
+//
+// The skip parameter has the same meaning as runtime.Caller's skip
+// and controls where the stack trace begins.  Passing skip=0 begins the
+// trace in the function calling Add.  For example, given this
+// execution stack:
+//
+//	Add
+//	called from rpc.NewClient
+//	called from mypkg.Run
+//	called from main.main
+//
+// Passing skip=0 begins the stack trace at the call to Add inside rpc.NewClient.
+// Passing skip=1 begins the stack trace at the call to NewClient inside mypkg.Run.
+//
+func (p *Profile) Add(value interface{}, skip int) {
+	if p.name == "" {
+		panic("pprof: use of uninitialized Profile")
+	}
+	if p.write != nil {
+		panic("pprof: Add called on built-in Profile " + p.name)
+	}
+
+	stk := make([]uintptr, 32)
+	n := runtime.Callers(skip+1, stk[:])
+
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	if p.m[value] != nil {
+		panic("pprof: Profile.Add of duplicate value")
+	}
+	p.m[value] = stk[:n]
+}
+
+// Remove removes the execution stack associated with value from the profile.
+// It is a no-op if the value is not in the profile.
+func (p *Profile) Remove(value interface{}) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	delete(p.m, value)
+}
+
+// WriteTo writes a pprof-formatted snapshot of the profile to w.
+// If a write to w returns an error, WriteTo returns that error.
+// Otherwise, WriteTo returns nil.
+//
+// The debug parameter enables additional output.
+// Passing debug=0 prints only the hexadecimal addresses that pprof needs.
+// Passing debug=1 adds comments translating addresses to function names
+// and line numbers, so that a programmer can read the profile without tools.
+//
+// The predefined profiles may assign meaning to other debug values;
+// for example, when printing the "goroutine" profile, debug=2 means to
+// print the goroutine stacks in the same form that a Go program uses
+// when dying due to an unrecovered panic.
+func (p *Profile) WriteTo(w io.Writer, debug int) error {
+	if p.name == "" {
+		panic("pprof: use of zero Profile")
+	}
+	if p.write != nil {
+		return p.write(w, debug)
+	}
+
+	// Obtain consistent snapshot under lock; then process without lock.
+	var all [][]uintptr
+	p.mu.Lock()
+	for _, stk := range p.m {
+		all = append(all, stk)
+	}
+	p.mu.Unlock()
+
+	// Map order is non-deterministic; make output deterministic.
+	sort.Sort(stackProfile(all))
+
+	return printCountProfile(w, debug, p.name, stackProfile(all))
+}
+
+type stackProfile [][]uintptr
+
+func (x stackProfile) Len() int              { return len(x) }
+func (x stackProfile) Stack(i int) []uintptr { return x[i] }
+func (x stackProfile) Swap(i, j int)         { x[i], x[j] = x[j], x[i] }
+func (x stackProfile) Less(i, j int) bool {
+	t, u := x[i], x[j]
+	for k := 0; k < len(t) && k < len(u); k++ {
+		if t[k] != u[k] {
+			return t[k] < u[k]
+		}
+	}
+	return len(t) < len(u)
+}
+
+// A countProfile is a set of stack traces to be printed as counts
+// grouped by stack trace.  There are multiple implementations:
+// all that matters is that we can find out how many traces there are
+// and obtain each trace in turn.
+type countProfile interface {
+	Len() int
+	Stack(i int) []uintptr
+}
+
+// printCountProfile prints a countProfile at the specified debug level.
+func printCountProfile(w io.Writer, debug int, name string, p countProfile) error {
+	b := bufio.NewWriter(w)
+	var tw *tabwriter.Writer
+	w = b
+	if debug > 0 {
+		tw = tabwriter.NewWriter(w, 1, 8, 1, '\t', 0)
+		w = tw
+	}
+
+	fmt.Fprintf(w, "%s profile: total %d\n", name, p.Len())
+
+	// Build count of each stack.
+	var buf bytes.Buffer
+	key := func(stk []uintptr) string {
+		buf.Reset()
+		fmt.Fprintf(&buf, "@")
+		for _, pc := range stk {
+			fmt.Fprintf(&buf, " %#x", pc)
+		}
+		return buf.String()
+	}
+	m := map[string]int{}
+	n := p.Len()
+	for i := 0; i < n; i++ {
+		m[key(p.Stack(i))]++
+	}
+
+	// Print stacks, listing count on first occurrence of a unique stack.
+	for i := 0; i < n; i++ {
+		stk := p.Stack(i)
+		s := key(stk)
+		if count := m[s]; count != 0 {
+			fmt.Fprintf(w, "%d %s\n", count, s)
+			if debug > 0 {
+				printStackRecord(w, stk, false)
+			}
+			delete(m, s)
+		}
+	}
+
+	if tw != nil {
+		tw.Flush()
+	}
+	return b.Flush()
+}
+
+// printStackRecord prints the function + source line information
+// for a single stack trace.
+func printStackRecord(w io.Writer, stk []uintptr, allFrames bool) {
+	show := allFrames
+	wasPanic := false
+	for i, pc := range stk {
+		f := runtime.FuncForPC(pc)
+		if f == nil {
+			show = true
+			fmt.Fprintf(w, "#\t%#x\n", pc)
+			wasPanic = false
+		} else {
+			tracepc := pc
+			// Back up to call instruction.
+			if i > 0 && pc > f.Entry() && !wasPanic {
+				if runtime.GOARCH == "386" || runtime.GOARCH == "amd64" {
+					tracepc--
+				} else {
+					tracepc -= 4 // arm, etc
+				}
+			}
+			file, line := f.FileLine(tracepc)
+			name := f.Name()
+			// Hide runtime.goexit and any runtime functions at the beginning.
+			// This is useful mainly for allocation traces.
+			wasPanic = name == "runtime.panic"
+			if name == "runtime.goexit" || !show && strings.HasPrefix(name, "runtime.") {
+				continue
+			}
+			show = true
+			fmt.Fprintf(w, "#\t%#x\t%s+%#x\t%s:%d\n", pc, name, pc-f.Entry(), file, line)
+		}
+	}
+	if !show {
+		// We didn't print anything; do it again,
+		// and this time include runtime functions.
+		printStackRecord(w, stk, true)
+		return
+	}
+	fmt.Fprintf(w, "\n")
+}
+
+// Interface to system profiles.
+
+type byInUseBytes []runtime.MemProfileRecord
+
+func (x byInUseBytes) Len() int           { return len(x) }
+func (x byInUseBytes) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }
+func (x byInUseBytes) Less(i, j int) bool { return x[i].InUseBytes() > x[j].InUseBytes() }
+
+// WriteHeapProfile is shorthand for Lookup("heap").WriteTo(w, 0).
+// It is preserved for backwards compatibility.
+func WriteHeapProfile(w io.Writer) error {
+	return writeHeap(w, 0)
+}
+
+// countHeap returns the number of records in the heap profile.
+func countHeap() int {
+	n, _ := runtime.MemProfile(nil, true)
+	return n
+}
+
+// writeHeap writes the current runtime heap profile to w.
+func writeHeap(w io.Writer, debug int) error {
+	// Find out how many records there are (MemProfile(nil, true)),
+	// allocate that many records, and get the data.
+	// There's a race—more records might be added between
+	// the two calls—so allocate a few extra records for safety
+	// and also try again if we're very unlucky.
+	// The loop should only execute one iteration in the common case.
+	var p []runtime.MemProfileRecord
+	n, ok := runtime.MemProfile(nil, true)
+	for {
+		// Allocate room for a slightly bigger profile,
+		// in case a few more entries have been added
+		// since the call to MemProfile.
+		p = make([]runtime.MemProfileRecord, n+50)
+		n, ok = runtime.MemProfile(p, true)
+		if ok {
+			p = p[0:n]
+			break
+		}
+		// Profile grew; try again.
+	}
+
+	sort.Sort(byInUseBytes(p))
+
+	b := bufio.NewWriter(w)
+	var tw *tabwriter.Writer
+	w = b
+	if debug > 0 {
+		tw = tabwriter.NewWriter(w, 1, 8, 1, '\t', 0)
+		w = tw
+	}
+
+	var total runtime.MemProfileRecord
+	for i := range p {
+		r := &p[i]
+		total.AllocBytes += r.AllocBytes
+		total.AllocObjects += r.AllocObjects
+		total.FreeBytes += r.FreeBytes
+		total.FreeObjects += r.FreeObjects
+	}
+
+	// Technically the rate is MemProfileRate not 2*MemProfileRate,
+	// but early versions of the C++ heap profiler reported 2*MemProfileRate,
+	// so that's what pprof has come to expect.
+	fmt.Fprintf(w, "heap profile: %d: %d [%d: %d] @ heap/%d\n",
+		total.InUseObjects(), total.InUseBytes(),
+		total.AllocObjects, total.AllocBytes,
+		2*runtime.MemProfileRate)
+
+	for i := range p {
+		r := &p[i]
+		fmt.Fprintf(w, "%d: %d [%d: %d] @",
+			r.InUseObjects(), r.InUseBytes(),
+			r.AllocObjects, r.AllocBytes)
+		for _, pc := range r.Stack() {
+			fmt.Fprintf(w, " %#x", pc)
+		}
+		fmt.Fprintf(w, "\n")
+		if debug > 0 {
+			printStackRecord(w, r.Stack(), false)
+		}
+	}
+
+	// Print memstats information too.
+	// Pprof will ignore, but useful for people
+	if debug > 0 {
+		s := new(runtime.MemStats)
+		runtime.ReadMemStats(s)
+		fmt.Fprintf(w, "\n# runtime.MemStats\n")
+		fmt.Fprintf(w, "# Alloc = %d\n", s.Alloc)
+		fmt.Fprintf(w, "# TotalAlloc = %d\n", s.TotalAlloc)
+		fmt.Fprintf(w, "# Sys = %d\n", s.Sys)
+		fmt.Fprintf(w, "# Lookups = %d\n", s.Lookups)
+		fmt.Fprintf(w, "# Mallocs = %d\n", s.Mallocs)
+		fmt.Fprintf(w, "# Frees = %d\n", s.Frees)
+
+		fmt.Fprintf(w, "# HeapAlloc = %d\n", s.HeapAlloc)
+		fmt.Fprintf(w, "# HeapSys = %d\n", s.HeapSys)
+		fmt.Fprintf(w, "# HeapIdle = %d\n", s.HeapIdle)
+		fmt.Fprintf(w, "# HeapInuse = %d\n", s.HeapInuse)
+		fmt.Fprintf(w, "# HeapReleased = %d\n", s.HeapReleased)
+		fmt.Fprintf(w, "# HeapObjects = %d\n", s.HeapObjects)
+
+		fmt.Fprintf(w, "# Stack = %d / %d\n", s.StackInuse, s.StackSys)
+		fmt.Fprintf(w, "# MSpan = %d / %d\n", s.MSpanInuse, s.MSpanSys)
+		fmt.Fprintf(w, "# MCache = %d / %d\n", s.MCacheInuse, s.MCacheSys)
+		fmt.Fprintf(w, "# BuckHashSys = %d\n", s.BuckHashSys)
+
+		fmt.Fprintf(w, "# NextGC = %d\n", s.NextGC)
+		fmt.Fprintf(w, "# PauseNs = %d\n", s.PauseNs)
+		fmt.Fprintf(w, "# NumGC = %d\n", s.NumGC)
+		fmt.Fprintf(w, "# EnableGC = %v\n", s.EnableGC)
+		fmt.Fprintf(w, "# DebugGC = %v\n", s.DebugGC)
+	}
+
+	if tw != nil {
+		tw.Flush()
+	}
+	return b.Flush()
+}
+
+// countThreadCreate returns the size of the current ThreadCreateProfile.
+func countThreadCreate() int {
+	n, _ := runtime.ThreadCreateProfile(nil)
+	return n
+}
+
+// writeThreadCreate writes the current runtime ThreadCreateProfile to w.
+func writeThreadCreate(w io.Writer, debug int) error {
+	return writeRuntimeProfile(w, debug, "threadcreate", runtime.ThreadCreateProfile)
+}
+
+// countGoroutine returns the number of goroutines.
+func countGoroutine() int {
+	return runtime.NumGoroutine()
+}
+
+// writeGoroutine writes the current runtime GoroutineProfile to w.
+func writeGoroutine(w io.Writer, debug int) error {
+	if debug >= 2 {
+		return writeGoroutineStacks(w)
+	}
+	return writeRuntimeProfile(w, debug, "goroutine", runtime.GoroutineProfile)
+}
+
+func writeGoroutineStacks(w io.Writer) error {
+	// We don't know how big the buffer needs to be to collect
+	// all the goroutines.  Start with 1 MB and try a few times, doubling each time.
+	// Give up and use a truncated trace if 64 MB is not enough.
+	buf := make([]byte, 1<<20)
+	for i := 0; ; i++ {
+		n := runtime.Stack(buf, true)
+		if n < len(buf) {
+			buf = buf[:n]
+			break
+		}
+		if len(buf) >= 64<<20 {
+			// Filled 64 MB - stop there.
+			break
+		}
+		buf = make([]byte, 2*len(buf))
+	}
+	_, err := w.Write(buf)
+	return err
+}
+
+func writeRuntimeProfile(w io.Writer, debug int, name string, fetch func([]runtime.StackRecord) (int, bool)) error {
+	// Find out how many records there are (fetch(nil)),
+	// allocate that many records, and get the data.
+	// There's a race—more records might be added between
+	// the two calls—so allocate a few extra records for safety
+	// and also try again if we're very unlucky.
+	// The loop should only execute one iteration in the common case.
+	var p []runtime.StackRecord
+	n, ok := fetch(nil)
+	for {
+		// Allocate room for a slightly bigger profile,
+		// in case a few more entries have been added
+		// since the call to ThreadProfile.
+		p = make([]runtime.StackRecord, n+10)
+		n, ok = fetch(p)
+		if ok {
+			p = p[0:n]
+			break
+		}
+		// Profile grew; try again.
+	}
+
+	return printCountProfile(w, debug, name, runtimeProfile(p))
+}
+
+type runtimeProfile []runtime.StackRecord
+
+func (p runtimeProfile) Len() int              { return len(p) }
+func (p runtimeProfile) Stack(i int) []uintptr { return p[i].Stack() }
+
+var cpu struct {
+	sync.Mutex
+	profiling bool
+	done      chan bool
+}
+
+// StartCPUProfile enables CPU profiling for the current process.
+// While profiling, the profile will be buffered and written to w.
+// StartCPUProfile returns an error if profiling is already enabled.
+func StartCPUProfile(w io.Writer) error {
+	// The runtime routines allow a variable profiling rate,
+	// but in practice operating systems cannot trigger signals
+	// at more than about 500 Hz, and our processing of the
+	// signal is not cheap (mostly getting the stack trace).
+	// 100 Hz is a reasonable choice: it is frequent enough to
+	// produce useful data, rare enough not to bog down the
+	// system, and a nice round number to make it easy to
+	// convert sample counts to seconds.  Instead of requiring
+	// each client to specify the frequency, we hard code it.
+	const hz = 100
+
+	cpu.Lock()
+	defer cpu.Unlock()
+	if cpu.done == nil {
+		cpu.done = make(chan bool)
+	}
+	// Double-check.
+	if cpu.profiling {
+		return fmt.Errorf("cpu profiling already in use")
+	}
+	cpu.profiling = true
+	runtime.SetCPUProfileRate(hz)
+	go profileWriter(w)
+	return nil
+}
+
+func profileWriter(w io.Writer) {
+	for {
+		data := runtime.CPUProfile()
+		if data == nil {
+			break
+		}
+		w.Write(data)
+	}
+	cpu.done <- true
+}
+
+// StopCPUProfile stops the current CPU profile, if any.
+// StopCPUProfile only returns after all the writes for the
+// profile have completed.
+func StopCPUProfile() {
+	cpu.Lock()
+	defer cpu.Unlock()
+
+	if !cpu.profiling {
+		return
+	}
+	cpu.profiling = false
+	runtime.SetCPUProfileRate(0)
+	<-cpu.done
+}
+
+type byCycles []runtime.BlockProfileRecord
+
+func (x byCycles) Len() int           { return len(x) }
+func (x byCycles) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }
+func (x byCycles) Less(i, j int) bool { return x[i].Cycles > x[j].Cycles }
+
+// countBlock returns the number of records in the blocking profile.
+func countBlock() int {
+	n, _ := runtime.BlockProfile(nil)
+	return n
+}
+
+// writeBlock writes the current blocking profile to w.
+func writeBlock(w io.Writer, debug int) error {
+	var p []runtime.BlockProfileRecord
+	n, ok := runtime.BlockProfile(nil)
+	for {
+		p = make([]runtime.BlockProfileRecord, n+50)
+		n, ok = runtime.BlockProfile(p)
+		if ok {
+			p = p[:n]
+			break
+		}
+	}
+
+	sort.Sort(byCycles(p))
+
+	b := bufio.NewWriter(w)
+	var tw *tabwriter.Writer
+	w = b
+	if debug > 0 {
+		tw = tabwriter.NewWriter(w, 1, 8, 1, '\t', 0)
+		w = tw
+	}
+
+	fmt.Fprintf(w, "--- contention:\n")
+	fmt.Fprintf(w, "cycles/second=%v\n", runtime_cyclesPerSecond())
+	for i := range p {
+		r := &p[i]
+		fmt.Fprintf(w, "%v %v @", r.Cycles, r.Count)
+		for _, pc := range r.Stack() {
+			fmt.Fprintf(w, " %#x", pc)
+		}
+		fmt.Fprint(w, "\n")
+		if debug > 0 {
+			printStackRecord(w, r.Stack(), true)
+		}
+	}
+
+	if tw != nil {
+		tw.Flush()
+	}
+	return b.Flush()
+}
+
+func runtime_cyclesPerSecond() int64