// Copyright 2009 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.
// Malloc profiling.
// Patterned after tcmalloc's algorithms; shorter code.
package runtime
import (
"runtime/internal/atomic"
"unsafe"
)
// For gofrontend, use go:linkname for blockevent so that
// runtime/pprof/pprof_test can call it.
//go:linkname blockevent
// NOTE(rsc): Everything here could use cas if contention became an issue.
var proflock mutex
// All memory allocations are local and do not escape outside of the profiler.
// The profiler is forbidden from referring to garbage-collected memory.
const (
// profile types
memProfile bucketType = 1 + iota
blockProfile
mutexProfile
// a profile bucket from one of the categories above whose stack
// trace has been fixed up / pruned.
prunedProfile
// size of bucket hash table
buckHashSize = 179999
// max depth of stack to record in bucket
maxStack = 32
)
type bucketType int
// A bucket holds per-call-stack profiling information.
// The representation is a bit sleazy, inherited from C.
// This struct defines the bucket header. It is followed in
// memory by the stack words and then the actual record
// data, either a memRecord or a blockRecord.
//
// Per-call-stack profiling information.
// Lookup by hashing call stack into a linked-list hash table.
//
// No heap pointers.
//
//go:notinheap
type bucket struct {
next *bucket
allnext *bucket
typ bucketType // memBucket or blockBucket (includes mutexProfile)
hash uintptr
size uintptr
nstk uintptr
skip int
}
// A memRecord is the bucket data for a bucket of type memProfile,
// part of the memory profile.
type memRecord struct {
// The following complex 3-stage scheme of stats accumulation
// is required to obtain a consistent picture of mallocs and frees
// for some point in time.
// The problem is that mallocs come in real time, while frees
// come only after a GC during concurrent sweeping. So if we would
// naively count them, we would get a skew toward mallocs.
//
// Hence, we delay information to get consistent snapshots as
// of mark termination. Allocations count toward the next mark
// termination's snapshot, while sweep frees count toward the
// previous mark termination's snapshot:
//
// MT MT MT MT
// .·| .·| .·| .·|
// .·˙ | .·˙ | .·˙ | .·˙ |
// .·˙ | .·˙ | .·˙ | .·˙ |
// .·˙ |.·˙ |.·˙ |.·˙ |
//
// alloc → ▲ ← free
// ┠┅┅┅┅┅┅┅┅┅┅┅P
// C+2 → C+1 → C
//
// alloc → ▲ ← free
// ┠┅┅┅┅┅┅┅┅┅┅┅P
// C+2 → C+1 → C
//
// Since we can't publish a consistent snapshot until all of
// the sweep frees are accounted for, we wait until the next
// mark termination ("MT" above) to publish the previous mark
// termination's snapshot ("P" above). To do this, allocation
// and free events are accounted to *future* heap profile
// cycles ("C+n" above) and we only publish a cycle once all
// of the events from that cycle must be done. Specifically:
//
// Mallocs are accounted to cycle C+2.
// Explicit frees are accounted to cycle C+2.
// GC frees (done during sweeping) are accounted to cycle C+1.
//
// After mark termination, we increment the global heap
// profile cycle counter and accumulate the stats from cycle C
// into the active profile.
// active is the currently published profile. A profiling
// cycle can be accumulated into active once its complete.
active memRecordCycle
// future records the profile events we're counting for cycles
// that have not yet been published. This is ring buffer
// indexed by the global heap profile cycle C and stores
// cycles C, C+1, and C+2. Unlike active, these counts are
// only for a single cycle; they are not cumulative across
// cycles.
//
// We store cycle C here because there's a window between when
// C becomes the active cycle and when we've flushed it to
// active.
future [3]memRecordCycle
}
// memRecordCycle
type memRecordCycle struct {
allocs, frees uintptr
alloc_bytes, free_bytes uintptr
}
// add accumulates b into a. It does not zero b.
func (a *memRecordCycle) add(b *memRecordCycle) {
a.allocs += b.allocs
a.frees += b.frees
a.alloc_bytes += b.alloc_bytes
a.free_bytes += b.free_bytes
}
// A blockRecord is the bucket data for a bucket of type blockProfile,
// which is used in blocking and mutex profiles.
type blockRecord struct {
count float64
cycles int64
}
var (
mbuckets *bucket // memory profile buckets
bbuckets *bucket // blocking profile buckets
xbuckets *bucket // mutex profile buckets
sbuckets *bucket // pre-symbolization profile buckets (stacks fixed up)
freebuckets *bucket // freelist of unused fixed up profile buckets
buckhash *[buckHashSize]*bucket
bucketmem uintptr
mProf struct {
// All fields in mProf are protected by proflock.
// cycle is the global heap profile cycle. This wraps
// at mProfCycleWrap.
cycle uint32
// flushed indicates that future[cycle] in all buckets
// has been flushed to the active profile.
flushed bool
}
)
const mProfCycleWrap = uint32(len(memRecord{}.future)) * (2 << 24)
// payloadOffset() returns a pointer into the part of a bucket
// containing the profile payload (skips past the bucket struct itself
// and then the stack trace).
func payloadOffset(typ bucketType, nstk uintptr) uintptr {
if typ == prunedProfile {
// To allow reuse of prunedProfile buckets between different
// collections, allocate them with the max stack size (the portion
// of the stack used will vary from trace to trace).
nstk = maxStack
}
return unsafe.Sizeof(bucket{}) + uintptr(nstk)*unsafe.Sizeof(uintptr)
}
func max(x, y uintptr) uintptr {
if x > y {
return x
}
return y
}
// newBucket allocates a bucket with the given type and number of stack entries.
func newBucket(typ bucketType, nstk int, skipCount int) *bucket {
size := payloadOffset(typ, uintptr(nstk))
switch typ {
default:
throw("invalid profile bucket type")
case prunedProfile:
// stack-fixed buckets are large enough to accommodate any payload.
size += max(unsafe.Sizeof(memRecord{}), unsafe.Sizeof(blockRecord{}))
case memProfile:
size += unsafe.Sizeof(memRecord{})
case blockProfile, mutexProfile:
size += unsafe.Sizeof(blockRecord{})
}
b := (*bucket)(persistentalloc(size, 0, &memstats.buckhash_sys))
bucketmem += size
b.typ = typ
b.nstk = uintptr(nstk)
b.skip = skipCount
return b
}
// stk returns the slice in b holding the stack.
func (b *bucket) stk() []uintptr {
stk := (*[maxStack]uintptr)(add(unsafe.Pointer(b), unsafe.Sizeof(*b)))
return stk[:b.nstk:b.nstk]
}
// mp returns the memRecord associated with the memProfile bucket b.
func (b *bucket) mp() *memRecord {
if b.typ != memProfile && b.typ != prunedProfile {
throw("bad use of bucket.mp")
}
return (*memRecord)(add(unsafe.Pointer(b), payloadOffset(b.typ, b.nstk)))
}
// bp returns the blockRecord associated with the blockProfile bucket b.
func (b *bucket) bp() *blockRecord {
if b.typ != blockProfile && b.typ != mutexProfile && b.typ != prunedProfile {
throw("bad use of bucket.bp")
}
return (*blockRecord)(add(unsafe.Pointer(b), payloadOffset(b.typ, b.nstk)))
}
// Return the bucket for stk[0:nstk], allocating new bucket if needed.
func stkbucket(typ bucketType, size uintptr, skip int, stk []uintptr, alloc bool) *bucket {
if buckhash == nil {
buckhash = (*[buckHashSize]*bucket)(sysAlloc(unsafe.Sizeof(*buckhash), &memstats.buckhash_sys))
if buckhash == nil {
throw("runtime: cannot allocate memory")
}
}
// Hash stack.
var h uintptr
for _, pc := range stk {
h += pc
h += h << 10
h ^= h >> 6
}
// hash in size
h += size
h += h << 10
h ^= h >> 6
// finalize
h += h << 3
h ^= h >> 11
i := int(h % buckHashSize)
for b := buckhash[i]; b != nil; b = b.next {
if b.typ == typ && b.hash == h && b.size == size && eqslice(b.stk(), stk) {
return b
}
}
if !alloc {
return nil
}
// Create new bucket.
b := newBucket(typ, len(stk), skip)
copy(b.stk(), stk)
b.hash = h
b.size = size
b.next = buckhash[i]
buckhash[i] = b
if typ == memProfile {
b.allnext = mbuckets
mbuckets = b
} else if typ == mutexProfile {
b.allnext = xbuckets
xbuckets = b
} else if typ == prunedProfile {
b.allnext = sbuckets
sbuckets = b
} else {
b.allnext = bbuckets
bbuckets = b
}
return b
}
func eqslice(x, y []uintptr) bool {
if len(x) != len(y) {
return false
}
for i, xi := range x {
if xi != y[i] {
return false
}
}
return true
}
// mProf_NextCycle publishes the next heap profile cycle and creates a
// fresh heap profile cycle. This operation is fast and can be done
// during STW. The caller must call mProf_Flush before calling
// mProf_NextCycle again.
//
// This is called by mark termination during STW so allocations and
// frees after the world is started again count towards a new heap
// profiling cycle.
func mProf_NextCycle() {
lock(&proflock)
// We explicitly wrap mProf.cycle rather than depending on
// uint wraparound because the memRecord.future ring does not
// itself wrap at a power of two.
mProf.cycle = (mProf.cycle + 1) % mProfCycleWrap
mProf.flushed = false
unlock(&proflock)
}
// mProf_Flush flushes the events from the current heap profiling
// cycle into the active profile. After this it is safe to start a new
// heap profiling cycle with mProf_NextCycle.
//
// This is called by GC after mark termination starts the world. In
// contrast with mProf_NextCycle, this is somewhat expensive, but safe
// to do concurrently.
func mProf_Flush() {
lock(&proflock)
if !mProf.flushed {
mProf_FlushLocked()
mProf.flushed = true
}
unlock(&proflock)
}
func mProf_FlushLocked() {
c := mProf.cycle
for b := mbuckets; b != nil; b = b.allnext {
mp := b.mp()
// Flush cycle C into the published profile and clear
// it for reuse.
mpc := &mp.future[c%uint32(len(mp.future))]
mp.active.add(mpc)
*mpc = memRecordCycle{}
}
}
// mProf_PostSweep records that all sweep frees for this GC cycle have
// completed. This has the effect of publishing the heap profile
// snapshot as of the last mark termination without advancing the heap
// profile cycle.
func mProf_PostSweep() {
lock(&proflock)
// Flush cycle C+1 to the active profile so everything as of
// the last mark termination becomes visible. *Don't* advance
// the cycle, since we're still accumulating allocs in cycle
// C+2, which have to become C+1 in the next mark termination
// and so on.
c := mProf.cycle
for b := mbuckets; b != nil; b = b.allnext {
mp := b.mp()
mpc := &mp.future[(c+1)%uint32(len(mp.future))]
mp.active.add(mpc)
*mpc = memRecordCycle{}
}
unlock(&proflock)
}
// Called by malloc to record a profiled block.
func mProf_Malloc(p unsafe.Pointer, size uintptr) {
var stk [maxStack]uintptr
nstk := callersRaw(stk[:])
lock(&proflock)
skip := 1
b := stkbucket(memProfile, size, skip, stk[:nstk], true)
c := mProf.cycle
mp := b.mp()
mpc := &mp.future[(c+2)%uint32(len(mp.future))]
mpc.allocs++
mpc.alloc_bytes += size
unlock(&proflock)
// Setprofilebucket locks a bunch of other mutexes, so we call it outside of proflock.
// This reduces potential contention and chances of deadlocks.
// Since the object must be alive during call to mProf_Malloc,
// it's fine to do this non-atomically.
systemstack(func() {
setprofilebucket(p, b)
})
}
// Called when freeing a profiled block.
func mProf_Free(b *bucket, size uintptr) {
lock(&proflock)
c := mProf.cycle
mp := b.mp()
mpc := &mp.future[(c+1)%uint32(len(mp.future))]
mpc.frees++
mpc.free_bytes += size
unlock(&proflock)
}
var blockprofilerate uint64 // in CPU ticks
// SetBlockProfileRate controls the fraction of goroutine blocking events
// that are reported in the blocking profile. The profiler aims to sample
// an average of one blocking event per rate nanoseconds spent blocked.
//
// To include every blocking event in the profile, pass rate = 1.
// To turn off profiling entirely, pass rate <= 0.
func SetBlockProfileRate(rate int) {
var r int64
if rate <= 0 {
r = 0 // disable profiling
} else if rate == 1 {
r = 1 // profile everything
} else {
// convert ns to cycles, use float64 to prevent overflow during multiplication
r = int64(float64(rate) * float64(tickspersecond()) / (1000 * 1000 * 1000))
if r == 0 {
r = 1
}
}
atomic.Store64(&blockprofilerate, uint64(r))
}
func blockevent(cycles int64, skip int) {
if cycles <= 0 {
cycles = 1
}
rate := int64(atomic.Load64(&blockprofilerate))
if blocksampled(cycles, rate) {
saveblockevent(cycles, rate, skip+1, blockProfile)
}
}
// blocksampled returns true for all events where cycles >= rate. Shorter
// events have a cycles/rate random chance of returning true.
func blocksampled(cycles, rate int64) bool {
if rate <= 0 || (rate > cycles && int64(fastrand())%rate > cycles) {
return false
}
return true
}
func saveblockevent(cycles, rate int64, skip int, which bucketType) {
gp := getg()
var nstk int
var stk [maxStack]uintptr
if gp.m.curg == nil || gp.m.curg == gp {
nstk = callersRaw(stk[:])
} else {
// FIXME: This should get a traceback of gp.m.curg.
// nstk = gcallers(gp.m.curg, skip, stk[:])
nstk = callersRaw(stk[:])
}
lock(&proflock)
b := stkbucket(which, 0, skip, stk[:nstk], true)
if which == blockProfile && cycles < rate {
// Remove sampling bias, see discussion on http://golang.org/cl/299991.
b.bp().count += float64(rate) / float64(cycles)
b.bp().cycles += rate
} else {
b.bp().count++
b.bp().cycles += cycles
}
unlock(&proflock)
}
var mutexprofilerate uint64 // fraction sampled
// SetMutexProfileFraction controls the fraction of mutex contention events
// that are reported in the mutex profile. On average 1/rate events are
// reported. The previous rate is returned.
//
// To turn off profiling entirely, pass rate 0.
// To just read the current rate, pass rate < 0.
// (For n>1 the details of sampling may change.)
func SetMutexProfileFraction(rate int) int {
if rate < 0 {
return int(mutexprofilerate)
}
old := mutexprofilerate
atomic.Store64(&mutexprofilerate, uint64(rate))
return int(old)
}
//go:linkname mutexevent sync.event
func mutexevent(cycles int64, skip int) {
if cycles < 0 {
cycles = 0
}
rate := int64(atomic.Load64(&mutexprofilerate))
// TODO(pjw): measure impact of always calling fastrand vs using something
// like malloc.go:nextSample()
if rate > 0 && int64(fastrand())%rate == 0 {
saveblockevent(cycles, rate, skip+1, mutexProfile)
}
}
// Go interface to profile data.
// A StackRecord describes a single execution stack.
type StackRecord struct {
Stack0 [32]uintptr // stack trace for this record; ends at first 0 entry
}
// Stack returns the stack trace associated with the record,
// a prefix of r.Stack0.
func (r *StackRecord) Stack() []uintptr {
for i, v := range r.Stack0 {
if v == 0 {
return r.Stack0[0:i]
}
}
return r.Stack0[0:]
}
// MemProfileRate controls the fraction of memory allocations
// that are recorded and reported in the memory profile.
// The profiler aims to sample an average of
// one allocation per MemProfileRate bytes allocated.
//
// To include every allocated block in the profile, set MemProfileRate to 1.
// To turn off profiling entirely, set MemProfileRate to 0.
//
// The tools that process the memory profiles assume that the
// profile rate is constant across the lifetime of the program
// and equal to the current value. Programs that change the
// memory profiling rate should do so just once, as early as
// possible in the execution of the program (for example,
// at the beginning of main).
var MemProfileRate int = defaultMemProfileRate(512 * 1024)
// defaultMemProfileRate returns 0 if disableMemoryProfiling is set.
// It exists primarily for the godoc rendering of MemProfileRate
// above.
func defaultMemProfileRate(v int) int {
if disableMemoryProfiling {
return 0
}
return v
}
// disableMemoryProfiling is set by the linker if runtime.MemProfile
// is not used and the link type guarantees nobody else could use it
// elsewhere.
var disableMemoryProfiling bool
// A MemProfileRecord describes the live objects allocated
// by a particular call sequence (stack trace).
type MemProfileRecord struct {
AllocBytes, FreeBytes int64 // number of bytes allocated, freed
AllocObjects, FreeObjects int64 // number of objects allocated, freed
Stack0 [32]uintptr // stack trace for this record; ends at first 0 entry
}
// InUseBytes returns the number of bytes in use (AllocBytes - FreeBytes).
func (r *MemProfileRecord) InUseBytes() int64 { return r.AllocBytes - r.FreeBytes }
// InUseObjects returns the number of objects in use (AllocObjects - FreeObjects).
func (r *MemProfileRecord) InUseObjects() int64 {
return r.AllocObjects - r.FreeObjects
}
// Stack returns the stack trace associated with the record,
// a prefix of r.Stack0.
func (r *MemProfileRecord) Stack() []uintptr {
for i, v := range r.Stack0 {
if v == 0 {
return r.Stack0[0:i]
}
}
return r.Stack0[0:]
}
// reusebucket tries to pick a prunedProfile bucket off
// the freebuckets list, returning it if one is available or nil
// if the free list is empty.
func reusebucket(nstk int) *bucket {
var b *bucket
if freebuckets != nil {
b = freebuckets
freebuckets = freebuckets.allnext
b.typ = prunedProfile
b.nstk = uintptr(nstk)
mp := b.mp()
// Hack: rely on the fact that memprofile records are
// larger than blockprofile records when clearing.
*mp = memRecord{}
}
return b
}
// freebucket appends the specified prunedProfile bucket
// onto the free list, and removes references to it from the hash.
func freebucket(tofree *bucket) *bucket {
// Thread this bucket into the free list.
ret := tofree.allnext
tofree.allnext = freebuckets
freebuckets = tofree
// Clean up the hash. The hash may point directly to this bucket...
i := int(tofree.hash % buckHashSize)
if buckhash[i] == tofree {
buckhash[i] = tofree.next
} else {
// ... or when this bucket was inserted by stkbucket, it may have been
// chained off some other unrelated bucket.
for b := buckhash[i]; b != nil; b = b.next {
if b.next == tofree {
b.next = tofree.next
break
}
}
}
return ret
}
// fixupStack takes a 'raw' stack trace (stack of PCs generated by
// callersRaw) and performs pre-symbolization fixup on it, returning
// the results in 'canonStack'. For each frame we look at the
// file/func/line information, then use that info to decide whether to
// include the frame in the final symbolized stack (removing frames
// corresponding to 'morestack' routines, for example). We also expand
// frames if the PC values to which they refer correponds to inlined
// functions to allow for expanded symbolic info to be filled in
// later. Note: there is code in go-callers.c's backtrace_full callback()
// function that performs very similar fixups; these two code paths
// should be kept in sync.
func fixupStack(stk []uintptr, skip int, canonStack *[maxStack]uintptr, size uintptr) int {
var cidx int
var termTrace bool
// Increase the skip count to take into account the frames corresponding
// to runtime.callersRaw and to the C routine that it invokes.
skip += 2
sawSigtramp := false
for _, pc := range stk {
// Subtract 1 from PC to undo the 1 we added in callback in
// go-callers.c.
function, file, _, frames := funcfileline(pc-1, -1, false)
// Skip an unnamed function above sigtramp, as it is
// likely the signal handler.
if sawSigtramp {
sawSigtramp = false
if function == "" {
continue
}
}
// Skip split-stack functions (match by function name)
skipFrame := false
if hasPrefix(function, "_____morestack_") || hasPrefix(function, "__morestack_") {
skipFrame = true
}
// Skip split-stack functions (match by file)
if hasSuffix(file, "/morestack.S") {
skipFrame = true
}
// Skip thunks and recover functions and other functions
// specific to gccgo, that do not appear in the gc toolchain.
fcn := function
if hasSuffix(fcn, "..r") {
skipFrame = true
} else if function == "runtime.deferreturn" || function == "runtime.sighandler" {
skipFrame = true
} else if function == "runtime.sigtramp" || function == "runtime.sigtrampgo" {
skipFrame = true
// Also skip subsequent unnamed functions,
// which will be the signal handler itself.
sawSigtramp = true
} else {
for fcn != "" && (fcn[len(fcn)-1] >= '0' && fcn[len(fcn)-1] <= '9') {
fcn = fcn[:len(fcn)-1]
}
if hasSuffix(fcn, "..stub") || hasSuffix(fcn, "..thunk") {
skipFrame = true
}
}
if skipFrame {
continue
}
// Terminate the trace if we encounter a frame corresponding to
// runtime.main, runtime.kickoff, makecontext, etc. See the
// corresponding code in go-callers.c, callback function used
// with backtrace_full.
if function == "makecontext" {
termTrace = true
}
if hasSuffix(file, "/proc.c") && function == "runtime_mstart" {
termTrace = true
}
if hasSuffix(file, "/proc.go") &&
(function == "runtime.main" || function == "runtime.kickoff") {
termTrace = true
}
// Expand inline frames.
for i := 0; i < frames; i++ {
(*canonStack)[cidx] = pc
cidx++
if cidx >= maxStack {
termTrace = true
break
}
}
if termTrace {
break
}
}
// Apply skip count. Needs to be done after expanding inline frames.
if skip != 0 {
if skip >= cidx {
return 0
}
copy(canonStack[:cidx-skip], canonStack[skip:])
return cidx - skip
}
return cidx
}
// fixupBucket takes a raw memprofile bucket and creates a new bucket
// in which the stack trace has been fixed up (inline frames expanded,
// unwanted frames stripped out). Original bucket is left unmodified;
// a new symbolizeProfile bucket may be generated as a side effect.
// Payload information from the original bucket is incorporated into
// the new bucket.
func fixupBucket(b *bucket) {
var canonStack [maxStack]uintptr
frames := fixupStack(b.stk(), b.skip, &canonStack, b.size)
cb := stkbucket(prunedProfile, b.size, 0, canonStack[:frames], true)
switch b.typ {
default:
throw("invalid profile bucket type")
case memProfile:
rawrecord := b.mp()
cb.mp().active.add(&rawrecord.active)
case blockProfile, mutexProfile:
cb.bp().count += b.bp().count
cb.bp().cycles += b.bp().cycles
}
}
// MemProfile returns a profile of memory allocated and freed per allocation
// site.
//
// MemProfile returns n, the number of records in the current memory profile.
// If len(p) >= n, MemProfile copies the profile into p and returns n, true.
// If len(p) < n, MemProfile does not change p and returns n, false.
//
// If inuseZero is true, the profile includes allocation records
// where r.AllocBytes > 0 but r.AllocBytes == r.FreeBytes.
// These are sites where memory was allocated, but it has all
// been released back to the runtime.
//
// The returned profile may be up to two garbage collection cycles old.
// This is to avoid skewing the profile toward allocations; because
// allocations happen in real time but frees are delayed until the garbage
// collector performs sweeping, the profile only accounts for allocations
// that have had a chance to be freed by the garbage collector.
//
// Most clients should use the runtime/pprof package or
// the testing package's -test.memprofile flag instead
// of calling MemProfile directly.
func MemProfile(p []MemProfileRecord, inuseZero bool) (n int, ok bool) {
lock(&proflock)
// If we're between mProf_NextCycle and mProf_Flush, take care
// of flushing to the active profile so we only have to look
// at the active profile below.
mProf_FlushLocked()
clear := true
for b := mbuckets; b != nil; b = b.allnext {
mp := b.mp()
if inuseZero || mp.active.alloc_bytes != mp.active.free_bytes {
n++
}
if mp.active.allocs != 0 || mp.active.frees != 0 {
clear = false
}
}
if clear {
// Absolutely no data, suggesting that a garbage collection
// has not yet happened. In order to allow profiling when
// garbage collection is disabled from the beginning of execution,
// accumulate all of the cycles, and recount buckets.
n = 0
for b := mbuckets; b != nil; b = b.allnext {
mp := b.mp()
for c := range mp.future {
mp.active.add(&mp.future[c])
mp.future[c] = memRecordCycle{}
}
if inuseZero || mp.active.alloc_bytes != mp.active.free_bytes {
n++
}
}
}
if n <= len(p) {
var bnext *bucket
// Post-process raw buckets to fix up their stack traces
for b := mbuckets; b != nil; b = bnext {
bnext = b.allnext
mp := b.mp()
if inuseZero || mp.active.alloc_bytes != mp.active.free_bytes {
fixupBucket(b)
}
}
// Record pruned/fixed-up buckets
ok = true
idx := 0
for b := sbuckets; b != nil; b = b.allnext {
record(&p[idx], b)
idx++
}
n = idx
// Free up pruned buckets for use in next round
for b := sbuckets; b != nil; b = bnext {
bnext = freebucket(b)
}
sbuckets = nil
}
unlock(&proflock)
return
}
// Write b's data to r.
func record(r *MemProfileRecord, b *bucket) {
mp := b.mp()
r.AllocBytes = int64(mp.active.alloc_bytes)
r.FreeBytes = int64(mp.active.free_bytes)
r.AllocObjects = int64(mp.active.allocs)
r.FreeObjects = int64(mp.active.frees)
for i, pc := range b.stk() {
if i >= len(r.Stack0) {
break
}
r.Stack0[i] = pc
}
for i := int(b.nstk); i < len(r.Stack0); i++ {
r.Stack0[i] = 0
}
}
func iterate_memprof(fn func(*bucket, uintptr, *uintptr, uintptr, uintptr, uintptr)) {
lock(&proflock)
for b := mbuckets; b != nil; b = b.allnext {
mp := b.mp()
fn(b, b.nstk, &b.stk()[0], b.size, mp.active.allocs, mp.active.frees)
}
unlock(&proflock)
}
// BlockProfileRecord describes blocking events originated
// at a particular call sequence (stack trace).
type BlockProfileRecord struct {
Count int64
Cycles int64
StackRecord
}
func harvestBlockMutexProfile(buckets *bucket, p []BlockProfileRecord) (n int, ok bool) {
for b := buckets; b != nil; b = b.allnext {
n++
}
if n <= len(p) {
var bnext *bucket
// Post-process raw buckets to create pruned/fixed-up buckets
for b := buckets; b != nil; b = bnext {
bnext = b.allnext
fixupBucket(b)
}
// Record
ok = true
for b := sbuckets; b != nil; b = b.allnext {
bp := b.bp()
r := &p[0]
r.Count = int64(bp.count)
// Prevent callers from having to worry about division by zero errors.
// See discussion on http://golang.org/cl/299991.
if r.Count == 0 {
r.Count = 1
}
r.Cycles = bp.cycles
i := 0
var pc uintptr
for i, pc = range b.stk() {
if i >= len(r.Stack0) {
break
}
r.Stack0[i] = pc
}
for ; i < len(r.Stack0); i++ {
r.Stack0[i] = 0
}
p = p[1:]
}
// Free up pruned buckets for use in next round.
for b := sbuckets; b != nil; b = bnext {
bnext = freebucket(b)
}
sbuckets = nil
}
return
}
// BlockProfile returns n, the number of records in the current blocking profile.
// If len(p) >= n, BlockProfile copies the profile into p and returns n, true.
// If len(p) < n, BlockProfile does not change p and returns n, false.
//
// Most clients should use the runtime/pprof package or
// the testing package's -test.blockprofile flag instead
// of calling BlockProfile directly.
func BlockProfile(p []BlockProfileRecord) (n int, ok bool) {
lock(&proflock)
n, ok = harvestBlockMutexProfile(bbuckets, p)
unlock(&proflock)
return
}
// MutexProfile returns n, the number of records in the current mutex profile.
// If len(p) >= n, MutexProfile copies the profile into p and returns n, true.
// Otherwise, MutexProfile does not change p, and returns n, false.
//
// Most clients should use the runtime/pprof package
// instead of calling MutexProfile directly.
func MutexProfile(p []BlockProfileRecord) (n int, ok bool) {
lock(&proflock)
n, ok = harvestBlockMutexProfile(xbuckets, p)
unlock(&proflock)
return
}
// ThreadCreateProfile returns n, the number of records in the thread creation profile.
// If len(p) >= n, ThreadCreateProfile copies the profile into p and returns n, true.
// If len(p) < n, ThreadCreateProfile does not change p and returns n, false.
//
// Most clients should use the runtime/pprof package instead
// of calling ThreadCreateProfile directly.
func ThreadCreateProfile(p []StackRecord) (n int, ok bool) {
first := (*m)(atomic.Loadp(unsafe.Pointer(&allm)))
for mp := first; mp != nil; mp = mp.alllink {
n++
}
if n <= len(p) {
ok = true
i := 0
for mp := first; mp != nil; mp = mp.alllink {
for j := range mp.createstack {
p[i].Stack0[j] = mp.createstack[j].pc
}
i++
}
}
return
}
//go:linkname runtime_goroutineProfileWithLabels runtime_1pprof.runtime__goroutineProfileWithLabels
func runtime_goroutineProfileWithLabels(p []StackRecord, labels []unsafe.Pointer) (n int, ok bool) {
return goroutineProfileWithLabels(p, labels)
}
// labels may be nil. If labels is non-nil, it must have the same length as p.
func goroutineProfileWithLabels(p []StackRecord, labels []unsafe.Pointer) (n int, ok bool) {
if labels != nil && len(labels) != len(p) {
labels = nil
}
gp := getg()
isOK := func(gp1 *g) bool {
// Checking isSystemGoroutine here makes GoroutineProfile
// consistent with both NumGoroutine and Stack.
return gp1 != gp && readgstatus(gp1) != _Gdead && !isSystemGoroutine(gp1, false)
}
stopTheWorld("profile")
// World is stopped, no locking required.
n = 1
forEachGRace(func(gp1 *g) {
if isOK(gp1) {
n++
}
})
if n <= len(p) {
ok = true
r, lbl := p, labels
// Save current goroutine.
saveg(gp, &r[0])
r = r[1:]
// If we have a place to put our goroutine labelmap, insert it there.
if labels != nil {
lbl[0] = gp.labels
lbl = lbl[1:]
}
// Save other goroutines.
forEachGRace(func(gp1 *g) {
if isOK(gp1) {
return
}
if len(r) == 0 {
// Should be impossible, but better to return a
// truncated profile than to crash the entire process.
return
}
saveg(gp1, &r[0])
if labels != nil {
lbl[0] = gp1.labels
lbl = lbl[1:]
}
r = r[1:]
})
}
startTheWorld()
return n, ok
}
// GoroutineProfile returns n, the number of records in the active goroutine stack profile.
// If len(p) >= n, GoroutineProfile copies the profile into p and returns n, true.
// If len(p) < n, GoroutineProfile does not change p and returns n, false.
//
// Most clients should use the runtime/pprof package instead
// of calling GoroutineProfile directly.
func GoroutineProfile(p []StackRecord) (n int, ok bool) {
return goroutineProfileWithLabels(p, nil)
}
func saveg(gp *g, r *StackRecord) {
if gp == getg() {
var locbuf [32]location
n := callers(1, locbuf[:])
for i := 0; i < n; i++ {
r.Stack0[i] = locbuf[i].pc
}
if n < len(r.Stack0) {
r.Stack0[n] = 0
}
} else {
// FIXME: Not implemented.
r.Stack0[0] = 0
}
}
// Stack formats a stack trace of the calling goroutine into buf
// and returns the number of bytes written to buf.
// If all is true, Stack formats stack traces of all other goroutines
// into buf after the trace for the current goroutine.
func Stack(buf []byte, all bool) int {
if all {
stopTheWorld("stack trace")
}
n := 0
if len(buf) > 0 {
gp := getg()
// Force traceback=1 to override GOTRACEBACK setting,
// so that Stack's results are consistent.
// GOTRACEBACK is only about crash dumps.
gp.m.traceback = 1
gp.writebuf = buf[0:0:len(buf)]
goroutineheader(gp)
traceback(1)
if all {
tracebackothers(gp)
}
gp.m.traceback = 0
n = len(gp.writebuf)
gp.writebuf = nil
}
if all {
startTheWorld()
}
return n
}
// Tracing of alloc/free/gc.
var tracelock mutex
func tracealloc(p unsafe.Pointer, size uintptr, typ *_type) {
lock(&tracelock)
gp := getg()
gp.m.traceback = 2
if typ == nil {
print("tracealloc(", p, ", ", hex(size), ")\n")
} else {
print("tracealloc(", p, ", ", hex(size), ", ", typ.string(), ")\n")
}
if gp.m.curg == nil || gp == gp.m.curg {
goroutineheader(gp)
traceback(1)
} else {
goroutineheader(gp.m.curg)
// FIXME: Can't do traceback of other g.
}
print("\n")
gp.m.traceback = 0
unlock(&tracelock)
}
func tracefree(p unsafe.Pointer, size uintptr) {
lock(&tracelock)
gp := getg()
gp.m.traceback = 2
print("tracefree(", p, ", ", hex(size), ")\n")
goroutineheader(gp)
traceback(1)
print("\n")
gp.m.traceback = 0
unlock(&tracelock)
}
func tracegc() {
lock(&tracelock)
gp := getg()
gp.m.traceback = 2
print("tracegc()\n")
// running on m->g0 stack; show all non-g0 goroutines
tracebackothers(gp)
print("end tracegc\n")
print("\n")
gp.m.traceback = 0
unlock(&tracelock)
}