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authorDaniil Cherednik <dan.cherednik@gmail.com>2022-11-24 13:14:34 +0300
committerDaniil Cherednik <dan.cherednik@gmail.com>2022-11-24 14:46:00 +0300
commit87f7fceed34bcafb8aaff351dd493a35c916986f (patch)
tree26809ec8f550aba8eb019e59adc3d48e51913eb2 /contrib/go/_std_1.18/src/runtime/cpuprof.go
parent11bc4015b8010ae201bf3eb33db7dba425aca35e (diff)
downloadydb-87f7fceed34bcafb8aaff351dd493a35c916986f.tar.gz
Ydb stable 22-4-4322.4.43
x-stable-origin-commit: 8d49d46cc834835bf3e50870516acd7376a63bcf
Diffstat (limited to 'contrib/go/_std_1.18/src/runtime/cpuprof.go')
-rw-r--r--contrib/go/_std_1.18/src/runtime/cpuprof.go218
1 files changed, 218 insertions, 0 deletions
diff --git a/contrib/go/_std_1.18/src/runtime/cpuprof.go b/contrib/go/_std_1.18/src/runtime/cpuprof.go
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+// Copyright 2011 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.
+
+// CPU profiling.
+//
+// The signal handler for the profiling clock tick adds a new stack trace
+// to a log of recent traces. The log is read by a user goroutine that
+// turns it into formatted profile data. If the reader does not keep up
+// with the log, those writes will be recorded as a count of lost records.
+// The actual profile buffer is in profbuf.go.
+
+package runtime
+
+import (
+ "internal/abi"
+ "runtime/internal/atomic"
+ "runtime/internal/sys"
+ "unsafe"
+)
+
+const maxCPUProfStack = 64
+
+type cpuProfile struct {
+ lock mutex
+ on bool // profiling is on
+ log *profBuf // profile events written here
+
+ // extra holds extra stacks accumulated in addNonGo
+ // corresponding to profiling signals arriving on
+ // non-Go-created threads. Those stacks are written
+ // to log the next time a normal Go thread gets the
+ // signal handler.
+ // Assuming the stacks are 2 words each (we don't get
+ // a full traceback from those threads), plus one word
+ // size for framing, 100 Hz profiling would generate
+ // 300 words per second.
+ // Hopefully a normal Go thread will get the profiling
+ // signal at least once every few seconds.
+ extra [1000]uintptr
+ numExtra int
+ lostExtra uint64 // count of frames lost because extra is full
+ lostAtomic uint64 // count of frames lost because of being in atomic64 on mips/arm; updated racily
+}
+
+var cpuprof cpuProfile
+
+// SetCPUProfileRate sets the CPU profiling rate to hz samples per second.
+// If hz <= 0, SetCPUProfileRate turns off profiling.
+// If the profiler is on, the rate cannot be changed without first turning it off.
+//
+// Most clients should use the runtime/pprof package or
+// the testing package's -test.cpuprofile flag instead of calling
+// SetCPUProfileRate directly.
+func SetCPUProfileRate(hz int) {
+ // Clamp hz to something reasonable.
+ if hz < 0 {
+ hz = 0
+ }
+ if hz > 1000000 {
+ hz = 1000000
+ }
+
+ lock(&cpuprof.lock)
+ if hz > 0 {
+ if cpuprof.on || cpuprof.log != nil {
+ print("runtime: cannot set cpu profile rate until previous profile has finished.\n")
+ unlock(&cpuprof.lock)
+ return
+ }
+
+ cpuprof.on = true
+ cpuprof.log = newProfBuf(1, 1<<17, 1<<14)
+ hdr := [1]uint64{uint64(hz)}
+ cpuprof.log.write(nil, nanotime(), hdr[:], nil)
+ setcpuprofilerate(int32(hz))
+ } else if cpuprof.on {
+ setcpuprofilerate(0)
+ cpuprof.on = false
+ cpuprof.addExtra()
+ cpuprof.log.close()
+ }
+ unlock(&cpuprof.lock)
+}
+
+// add adds the stack trace to the profile.
+// It is called from signal handlers and other limited environments
+// and cannot allocate memory or acquire locks that might be
+// held at the time of the signal, nor can it use substantial amounts
+// of stack.
+//go:nowritebarrierrec
+func (p *cpuProfile) add(tagPtr *unsafe.Pointer, stk []uintptr) {
+ // Simple cas-lock to coordinate with setcpuprofilerate.
+ for !atomic.Cas(&prof.signalLock, 0, 1) {
+ osyield()
+ }
+
+ if prof.hz != 0 { // implies cpuprof.log != nil
+ if p.numExtra > 0 || p.lostExtra > 0 || p.lostAtomic > 0 {
+ p.addExtra()
+ }
+ hdr := [1]uint64{1}
+ // Note: write "knows" that the argument is &gp.labels,
+ // because otherwise its write barrier behavior may not
+ // be correct. See the long comment there before
+ // changing the argument here.
+ cpuprof.log.write(tagPtr, nanotime(), hdr[:], stk)
+ }
+
+ atomic.Store(&prof.signalLock, 0)
+}
+
+// addNonGo adds the non-Go stack trace to the profile.
+// It is called from a non-Go thread, so we cannot use much stack at all,
+// nor do anything that needs a g or an m.
+// In particular, we can't call cpuprof.log.write.
+// Instead, we copy the stack into cpuprof.extra,
+// which will be drained the next time a Go thread
+// gets the signal handling event.
+//go:nosplit
+//go:nowritebarrierrec
+func (p *cpuProfile) addNonGo(stk []uintptr) {
+ // Simple cas-lock to coordinate with SetCPUProfileRate.
+ // (Other calls to add or addNonGo should be blocked out
+ // by the fact that only one SIGPROF can be handled by the
+ // process at a time. If not, this lock will serialize those too.)
+ for !atomic.Cas(&prof.signalLock, 0, 1) {
+ osyield()
+ }
+
+ if cpuprof.numExtra+1+len(stk) < len(cpuprof.extra) {
+ i := cpuprof.numExtra
+ cpuprof.extra[i] = uintptr(1 + len(stk))
+ copy(cpuprof.extra[i+1:], stk)
+ cpuprof.numExtra += 1 + len(stk)
+ } else {
+ cpuprof.lostExtra++
+ }
+
+ atomic.Store(&prof.signalLock, 0)
+}
+
+// addExtra adds the "extra" profiling events,
+// queued by addNonGo, to the profile log.
+// addExtra is called either from a signal handler on a Go thread
+// or from an ordinary goroutine; either way it can use stack
+// and has a g. The world may be stopped, though.
+func (p *cpuProfile) addExtra() {
+ // Copy accumulated non-Go profile events.
+ hdr := [1]uint64{1}
+ for i := 0; i < p.numExtra; {
+ p.log.write(nil, 0, hdr[:], p.extra[i+1:i+int(p.extra[i])])
+ i += int(p.extra[i])
+ }
+ p.numExtra = 0
+
+ // Report any lost events.
+ if p.lostExtra > 0 {
+ hdr := [1]uint64{p.lostExtra}
+ lostStk := [2]uintptr{
+ abi.FuncPCABIInternal(_LostExternalCode) + sys.PCQuantum,
+ abi.FuncPCABIInternal(_ExternalCode) + sys.PCQuantum,
+ }
+ p.log.write(nil, 0, hdr[:], lostStk[:])
+ p.lostExtra = 0
+ }
+
+ if p.lostAtomic > 0 {
+ hdr := [1]uint64{p.lostAtomic}
+ lostStk := [2]uintptr{
+ abi.FuncPCABIInternal(_LostSIGPROFDuringAtomic64) + sys.PCQuantum,
+ abi.FuncPCABIInternal(_System) + sys.PCQuantum,
+ }
+ p.log.write(nil, 0, hdr[:], lostStk[:])
+ p.lostAtomic = 0
+ }
+
+}
+
+// CPUProfile panics.
+// It formerly provided raw access to chunks of
+// a pprof-format profile generated by the runtime.
+// The details of generating that format have changed,
+// so this functionality has been removed.
+//
+// Deprecated: Use the runtime/pprof package,
+// or the handlers in the net/http/pprof package,
+// or the testing package's -test.cpuprofile flag instead.
+func CPUProfile() []byte {
+ panic("CPUProfile no longer available")
+}
+
+//go:linkname runtime_pprof_runtime_cyclesPerSecond runtime/pprof.runtime_cyclesPerSecond
+func runtime_pprof_runtime_cyclesPerSecond() int64 {
+ return tickspersecond()
+}
+
+// readProfile, provided to runtime/pprof, returns the next chunk of
+// binary CPU profiling stack trace data, blocking until data is available.
+// If profiling is turned off and all the profile data accumulated while it was
+// on has been returned, readProfile returns eof=true.
+// The caller must save the returned data and tags before calling readProfile again.
+// The returned data contains a whole number of records, and tags contains
+// exactly one entry per record.
+//
+//go:linkname runtime_pprof_readProfile runtime/pprof.readProfile
+func runtime_pprof_readProfile() ([]uint64, []unsafe.Pointer, bool) {
+ lock(&cpuprof.lock)
+ log := cpuprof.log
+ unlock(&cpuprof.lock)
+ data, tags, eof := log.read(profBufBlocking)
+ if len(data) == 0 && eof {
+ lock(&cpuprof.lock)
+ cpuprof.log = nil
+ unlock(&cpuprof.lock)
+ }
+ return data, tags, eof
+}