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author | Daniil Cherednik <dan.cherednik@gmail.com> | 2022-11-24 13:14:34 +0300 |
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committer | Daniil Cherednik <dan.cherednik@gmail.com> | 2022-11-24 14:46:00 +0300 |
commit | 87f7fceed34bcafb8aaff351dd493a35c916986f (patch) | |
tree | 26809ec8f550aba8eb019e59adc3d48e51913eb2 /contrib/go/_std_1.18/src/runtime/cpuprof.go | |
parent | 11bc4015b8010ae201bf3eb33db7dba425aca35e (diff) | |
download | ydb-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.go | 218 |
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 new file mode 100644 index 0000000000..48cef46fe9 --- /dev/null +++ b/contrib/go/_std_1.18/src/runtime/cpuprof.go @@ -0,0 +1,218 @@ +// 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 +} |