go/src/runtime/tracebuf.go

const traceBytesPerNumber …

type traceWriter …

// writer returns an a traceWriter that writes into the current M's stream.
//
// Once this is called, the caller must guard against stack growth until
// end is called on it. Therefore, it's highly recommended to use this
// API in a "fluent" style, for example tl.writer().event(...).end().
// Better yet, callers just looking to write events should use eventWriter
// when possible, which is a much safer wrapper around this function.
//
// nosplit to allow for safe reentrant tracing from stack growth paths.
//
//go:nosplit
func (tl traceLocker) writer() traceWriter { … }

// unsafeTraceWriter produces a traceWriter that doesn't lock the trace.
//
// It should only be used in contexts where either:
// - Another traceLocker is held.
// - trace.gen is prevented from advancing.
//
// This does not have the same stack growth restrictions as traceLocker.writer.
//
// buf may be nil.
func unsafeTraceWriter(gen uintptr, buf *traceBuf) traceWriter { … }

// event writes out the bytes of an event into the event stream.
//
// nosplit because it's part of writing an event for an M, which must not
// have any stack growth.
//
//go:nosplit
func (w traceWriter) event(ev traceEv, args ...traceArg) traceWriter { … }

// end writes the buffer back into the m.
//
// nosplit because it's part of writing an event for an M, which must not
// have any stack growth.
//
//go:nosplit
func (w traceWriter) end() { … }

// ensure makes sure that at least maxSize bytes are available to write.
//
// Returns whether the buffer was flushed.
//
// nosplit because it's part of writing an event for an M, which must not
// have any stack growth.
//
//go:nosplit
func (w traceWriter) ensure(maxSize int) (traceWriter, bool) { … }

// flush puts w.traceBuf on the queue of full buffers.
//
// nosplit because it's part of writing an event for an M, which must not
// have any stack growth.
//
//go:nosplit
func (w traceWriter) flush() traceWriter { … }

// refill puts w.traceBuf on the queue of full buffers and refresh's w's buffer.
func (w traceWriter) refill() traceWriter { … }

type traceBufQueue …

// push queues buf into queue of buffers.
func (q *traceBufQueue) push(buf *traceBuf) { … }

// pop dequeues from the queue of buffers.
func (q *traceBufQueue) pop() *traceBuf { … }

func (q *traceBufQueue) empty() bool { … }

type traceBufHeader …

type traceBuf …

// byte appends v to buf.
//
// nosplit because it's part of writing an event for an M, which must not
// have any stack growth.
//
//go:nosplit
func (buf *traceBuf) byte(v byte) { … }

// varint appends v to buf in little-endian-base-128 encoding.
//
// nosplit because it's part of writing an event for an M, which must not
// have any stack growth.
//
//go:nosplit
func (buf *traceBuf) varint(v uint64) { … }

// varintReserve reserves enough space in buf to hold any varint.
//
// Space reserved this way can be filled in with the varintAt method.
//
// nosplit because it's part of writing an event for an M, which must not
// have any stack growth.
//
//go:nosplit
func (buf *traceBuf) varintReserve() int { … }

// stringData appends s's data directly to buf.
//
// nosplit because it's part of writing an event for an M, which must not
// have any stack growth.
//
//go:nosplit
func (buf *traceBuf) stringData(s string) { … }

// nosplit because it's part of writing an event for an M, which must not
// have any stack growth.
//
//go:nosplit
func (buf *traceBuf) available(size int) bool { … }

// varintAt writes varint v at byte position pos in buf. This always
// consumes traceBytesPerNumber bytes. This is intended for when the caller
// needs to reserve space for a varint but can't populate it until later.
// Use varintReserve to reserve this space.
//
// nosplit because it's part of writing an event for an M, which must not
// have any stack growth.
//
//go:nosplit
func (buf *traceBuf) varintAt(pos int, v uint64) { … }

// traceBufFlush flushes a trace buffer.
//
// Must run on the system stack because trace.lock must be held.
//
//go:systemstack
func traceBufFlush(buf *traceBuf, gen uintptr) { … }