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https://github.com/golang/go
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7b10c49e05
This change renames the v2 execution tracer files created as part of Updates #66703 For #60773 Change-Id: I91bfdc08fec4ec68ff3a6e8b5c86f6f8bcae6e6d Reviewed-on: https://go-review.googlesource.com/c/go/+/576257 Auto-Submit: Carlos Amedee <carlos@golang.org> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Knyszek <mknyszek@google.com>
98 lines
2.4 KiB
Go
98 lines
2.4 KiB
Go
// Copyright 2023 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Trace string management.
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package runtime
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// Trace strings.
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const maxTraceStringLen = 1024
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// traceStringTable is map of string -> unique ID that also manages
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// writing strings out into the trace.
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type traceStringTable struct {
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// lock protects buf.
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lock mutex
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buf *traceBuf // string batches to write out to the trace.
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// tab is a mapping of string -> unique ID.
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tab traceMap
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}
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// put adds a string to the table, emits it, and returns a unique ID for it.
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func (t *traceStringTable) put(gen uintptr, s string) uint64 {
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// Put the string in the table.
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ss := stringStructOf(&s)
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id, added := t.tab.put(ss.str, uintptr(ss.len))
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if added {
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// Write the string to the buffer.
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systemstack(func() {
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t.writeString(gen, id, s)
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})
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}
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return id
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}
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// emit emits a string and creates an ID for it, but doesn't add it to the table. Returns the ID.
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func (t *traceStringTable) emit(gen uintptr, s string) uint64 {
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// Grab an ID and write the string to the buffer.
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id := t.tab.stealID()
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systemstack(func() {
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t.writeString(gen, id, s)
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})
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return id
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}
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// writeString writes the string to t.buf.
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//
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// Must run on the systemstack because it acquires t.lock.
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//
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//go:systemstack
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func (t *traceStringTable) writeString(gen uintptr, id uint64, s string) {
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// Truncate the string if necessary.
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if len(s) > maxTraceStringLen {
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s = s[:maxTraceStringLen]
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}
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lock(&t.lock)
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w := unsafeTraceWriter(gen, t.buf)
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// Ensure we have a place to write to.
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var flushed bool
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w, flushed = w.ensure(2 + 2*traceBytesPerNumber + len(s) /* traceEvStrings + traceEvString + ID + len + string data */)
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if flushed {
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// Annotate the batch as containing strings.
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w.byte(byte(traceEvStrings))
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}
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// Write out the string.
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w.byte(byte(traceEvString))
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w.varint(id)
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w.varint(uint64(len(s)))
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w.stringData(s)
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// Store back buf in case it was updated during ensure.
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t.buf = w.traceBuf
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unlock(&t.lock)
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}
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// reset clears the string table and flushes any buffers it has.
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//
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// Must be called only once the caller is certain nothing else will be
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// added to this table.
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func (t *traceStringTable) reset(gen uintptr) {
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if t.buf != nil {
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systemstack(func() {
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lock(&trace.lock)
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traceBufFlush(t.buf, gen)
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unlock(&trace.lock)
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})
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t.buf = nil
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}
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// Reset the table.
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t.tab.reset()
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}
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