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Reduce heap allocs 2 (#46)

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* reduce heap allocations in tcp logging; omit use of AppendFloat which allocates a metric sh*tton

* debugheaplog: better heap statistic logging

* heap: use string for pcap.Frame.Protocol

* add potential to eliminate Flags.String heap alloc, remove incorrect HEAP comments

* add StackAsync.DebugErr and httpraw.SetBytes

* many heap alloc reductions and replacement of bytes.Equal with internal.BytesEqual
This commit is contained in:
Pat Whittingslow
2026-02-28 19:20:46 +01:00
committed by GitHub
parent eab43c4653
commit 989bb6a0b9
22 changed files with 511 additions and 163 deletions
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internet/pcap/format.go
+18 -22
View File
@@ -4,7 +4,6 @@ import (
"encoding/binary"
"encoding/hex"
"errors"
"fmt"
"math"
"net/netip"
"slices"
@@ -12,8 +11,8 @@ import (
"strings"
"sync"
_ "time"
"unsafe"
"github.com/soypat/lneto"
"github.com/soypat/lneto/ethernet"
"github.com/soypat/lneto/ntp"
"github.com/soypat/lneto/tcp"
@@ -38,6 +37,7 @@ type Formatter struct {
// FormatFrames appends the formatted frame data to the destination buffer according the Formatter state.
// Is equivalent to [Formatter.FormatFrame] called on each Frame with the FrameSep inserted between frames.
func (f *Formatter) FormatFrames(dst []byte, frms []Frame, pkt []byte) (_ []byte, err error) {
debuglog("pcap:fmt:start")
sep := f.frameSep()
for ifrm := range frms {
if ifrm != 0 {
@@ -48,14 +48,16 @@ func (f *Formatter) FormatFrames(dst []byte, frms []Frame, pkt []byte) (_ []byte
return dst, err
}
}
debuglog("pcap:fmt:done")
return dst, nil
}
// FormatFrame formats a single frame's protocol, fields, and errors into dst.
func (f *Formatter) FormatFrame(dst []byte, frm Frame, pkt []byte) (_ []byte, err error) {
debuglog("pcap:fmtframe:start")
sep := f.fieldSep()
bitlen := frm.LenBits()
dst = appendProtocol(dst, frm.Protocol)
dst = append(dst, frm.Protocol...)
if bitlen%8 == 0 {
dst = append(dst, " len="...)
dst = strconv.AppendInt(dst, int64(bitlen/8), 10)
@@ -70,7 +72,7 @@ func (f *Formatter) FormatFrame(dst []byte, frm Frame, pkt []byte) (_ []byte, er
continue
}
dst = append(dst, sep...)
if field.Class == FieldClassFlags && frm.Protocol == lneto.IPProtoTCP {
if field.Class == FieldClassFlags && frm.Protocol == "TCP" {
// TCP flags pretty print special case.
dst = append(dst, "flags="...)
v, err := f.fieldAsUint(pkt, frm.PacketBitOffset+field.FrameBitOffset, field.BitLength, field.Flags.IsRightAligned())
@@ -95,6 +97,7 @@ func (f *Formatter) FormatFrame(dst []byte, frm Frame, pkt []byte) (_ []byte, er
}
dst = append(dst, ')')
}
debuglog("pcap:fmtframe:done")
return dst, nil
}
@@ -135,6 +138,9 @@ func (f *Formatter) formatField(dst []byte, pktStartOff int, field FrameField, p
if hasSpaces {
dst = append(dst, ')')
}
if field.BitLength == 0 {
return dst, nil
}
dst = append(dst, '=')
f.mubuf.Lock()
defer f.mubuf.Unlock()
@@ -142,6 +148,7 @@ func (f *Formatter) formatField(dst []byte, pktStartOff int, field FrameField, p
if err != nil {
return dst, err
}
debuglog("pcap:fmtfield:append-done")
fieldBitStart := pktStartOff + field.FrameBitOffset
switch field.Class {
default:
@@ -151,6 +158,7 @@ func (f *Formatter) formatField(dst []byte, pktStartOff int, field FrameField, p
dst = append(dst, "0x"...)
dst = hex.AppendEncode(dst, f.buf)
case FieldClassTimestamp:
debuglog("pcap:fmtfield:timestamp")
// inspired by [time.RFC3339]
const littlerfc3339 = "2006-01-02T15:04:05.9999"
if len(f.buf) != 8 {
@@ -158,8 +166,13 @@ func (f *Formatter) formatField(dst []byte, pktStartOff int, field FrameField, p
}
ts := ntp.TimestampFromUint64(binary.BigEndian.Uint64(f.buf))
dst = ts.Time().AppendFormat(dst, littlerfc3339)
debuglog("pcap:fmtfield:timestamp-done")
case FieldClassText:
dst = strconv.AppendQuote(dst, string(f.buf))
debuglog("pcap:fmtfield:text")
if len(f.buf) > 0 {
dst = strconv.AppendQuote(dst, unsafe.String(&f.buf[0], len(f.buf)))
}
debuglog("pcap:fmtfield:text-done")
case FieldClassDst, FieldClassSrc, FieldClassSize, FieldClassAddress, FieldClassOperation:
// IP, MAC addresses and ports.
if field.BitLength <= 16 {
@@ -219,20 +232,3 @@ func (f *Formatter) fieldAsUint(pkt []byte, fieldBitStart, bitlen int, rightAlig
}
return binary.BigEndian.Uint64(f.uintBuf[:]), nil
}
// appendProtocol appends the string representation of a Frame.Protocol value
// to dst without going through fmt.Appendf reflect machinery.
func appendProtocol(dst []byte, p any) []byte {
switch p := p.(type) {
case proto:
return append(dst, string(p)...)
case string:
return append(dst, p...)
case ethernet.Type:
return append(dst, p.String()...)
case lneto.IPProto:
return append(dst, p.String()...)
default:
return fmt.Appendf(dst, "%v", p)
}
}