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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
Download Patch File Download Diff File Expand all files Collapse all files
x/xnet/pcap-printer.go
+27 -1
View File
@@ -62,7 +62,33 @@ func (stack *CapturePrinter) PrintPacket(prefix string, pkt []byte) {
if err == nil {
if useTimestamps {
diff := captime.Sub(stack.origin)
fmtbuf = strconv.AppendFloat(fmtbuf, diff.Seconds(), 'f', stack.timeprec, 32)
ms := diff.Milliseconds()
fmtbuf = strconv.AppendInt(fmtbuf, ms/1000, 10)
fmtbuf = append(fmtbuf, '.')
frac := ms % 1000
if frac < 0 {
frac = -frac
}
// Pad fractional part to timeprec digits (up to 3).
switch {
case stack.timeprec >= 3:
if frac < 100 {
fmtbuf = append(fmtbuf, '0')
}
if frac < 10 {
fmtbuf = append(fmtbuf, '0')
}
fmtbuf = strconv.AppendInt(fmtbuf, frac, 10)
case stack.timeprec == 2:
frac /= 10 // truncate to centiseconds
if frac < 10 {
fmtbuf = append(fmtbuf, '0')
}
fmtbuf = strconv.AppendInt(fmtbuf, frac, 10)
case stack.timeprec == 1:
frac /= 100 // truncate to deciseconds
fmtbuf = strconv.AppendInt(fmtbuf, frac, 10)
}
fmtbuf = append(fmtbuf, ' ')
}
fmtbuf = append(fmtbuf, prefix...)
x/xnet/stack-async.go
+27
View File
@@ -2,6 +2,7 @@ package xnet
import (
"errors"
"log/slog"
"net/netip"
"sync"
"time"
@@ -11,6 +12,7 @@ import (
"github.com/soypat/lneto/dhcpv4"
"github.com/soypat/lneto/dns"
"github.com/soypat/lneto/ethernet"
"github.com/soypat/lneto/internal"
"github.com/soypat/lneto/internet"
"github.com/soypat/lneto/ntp"
"github.com/soypat/lneto/tcp"
@@ -566,3 +568,28 @@ func addr4(addr [4]byte, ok bool) netip.Addr {
}
return netip.AddrFrom4(addr)
}
// Debug prints debugging information. Very useful for users when coupled with
// the debugheaplog build tag. See [internal.LogAttrs] debugheaplog version.
//
// go build -tags=debugheaplog ./yourprogram
func (s *StackAsync) Debug(msg string) {
internal.LogAttrs(slog.Default(), slog.LevelDebug, "stackasync",
slog.String("umsg", msg),
slog.Uint64("sent", s.totalsent),
slog.Uint64("recv", s.totalrecv),
)
}
// DebugErr prints debugging and error info. Very useful for users when coupled with
// the debugheaplog build tag. See [internal.LogAttrs] debugheaplog version.
//
// go build -tags=debugheaplog ./yourprogram
func (s *StackAsync) DebugErr(msg, err string) {
internal.LogAttrs(slog.Default(), slog.LevelError, "stackasync",
slog.String("umsg", msg),
slog.String("err", err),
slog.Uint64("sent", s.totalsent),
slog.Uint64("recv", s.totalrecv),
)
}
x/xnet/xnet_test.go
+40 -33
View File
@@ -439,22 +439,22 @@ func (tst *tester) TCPExchange(expect tcpExpectExchange, stack1, stack2 *StackAs
}
srcEth := src.HardwareAddress()
dstEth := dst.HardwareAddress()
if !bytes.Equal(srcEth[:], tst.getData(pcap.ProtoEthernet, pcap.FieldClassSrc)) {
t.Errorf("mismatched ethernet src addr %x", tst.getData(pcap.ProtoEthernet, pcap.FieldClassSrc))
if !bytes.Equal(srcEth[:], tst.getData(protoEthernet, pcap.FieldClassSrc)) {
t.Errorf("mismatched ethernet src addr %x", tst.getData(protoEthernet, pcap.FieldClassSrc))
}
if !bytes.Equal(dstEth[:], tst.getData(pcap.ProtoEthernet, pcap.FieldClassDst)) {
t.Errorf("mismatched ethernet dst addr %x", tst.getData(pcap.ProtoEthernet, pcap.FieldClassDst))
if !bytes.Equal(dstEth[:], tst.getData(protoEthernet, pcap.FieldClassDst)) {
t.Errorf("mismatched ethernet dst addr %x", tst.getData(protoEthernet, pcap.FieldClassDst))
}
if tst.getInt(ethernet.TypeIPv4, pcap.FieldClassVersion) != 4 {
t.Errorf("did not get IP version=4, got=%d", tst.getInt(ethernet.TypeIPv4, pcap.FieldClassVersion))
if tst.getInt(protoIPv4, pcap.FieldClassVersion) != 4 {
t.Errorf("did not get IP version=4, got=%d", tst.getInt(protoIPv4, pcap.FieldClassVersion))
}
srcAddr := src.Addr()
dstAddr := dst.Addr()
if !bytes.Equal(srcAddr.AsSlice(), tst.getData(ethernet.TypeIPv4, pcap.FieldClassSrc)) {
t.Errorf("mismatched ip src addr %d", tst.getData(ethernet.TypeIPv4, pcap.FieldClassSrc))
if !bytes.Equal(srcAddr.AsSlice(), tst.getData(protoIPv4, pcap.FieldClassSrc)) {
t.Errorf("mismatched ip src addr %d", tst.getData(protoIPv4, pcap.FieldClassSrc))
}
if !bytes.Equal(dstAddr.AsSlice(), tst.getData(ethernet.TypeIPv4, pcap.FieldClassDst)) {
t.Errorf("mismatched ip dst addr %d", tst.getData(ethernet.TypeIPv4, pcap.FieldClassDst))
if !bytes.Equal(dstAddr.AsSlice(), tst.getData(protoIPv4, pcap.FieldClassDst)) {
t.Errorf("mismatched ip dst addr %d", tst.getData(protoIPv4, pcap.FieldClassDst))
}
tfrm := tst.getTCPFrame()
@@ -502,11 +502,11 @@ func (tst *tester) ARPExchangeOnly(querying, target *StackAsync) {
tgtIP := target.Addr()
// Validate Ethernet layer (request is broadcast)
if !bytes.Equal(qHw[:], tst.getData(pcap.ProtoEthernet, pcap.FieldClassSrc)) {
t.Errorf("request: mismatched ethernet src addr %x", tst.getData(pcap.ProtoEthernet, pcap.FieldClassSrc))
if !bytes.Equal(qHw[:], tst.getData(protoEthernet, pcap.FieldClassSrc)) {
t.Errorf("request: mismatched ethernet src addr %x", tst.getData(protoEthernet, pcap.FieldClassSrc))
}
if !bytes.Equal(broadcast[:], tst.getData(pcap.ProtoEthernet, pcap.FieldClassDst)) {
t.Errorf("request: expected broadcast ethernet dst addr, got %x", tst.getData(pcap.ProtoEthernet, pcap.FieldClassDst))
if !bytes.Equal(broadcast[:], tst.getData(protoEthernet, pcap.FieldClassDst)) {
t.Errorf("request: expected broadcast ethernet dst addr, got %x", tst.getData(protoEthernet, pcap.FieldClassDst))
}
// Validate ARP request fields
@@ -515,13 +515,13 @@ func (tst *tester) ARPExchangeOnly(querying, target *StackAsync) {
if tst.getARPOperation() != arp.OpRequest {
t.Errorf("request: expected ARP OpRequest, got %d", tst.getARPOperation())
}
if !bytes.Equal(qHw[:], tst.getFieldByClassLen(ethernet.TypeARP, pcap.FieldClassSrc, 6, 0)) {
if !bytes.Equal(qHw[:], tst.getFieldByClassLen(protoARP, pcap.FieldClassSrc, 6, 0)) {
t.Errorf("request: mismatched ARP sender HW")
}
if !bytes.Equal(qIP.AsSlice(), tst.getFieldByClassLen(ethernet.TypeARP, pcap.FieldClassSrc, 4, 0)) {
if !bytes.Equal(qIP.AsSlice(), tst.getFieldByClassLen(protoARP, pcap.FieldClassSrc, 4, 0)) {
t.Errorf("request: mismatched ARP sender proto")
}
if !bytes.Equal(tgtIP.AsSlice(), tst.getFieldByClassLen(ethernet.TypeARP, pcap.FieldClassSrc, 4, 1)) {
if !bytes.Equal(tgtIP.AsSlice(), tst.getFieldByClassLen(protoARP, pcap.FieldClassSrc, 4, 1)) {
t.Errorf("request: mismatched ARP target proto")
}
@@ -549,27 +549,27 @@ func (tst *tester) ARPExchangeOnly(querying, target *StackAsync) {
tst.buf = tst.buf[:n]
// Validate Ethernet layer (reply is unicast to querying)
if !bytes.Equal(tgtHw[:], tst.getData(pcap.ProtoEthernet, pcap.FieldClassSrc)) {
t.Errorf("reply: mismatched ethernet src addr %x", tst.getData(pcap.ProtoEthernet, pcap.FieldClassSrc))
if !bytes.Equal(tgtHw[:], tst.getData(protoEthernet, pcap.FieldClassSrc)) {
t.Errorf("reply: mismatched ethernet src addr %x", tst.getData(protoEthernet, pcap.FieldClassSrc))
}
if !bytes.Equal(qHw[:], tst.getData(pcap.ProtoEthernet, pcap.FieldClassDst)) {
t.Errorf("reply: expected unicast to querying, got %x", tst.getData(pcap.ProtoEthernet, pcap.FieldClassDst))
if !bytes.Equal(qHw[:], tst.getData(protoEthernet, pcap.FieldClassDst)) {
t.Errorf("reply: expected unicast to querying, got %x", tst.getData(protoEthernet, pcap.FieldClassDst))
}
// Validate ARP reply fields
if tst.getARPOperation() != arp.OpReply {
t.Errorf("reply: expected ARP OpReply, got %d", tst.getARPOperation())
}
if !bytes.Equal(tgtHw[:], tst.getFieldByClassLen(ethernet.TypeARP, pcap.FieldClassSrc, 6, 0)) {
if !bytes.Equal(tgtHw[:], tst.getFieldByClassLen(protoARP, pcap.FieldClassSrc, 6, 0)) {
t.Errorf("reply: mismatched ARP sender HW (should be target's MAC)")
}
if !bytes.Equal(tgtIP.AsSlice(), tst.getFieldByClassLen(ethernet.TypeARP, pcap.FieldClassSrc, 4, 0)) {
if !bytes.Equal(tgtIP.AsSlice(), tst.getFieldByClassLen(protoARP, pcap.FieldClassSrc, 4, 0)) {
t.Errorf("reply: mismatched ARP sender proto (should be target's IP)")
}
if !bytes.Equal(qHw[:], tst.getFieldByClassLen(ethernet.TypeARP, pcap.FieldClassSrc, 6, 1)) {
if !bytes.Equal(qHw[:], tst.getFieldByClassLen(protoARP, pcap.FieldClassSrc, 6, 1)) {
t.Errorf("reply: mismatched ARP target HW (should be querying's MAC)")
}
if !bytes.Equal(qIP.AsSlice(), tst.getFieldByClassLen(ethernet.TypeARP, pcap.FieldClassSrc, 4, 1)) {
if !bytes.Equal(qIP.AsSlice(), tst.getFieldByClassLen(protoARP, pcap.FieldClassSrc, 4, 1)) {
t.Errorf("reply: mismatched ARP target proto (should be querying's IP)")
}
@@ -593,7 +593,7 @@ func (tst *tester) ARPExchangeOnly(querying, target *StackAsync) {
func (tst *tester) getTCPFrame() tcp.Frame {
tst.t.Helper()
// Find the IP frame's position in the captured packet buffer.
ipFrm := getProtoFrame(tst.frmbuf, ethernet.TypeIPv4)
ipFrm := getProtoFrame(tst.frmbuf, protoIPv4)
if ipFrm == nil {
tst.t.Fatal("no IP frame in capture")
}
@@ -615,7 +615,7 @@ func (tst *tester) getTCPFrame() tcp.Frame {
return frame
}
func (tst *tester) getPayload(proto any) []byte {
func (tst *tester) getPayload(proto string) []byte {
tst.t.Helper()
i := 0
for i = 0; i < len(tst.frmbuf); i++ {
@@ -633,7 +633,7 @@ func (tst *tester) getPayload(proto any) []byte {
return tst.getData(proto, pcap.FieldClassPayload)
}
func (tst *tester) getData(proto any, field pcap.FieldClass) []byte {
func (tst *tester) getData(proto string, field pcap.FieldClass) []byte {
tst.t.Helper()
frm := getProtoFrame(tst.frmbuf, proto)
if frm == nil {
@@ -654,7 +654,7 @@ func (tst *tester) getData(proto any, field pcap.FieldClass) []byte {
return tst.buf[bitoff/8 : bitoff/8+bitlen/8]
}
func (tst *tester) getInt(proto any, field pcap.FieldClass) uint64 {
func (tst *tester) getInt(proto string, field pcap.FieldClass) uint64 {
tst.t.Helper()
frm := getProtoFrame(tst.frmbuf, proto)
if frm == nil {
@@ -671,7 +671,7 @@ func (tst *tester) getInt(proto any, field pcap.FieldClass) uint64 {
return v
}
func getProtoFrame(frms []pcap.Frame, proto any) *pcap.Frame {
func getProtoFrame(frms []pcap.Frame, proto string) *pcap.Frame {
for i := range frms {
if frms[i].Protocol == proto {
return &frms[i]
@@ -690,7 +690,7 @@ func setzero[T ~[]E, E any](s T) {
// getFieldByClassLen finds a field by protocol, class, and octet length.
// occurrence specifies which match to return (0 = first, 1 = second, etc.)
// This is needed for ARP where sender and target fields share the same class.
func (tst *tester) getFieldByClassLen(proto any, class pcap.FieldClass, octetLen, occurrence int) []byte {
func (tst *tester) getFieldByClassLen(proto string, class pcap.FieldClass, octetLen, occurrence int) []byte {
tst.t.Helper()
frm := getProtoFrame(tst.frmbuf, proto)
if frm == nil {
@@ -712,7 +712,7 @@ func (tst *tester) getFieldByClassLen(proto any, class pcap.FieldClass, octetLen
func (tst *tester) getARPOperation() arp.Operation {
tst.t.Helper()
return arp.Operation(tst.getInt(ethernet.TypeARP, pcap.FieldClassOperation))
return arp.Operation(tst.getInt(protoARP, pcap.FieldClassOperation))
}
// TestTCPConn_BufferNotClearedOnPassiveClose tests that data remains readable after
@@ -981,7 +981,7 @@ func TestStackAsync_ICMPEchoChecksum(t *testing.T) {
SequenceNumber: 4,
Payload: icmpPayload,
})
pkt[len(pkt)-1] ^= 0xFF // Corrupt ICMP payload.
pkt[len(pkt)-1] ^= 0xFF // Corrupt ICMP payload.
pkt = append(pkt, 0xDE, 0xAD, 0xBE, 0xEF) // Simulate Ethernet FCS.
err = stack.Demux(pkt, 0)
if err == nil {
@@ -989,3 +989,10 @@ func TestStackAsync_ICMPEchoChecksum(t *testing.T) {
}
}
const (
protoEthernet = "Ethernet"
protoARP = "ARP"
protoIPv4 = "IPv4"
protoTCP = "TCP"
)