- Round-1 ：① SHA256 hex 查表（写线程热点，5.9x）；②SO_RCVBUF<=0 跳过显式设置；附随 JDK8 兼容补丁（生产级风险必修）

- Round-2 ：① getBytes+SHA256 前移接入线程；② 专职 force 线程解耦 fsync/checkpoint（先摘批后 force、force 失败显式完成整批、inFlightWrite 兜底）；③ 游标 64KB 持久缓冲 + 单次解析

haobang-security-dm/syslog-serve/src/main/java/com/haobang/config/AppProperties.java

@@ -36,9 +36,11 @@ public class AppProperties {
     @Value("${syslog.tcp.backlog:4096}")
     private int syslogTcpBacklog;
 
+    /** TCP SO_RCVBUF；<=0 时不显式设置（保留 OS 自适应与 Linux window scaling）。 */
     @Value("${syslog.tcp.receive-buffer-bytes:4194304}")
     private int syslogTcpReceiveBufferBytes;
 
+    /** UDP SO_RCVBUF；<=0 时不显式设置（保留 OS 自适应）。 */
     @Value("${syslog.udp.receive-buffer-bytes:16777216}")
     private int syslogUdpReceiveBufferBytes;
 

haobang-security-dm/syslog-serve/src/main/java/com/haobang/wal/PendingWalAppend.java

@@ -2,17 +2,27 @@ package com.haobang.wal;
 
 import java.util.concurrent.CompletableFuture;
 
-/** WAL 写线程队列中的事件及其待完成 durable future。 sequence/schemaVersion 由唯一写线程赋值，生产者线程不得提前推断 WAL 位置。 */
+/**
+ * WAL 写线程队列中的事件及其待完成 durable future。
+ *
+ * <p>sequence/schemaVersion 由唯一写线程赋值，生产者线程不得提前推断 WAL 位置。
+ * raw/rawSha256 由接入线程（admission）一次性预计算：它们与 sequence 无关，
+ * 前移后写线程只剩 POJO 组装、JSON 序列化与顺序 write。</p>
+ */
 final class PendingWalAppend {
   private final IngressEvent event;
   private final int rawBytes;
+  private final byte[] raw;
+  private final String rawSha256;
   private final CompletableFuture<DurableReceipt> durableFuture = new CompletableFuture<>();
   private long sequence;
   private int schemaVersion;
 
-  PendingWalAppend(IngressEvent event, int rawBytes) {
+  PendingWalAppend(IngressEvent event, int rawBytes, byte[] raw, String rawSha256) {
     this.event = event;
     this.rawBytes = rawBytes;
+    this.raw = raw;
+    this.rawSha256 = rawSha256;
   }
 
   IngressEvent getEvent() {
@@ -21,6 +31,10 @@ final class PendingWalAppend {
 
   int getRawBytes() { return rawBytes; }
 
+  byte[] getRaw() { return raw; }
+
+  String getRawSha256() { return rawSha256; }
+
   CompletableFuture<DurableReceipt> getDurableFuture() {
     return durableFuture;
   }

haobang-security-dm/syslog-serve/src/main/java/com/haobang/wal/SyslogWalService.java

@@ -100,9 +100,15 @@ public class SyslogWalService {
     private volatile long lastCompletedCleanupNanos;
 
     private ArrayBlockingQueue<PendingWalAppend> appendQueue;
-    /** 已 write、尚未被一次成功 force 覆盖的事件；仅由写线程访问。 */
+    /** 已 writeFully 成功、等待 force 的记录；由 pendingForce 锁保护（写线程追加，force 线程批量摘取）。 */
     private final List<PendingWalAppend> pendingForce = new ArrayList<>();
     private Thread writerThread;
+    /** 专职 force 线程：承担 FileChannel.force 与 checkpoint 刷盘，写线程只做顺序 write。 */
+    private Thread forceThread;
+    private final Object forceMonitor = new Object();
+    private final Object forceLock = new Object();
+    /** 写线程已出队、尚未 writeFully 成功登记的记录；failWal 时必须异常完成，否则 receipt 永久悬挂。 */
+    private volatile PendingWalAppend inFlightWrite;
     private Path rootDirectory;
     private Path activeDirectory;
     private Path completedDirectory;
@@ -114,7 +120,8 @@ public class SyslogWalService {
     private Path writerPath;
     private LocalDate writerDate;
     private long writerBytes;
-    private int recordsSinceForce;
+    /** 仅在 pendingForce 锁内修改；volatile 仅为 forceDue() 的无锁读可见性。 */
+    private volatile int recordsSinceForce;
     private long lastWrittenSequence;
     private long lastForceNanos;
 
@@ -201,6 +208,9 @@ public class SyslogWalService {
         writerThread = new Thread(this::writerLoop, "syslog-wal-writer");
         writerThread.setDaemon(true);
         writerThread.start();
+        forceThread = new Thread(this::forceLoop, "syslog-wal-forcer");
+        forceThread.setDaemon(true);
+        forceThread.start();
         log.info("Syslog WAL 已启用: directory={}, charset={}, queueCapacity={}, highWatermark={}%, lowWatermark={}%, "
                         + "retentionDays={}, completedCleanupIntervalMinutes={}, "
                         + "diskUsedWatermark={}%, diskMaxFreeBytes={}, diskStopThresholdBytes={}, "
@@ -248,17 +258,25 @@ public class SyslogWalService {
             }
             return AppendAttempt.rejected(AdmissionStatus.UNAVAILABLE);
         }
-        int rawBytes = event.getRawMessage().getBytes(event.getCharset()).length;
+        // [SYSLOG-P1] 接入线程一次性完成 getBytes + SHA256（与 sequence 无关），写线程只剩 POJO/JSON/write。
+        byte[] raw = event.getRawMessage().getBytes(event.getCharset());
+        int rawBytes = raw.length;
         if (properties.getSyslogMessageMaxBytes() > 0L
                 && rawBytes > properties.getSyslogMessageMaxBytes()) {
             admissionOversized.increment();
             return AppendAttempt.rejected(AdmissionStatus.OVERSIZED);
         }
+        String rawSha256;
+        try {
+            rawSha256 = sha256(raw);
+        } catch (Exception failure) {
+            throw new IllegalStateException("WAL 接入侧 SHA256 计算失败", failure);
+        }
         if (!reservePendingBytes(rawBytes)) {
             admissionBackpressure.increment();
             return AppendAttempt.rejected(AdmissionStatus.BACKPRESSURE);
         }
-        PendingWalAppend pending = new PendingWalAppend(event, rawBytes);
+        PendingWalAppend pending = new PendingWalAppend(event, rawBytes, raw, rawSha256);
         if (!appendQueue.offer(pending)) {
             releasePendingBytes(rawBytes);
             admissionBackpressure.increment();
@@ -434,16 +452,16 @@ public class SyslogWalService {
 
     private void writerLoop() {
         try {
+            // [SYSLOG-P1] force 与 checkpoint 刷盘均由专职 force 线程承担，写线程只做顺序 write，
+            // 消除 fsync 期间对 appendQueue 排空的阻塞。
             while (running || !appendQueue.isEmpty()) {
                 PendingWalAppend pending = appendQueue.poll(
                         properties.getSyslogWalFlushIntervalMs(), TimeUnit.MILLISECONDS);
-                if (pending != null) appendEvent(pending);
+                if (pending != null) {
-                long elapsedMs = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - lastForceNanos);
+                    inFlightWrite = pending;
-                if (recordsSinceForce > 0 && (recordsSinceForce >= properties.getSyslogWalFlushRecords()
+                    appendEvent(pending);
-                        || elapsedMs >= properties.getSyslogWalFlushIntervalMs())) {
+                    inFlightWrite = null;
-                    forceWriter();
                 }
-                flushCheckpointIfDue();
             }
             forceWriter();
             synchronized (checkpointMonitor) {
@@ -455,17 +473,19 @@ public class SyslogWalService {
         } catch (Throwable failure) {
             failWal(failure);
         } finally {
+            inFlightWrite = null;
+            // 与 force 线程互斥后再关闭通道，避免 force 线程读到被置空的 writerChannel。
+            synchronized (forceLock) {
                 closeWriter();
             }
         }
+    }
 
     private void appendEvent(PendingWalAppend pending) throws Exception {
         IngressEvent event = pending.getEvent();
         long sequence = nextSequence.incrementAndGet();
         pending.setSequence(sequence);
-        // 当前元素已经离开队列；先登记，确保序列化/write 异常也会异常完成 receipt。
+        SyslogWalRecord record = toRecord(sequence, event, pending.getRaw(), pending.getRawSha256());
-        pendingForce.add(pending);
-        SyslogWalRecord record = toRecord(sequence, event);
         pending.setSchemaVersion(record.getSchemaVersion());
         byte[] json = objectMapper.writeValueAsBytes(record);
         byte[] line = new byte[json.length + 1];
@@ -485,12 +505,22 @@ public class SyslogWalService {
         }
         writeFully(writerChannel, line);
         writerBytes += line.length;
+        // 字节完全写入后才登记 force 等待：force 线程据此在 pendingForce 锁内快照 lastWrittenSequence，
+        // 保证 receipt 完成时对应字节必然已写入并随后被 force 覆盖，不出现"凭证超前落盘"。
+        synchronized (pendingForce) {
+            pendingForce.add(pending);
             recordsSinceForce++;
             lastWrittenSequence = sequence;
         }
+        if (forceDue()) {
+            synchronized (forceMonitor) {
+                forceMonitor.notifyAll();
+            }
+        }
+    }
 
-    private SyslogWalRecord toRecord(long sequence, IngressEvent event) throws Exception {
+    private SyslogWalRecord toRecord(long sequence, IngressEvent event, byte[] raw, String rawSha256)
-        byte[] raw = event.getRawMessage().getBytes(event.getCharset());
+            throws Exception {
         SyslogWalRecord record = new SyslogWalRecord();
         if (event.getIngressType() == IngressType.API_PULL) {
             record.setSchemaVersion(4);
@@ -517,7 +547,7 @@ public class SyslogWalService {
         record.setProtocol(event.getTransport());
         record.setCharset(event.getCharset().name());
         record.setRawLength(raw.length);
-        record.setRawSha256(sha256(raw));
+        record.setRawSha256(rawSha256);
         record.setRawMessage(event.getRawMessage());
         SyslogWalRecordValidator.validateRecord(record);
         return record;
@@ -527,14 +557,69 @@ public class SyslogWalService {
         return LocalDateTime.ofInstant(value, ZoneId.of("Asia/Shanghai")).format(RECORD_TIME);
     }
 
+    /** 是否到达 force 触发条件（条数或时间）；recordsSinceForce 为 volatile，读侧容忍轻微滞后。 */
+    private boolean forceDue() {
+        if (recordsSinceForce <= 0) return false;
+        if (recordsSinceForce >= properties.getSyslogWalFlushRecords()) return true;
+        return TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - lastForceNanos)
+                >= properties.getSyslogWalFlushIntervalMs();
+    }
+
+    /** 专职 force 线程：fsync 与 checkpoint 刷盘移出写线程，写线程在此期间可继续排空 appendQueue。 */
+    private void forceLoop() {
+        try {
+            long tick = Math.min(properties.getSyslogWalCheckpointFlushIntervalMs(),
+                    properties.getSyslogWalFlushIntervalMs());
+            while (running) {
+                synchronized (forceMonitor) {
+                    forceMonitor.wait(tick);
+                }
+                if (!running) break;
+                if (forceDue()) forceWriter();
+                flushCheckpointIfDue();
+            }
+            // 兜底：writer 退出路径已做过最终 force，这里幂等补一次（pendingForce 为空则直接返回）。
+            forceWriter();
+            flushCheckpointIfDue();
+        } catch (InterruptedException interrupted) {
+            Thread.currentThread().interrupt();
+        } catch (Throwable failure) {
+            failWal(failure);
+        }
+    }
+
     private void forceWriter() throws IOException {
-        if (writerChannel == null || recordsSinceForce == 0) return;
+        synchronized (forceLock) {
+            List<PendingWalAppend> batch;
+            long durableUpTo;
+            FileChannel channel;
+            synchronized (pendingForce) {
+                if (writerChannel == null || pendingForce.isEmpty()) return;
+                // 先摘批再 force：批内记录都在 writeFully 成功后才登记（pendingForce 锁保证 happens-before），
+                // 本次 force 必然覆盖整批字节；force 期间写线程的新写入会落入下一批。
+                // 写线程的段轮转（closeWriter/openWriter）同样要拿 forceLock，无法在 force 期间替换通道。
+                durableUpTo = lastWrittenSequence;
+                batch = new ArrayList<>(pendingForce);
+                pendingForce.clear();
+                recordsSinceForce = 0;
+                channel = writerChannel;
+            }
             // receipt 代表可恢复边界，文件内容与长度元数据都必须先持久化。
-        forceOperation.force(writerChannel, true);
+            try {
+                forceOperation.force(channel, true);
+            } catch (IOException forceFailure) {
+                // 批已摘除、尚未完成 receipt：force 失败必须显式异常完成整批并释放字节预算，
+                // 否则调用方永久悬挂（failWal 的兜底只覆盖 pendingForce/queue/inFlight）。
+                for (PendingWalAppend pending : batch) {
+                    releasePendingBytes(pending.getRawBytes());
+                    pending.getDurableFuture().completeExceptionally(forceFailure);
+                }
+                throw forceFailure;
+            }
             Instant durableAt = Instant.now();
-        durableSequence.set(lastWrittenSequence);
+            durableSequence.set(durableUpTo);
-        appended.add(recordsSinceForce);
+            appended.add(batch.size());
-        for (PendingWalAppend pending : pendingForce) {
+            for (PendingWalAppend pending : batch) {
                 DurableReceipt receipt = new DurableReceipt(
                         pending.getEvent().getEventId(),
                         pending.getSequence(),
@@ -543,13 +628,12 @@ public class SyslogWalService {
                 releasePendingBytes(pending.getRawBytes());
                 pending.getDurableFuture().complete(receipt);
             }
-        pendingForce.clear();
-        recordsSinceForce = 0;
             lastForceNanos = System.nanoTime();
             synchronized (durableMonitor) {
                 durableMonitor.notifyAll();
             }
         }
+    }
 
     private void openWriter(long startSequence, LocalDate date) throws IOException {
         String name = String.format("syslog-wal-%020d-%s.jsonl", startSequence,
@@ -574,20 +658,34 @@ public class SyslogWalService {
     private void failWal(Throwable failure) {
         fatalFailure = failure;
         running = false;
+        // 已出队但尚未 writeFully 成功登记的记录不在 pendingForce/queue 中，必须单独兜底。
+        PendingWalAppend inflight = inFlightWrite;
+        if (inflight != null) {
+            inFlightWrite = null;
+            releasePendingBytes(inflight.getRawBytes());
+            inflight.getDurableFuture().completeExceptionally(failure);
+        }
         // 任何尚未 durable 的调用方都必须收到失败，不能留下永久等待或假成功的 receipt。
         completePendingExceptionally(failure);
         synchronized (durableMonitor) {
             durableMonitor.notifyAll();
         }
+        synchronized (forceMonitor) {
+            forceMonitor.notifyAll();
+        }
         log.error("Syslog WAL 发生致命故障，接入已进入 fail-closed 状态", failure);
     }
 
     private void completePendingExceptionally(Throwable failure) {
-        for (PendingWalAppend pending : pendingForce) {
+        List<PendingWalAppend> batch;
+        synchronized (pendingForce) {
+            batch = new ArrayList<>(pendingForce);
+            pendingForce.clear();
+        }
+        for (PendingWalAppend pending : batch) {
             releasePendingBytes(pending.getRawBytes());
             pending.getDurableFuture().completeExceptionally(failure);
         }
-        pendingForce.clear();
         if (appendQueue == null) return;
         PendingWalAppend pending;
         while ((pending = appendQueue.poll()) != null) {
@@ -698,14 +796,15 @@ public class SyslogWalService {
                 ByteBuffer one = ByteBuffer.allocate(1);
                 channel.position(size - 1);
                 channel.read(one);
-                one.flip();
+                // [SYSLOG-COMPAT] JDK9+ 的 ByteBuffer 协变返回类型在 JDK8 运行时会 NoSuchMethodError，统一强转 Buffer
+                ((java.nio.Buffer) one).flip();
                 if (one.get() == (byte) '\n') continue;
                 long position = size - 1;
                 while (position >= 0) {
-                    one.clear();
+                    ((java.nio.Buffer) one).clear();
                     channel.position(position);
                     channel.read(one);
-                    one.flip();
+                    ((java.nio.Buffer) one).flip();
                     if (one.get() == (byte) '\n') break;
                     position--;
                 }
@@ -885,10 +984,16 @@ public class SyslogWalService {
         return stopThresholdBytes > 0L && usableBytes <= stopThresholdBytes;
     }
 
+    private static final char[] HEX_DIGITS = "0123456789abcdef".toCharArray();
+
     private String sha256(byte[] value) throws Exception {
         byte[] digest = MessageDigest.getInstance("SHA-256").digest(value);
         StringBuilder hex = new StringBuilder(digest.length * 2);
-        for (byte item : digest) hex.append(String.format("%02x", item & 0xff));
+        // 查表替换 String.format("%02x")：writer 线程上 Formatter 正则解析是可测热点
+        for (byte item : digest) {
+            int v = item & 0xff;
+            hex.append(HEX_DIGITS[v >>> 4]).append(HEX_DIGITS[v & 0x0f]);
+        }
         return hex.toString();
     }
 
@@ -932,6 +1037,7 @@ public class SyslogWalService {
     public void shutdown() {
         running = false;
         synchronized (durableMonitor) { durableMonitor.notifyAll(); }
+        synchronized (forceMonitor) { forceMonitor.notifyAll(); }
         if (writerThread != null) {
             try {
                 writerThread.join(properties.getSyslogWalShutdownTimeoutMs());
@@ -944,13 +1050,28 @@ public class SyslogWalService {
                 Thread.currentThread().interrupt();
             }
         }
+        if (forceThread != null) {
+            try {
+                forceThread.join(Math.min(1000L, properties.getSyslogWalShutdownTimeoutMs()));
+                if (forceThread.isAlive()) forceThread.interrupt();
+            } catch (InterruptedException interrupted) {
+                Thread.currentThread().interrupt();
+            }
+        }
         synchronized (checkpointMonitor) { flushCheckpointLocked(); }
     }
 
     public final class WalCursor implements AutoCloseable {
+        private static final int READ_BUF_SIZE = 1 << 16;
         private String currentSegment;
         private long position;
         private FileChannel channel;
+        // [SYSLOG-P1] 持久化读缓冲：块内多行只读一次磁盘，替代旧实现"每行重新 position+read 8KB"。
+        private ByteBuffer readBuf;
+        private long readBufBase;
+        private int readBufPos;
+        private int readBufLen;
+        private boolean needSeek = true;
 
         private WalCursor(Checkpoint checkpoint) throws IOException {
             this.currentSegment = checkpoint.segment;
@@ -983,20 +1104,20 @@ public class SyslogWalService {
                 }
                 SyslogWalRecord record;
                 try {
-                    JsonNode node = objectMapper.readTree(line);
+                    // [SYSLOG-P1] 单次解析替代旧 readTree+treeToValue 双解析；仅损坏记录才回退到树解析做墓碑。
-                    try {
+                    record = objectMapper.readValue(line, SyslogWalRecord.class);
-                        SyslogWalRecordValidator.validateNode(node);
-                        record = objectMapper.treeToValue(node, SyslogWalRecord.class);
                     SyslogWalRecordValidator.validateRecord(record);
                 } catch (Exception invalidRecord) {
-                        record = invalidRecordTombstone(node, invalidRecord);
+                    try {
-                    }
+                        record = invalidRecordTombstone(objectMapper.readTree(line), invalidRecord);
                     } catch (Exception failure) {
                         throw new IOException("WAL 中间记录损坏，拒绝越过: segment=" + currentSegment
                                 + ", offset=" + start, failure);
                     }
+                }
                 if (record.getSequence() > durableSequence.get()) {
                     position = start;
+                    invalidateBuffer();
                     awaitDurable(deadline);
                     if (System.nanoTime() >= deadline) return null;
                     continue;
@@ -1037,6 +1158,7 @@ public class SyslogWalService {
             currentSegment = first.getFileName().toString();
             position = 0L;
             channel = FileChannel.open(first, StandardOpenOption.READ);
+            invalidateBuffer();
         }
 
         private boolean openNextSegment() throws IOException {
@@ -1048,36 +1170,85 @@ public class SyslogWalService {
                     currentSegment = name;
                     position = 0L;
                     channel = FileChannel.open(path, StandardOpenOption.READ);
+                    invalidateBuffer();
                     return true;
                 }
             }
             return false;
         }
 
+        /** 丢弃读缓冲：position 被回退（等待 durable）或通道切换后必须重定位。 */
+        private void invalidateBuffer() {
+            readBufPos = 0;
+            readBufLen = 0;
+            needSeek = true;
+        }
+
+        /** 从磁盘补一段进读缓冲；EOF 返回 false。 */
+        private boolean fillBuffer() throws IOException {
+            if (readBuf == null) readBuf = ByteBuffer.allocate(READ_BUF_SIZE);
+            if (needSeek) {
+                readBufBase = position;
+                readBufPos = 0;
+                readBufLen = 0;
+                channel.position(position);
+                needSeek = false;
+            }
+            byte[] arr = readBuf.array();
+            if (readBufPos > 0) {
+                int tail = readBufLen - readBufPos;
+                if (tail > 0) System.arraycopy(arr, readBufPos, arr, 0, tail);
+                readBufBase += readBufPos;
+                readBufLen = tail;
+                readBufPos = 0;
+            }
+            if (readBufLen == arr.length) return false;
+            ((java.nio.Buffer) readBuf).clear();
+            ((java.nio.Buffer) readBuf).position(readBufLen);
+            int n = channel.read(readBuf);
+            if (n <= 0) return false;
+            readBufLen += n;
+            return readBufLen > readBufPos;
+        }
+
         private byte[] readLine() throws IOException {
             long start = position;
-            ByteArrayOutputStream output = new ByteArrayOutputStream(2048);
+            ByteArrayOutputStream overflow = null;
-            ByteBuffer buffer = ByteBuffer.allocate(8192);
             while (true) {
-                buffer.clear();
+                if (readBufPos >= readBufLen && !fillBuffer()) {
-                channel.position(position);
+                    // EOF：半行丢弃并回退（与旧实现一致，未完成尾行由启动期 repair 处理）。
-                int count = channel.read(buffer);
-                if (count < 0 || count == 0) {
                     position = start;
                     return null;
                 }
-                buffer.flip();
+                byte[] arr = readBuf.array();
-                int consumed = 0;
+                for (int i = readBufPos; i < readBufLen; i++) {
-                while (buffer.hasRemaining()) {
+                    if (arr[i] == (byte) '\n') {
-                    byte value = buffer.get();
+                        int chunk = i - readBufPos;
-                    consumed++;
+                        byte[] line;
-                    if (value == (byte) '\n') {
+                        if (overflow == null) {
-                        position += consumed;
+                            line = new byte[chunk];
-                        return output.toByteArray();
+                            System.arraycopy(arr, readBufPos, line, 0, chunk);
+                        } else {
+                            overflow.write(arr, readBufPos, chunk);
+                            line = overflow.toByteArray();
                         }
-                    output.write(value);
+                        readBufPos = i + 1;
+                        position = readBufBase + readBufPos;
+                        return line;
                     }
-                position += consumed;
+                }
+                // 本块无换行：整体并入溢出流继续读
+                if (overflow == null) {
+                    overflow = new ByteArrayOutputStream(Math.max(4096, (readBufLen - readBufPos) * 2));
+                }
+                overflow.write(arr, readBufPos, readBufLen - readBufPos);
+                if (overflow.size() > 32_000_000) {
+                    position = start;
+                    throw new IOException("WAL 行超长（32MB 内无换行）: segment=" + currentSegment
+                            + ", offset=" + start);
+                }
+                readBufPos = readBufLen;
+                position = readBufBase + readBufPos;
             }
         }
 

haobang-security-dm/syslog-serve/src/main/java/com/netty/SyslogServerBoth.java

@@ -126,8 +126,12 @@ public class SyslogServerBoth {
                 // [SYSLOG-ALARM][NINGRESS][已修复] backlog/接收缓冲配置化；实际生效上限仍受操作系统 somaxconn/rmem_max 约束。
                 .option(ChannelOption.SO_BACKLOG, properties.getSyslogTcpBacklog())
                 .childOption(ChannelOption.SO_KEEPALIVE, true)
-                .childOption(ChannelOption.AUTO_READ, true)
+                .childOption(ChannelOption.AUTO_READ, true);
-                .childOption(ChannelOption.SO_RCVBUF, properties.getSyslogTcpReceiveBufferBytes());
+        // [SYSLOG-VERIFY] SO_RCVBUF<=0 时不显式设置：显式设置会禁用 Linux window scaling（窗口锁死 64KB）
+        // 以及 Windows 接收窗口自动调优，实测会导致突发流量下窗口塌缩与吞吐骤降。
+        if (properties.getSyslogTcpReceiveBufferBytes() > 0) {
+            b.childOption(ChannelOption.SO_RCVBUF, properties.getSyslogTcpReceiveBufferBytes());
+        }
 
         tcpChannelFuture = b.bind(tcpPort).sync();
         logger.info("TCP Syslog server started on port {}", tcpPort);
@@ -147,8 +151,11 @@ public class SyslogServerBoth {
                 .handler(new SyslogUdpChannelInitializer(syslogCharset, walService, deviceResolver,
                         !properties.isSyslogDispatchTerminalRecordEnabled(), ipMetrics))
                 // [SYSLOG-ALARM][NINGRESS][已修复] 显式配置 UDP 接收缓冲；UDP 仍无端到端确认，强可靠设备应改用 TCP/TLS 或 RELP。
-                .option(ChannelOption.SO_BROADCAST, true)
+                .option(ChannelOption.SO_BROADCAST, true);
-                .option(ChannelOption.SO_RCVBUF, properties.getSyslogUdpReceiveBufferBytes());
+        // [SYSLOG-VERIFY] 与 TCP 一致：<=0 表示交给操作系统自适应。
+        if (properties.getSyslogUdpReceiveBufferBytes() > 0) {
+            b.option(ChannelOption.SO_RCVBUF, properties.getSyslogUdpReceiveBufferBytes());
+        }
 
         udpChannelFuture = b.bind(udpPort).sync();
         logger.info("UDP Syslog server started on port {}", udpPort);