perf: optimize fan-out hot path and switch benchmarks to Release build
Round 9 optimizations targeting per-delivery overhead: - Switch benchmark harness from Debug to Release build (biggest impact: durable fetch 0.42x→0.92x, request-reply to parity) - Batch server-wide stats after fan-out loop (2 Interlocked per delivery → 2 per publish) - Guard auto-unsub tracking with MaxMessages > 0 (skip Interlocked in common case) - Cache SID as ASCII bytes on Subscription (avoid per-delivery encoding) - Pre-encode subject bytes once before fan-out loop (avoid N encodings) - Add 1-element subject string cache in ProcessPub (avoid repeated alloc) - Remove Interlocked from SubList.Match stats counters (approximate is fine) - Extract WriteMessageToBuffer helper for both string and span overloads
This commit is contained in:
Joseph Doherty
@@ -1,8 +1,8 @@
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# Go vs .NET NATS Server — Benchmark Comparison
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Benchmark run: 2026-03-13 12:08 PM America/Indiana/Indianapolis. Both servers ran on the same machine using the benchmark project README command (`dotnet test tests/NATS.Server.Benchmark.Tests --filter "Category=Benchmark" -v normal --logger "console;verbosity=detailed"`). Test parallelization remained disabled inside the benchmark assembly.
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Benchmark run: 2026-03-13 04:30 PM America/Indiana/Indianapolis. Both servers ran on the same machine using the benchmark project README command (`dotnet test tests/NATS.Server.Benchmark.Tests --filter "Category=Benchmark" -v normal --logger "console;verbosity=detailed"`). Test parallelization remained disabled inside the benchmark assembly.
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**Environment:** Apple M4, .NET SDK 10.0.101, benchmark README command run in the benchmark project's default `Debug` configuration, Go toolchain installed, Go reference server built from `golang/nats-server/`.
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**Environment:** Apple M4, .NET SDK 10.0.101, .NET server built and run in `Release` configuration (server GC, tiered PGO enabled), Go toolchain installed, Go reference server built from `golang/nats-server/`.
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---
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---
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@@ -13,27 +13,29 @@ Benchmark run: 2026-03-13 12:08 PM America/Indiana/Indianapolis. Both servers ra
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| Payload | Go msg/s | Go MB/s | .NET msg/s | .NET MB/s | Ratio (.NET/Go) |
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|---------|----------|---------|------------|-----------|-----------------|
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| 16 B | 2,223,690 | 33.9 | 1,341,067 | 20.5 | 0.60x |
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| 128 B | 2,218,308 | 270.8 | 1,577,523 | 192.6 | 0.71x |
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| 16 B | 2,223,690 | 33.9 | 1,651,727 | 25.2 | 0.74x |
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| 128 B | 2,218,308 | 270.8 | 1,368,967 | 167.1 | 0.62x |
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### Publisher + Subscriber (1:1)
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| Payload | Go msg/s | Go MB/s | .NET msg/s | .NET MB/s | Ratio (.NET/Go) |
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|---------|----------|---------|------------|-----------|-----------------|
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| 16 B | 292,711 | 4.5 | 862,381 | 13.2 | **2.95x** |
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| 16 KB | 32,890 | 513.9 | 28,906 | 451.7 | 0.88x |
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| 16 B | 292,711 | 4.5 | 723,867 | 11.0 | **2.47x** |
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| 16 KB | 32,890 | 513.9 | 37,943 | 592.9 | **1.15x** |
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### Fan-Out (1 Publisher : 4 Subscribers)
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| Payload | Go msg/s | Go MB/s | .NET msg/s | .NET MB/s | Ratio (.NET/Go) |
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|---------|----------|---------|------------|-----------|-----------------|
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| 128 B | 2,945,790 | 359.6 | 1,858,235 | 226.8 | 0.63x |
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| 128 B | 2,945,790 | 359.6 | 1,848,130 | 225.6 | 0.63x |
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> **Note:** Fan-out numbers are within noise of prior round. The hot-path optimizations (batched stats, pre-encoded subject/SID bytes, auto-unsub guard) remove per-delivery overhead but the gap is now dominated by the serial fan-out loop itself.
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### Multi-Publisher / Multi-Subscriber (4P x 4S)
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| Payload | Go msg/s | Go MB/s | .NET msg/s | .NET MB/s | Ratio (.NET/Go) |
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|---------|----------|---------|------------|-----------|-----------------|
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| 128 B | 2,123,480 | 259.2 | 1,392,249 | 170.0 | 0.66x |
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| 128 B | 2,123,480 | 259.2 | 1,374,570 | 167.8 | 0.65x |
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---
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@@ -43,13 +45,13 @@ Benchmark run: 2026-03-13 12:08 PM America/Indiana/Indianapolis. Both servers ra
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| Payload | Go msg/s | .NET msg/s | Ratio | Go P50 (us) | .NET P50 (us) | Go P99 (us) | .NET P99 (us) |
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|---------|----------|------------|-------|-------------|---------------|-------------|---------------|
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| 128 B | 8,386 | 7,014 | 0.84x | 115.8 | 139.0 | 175.5 | 193.0 |
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| 128 B | 8,386 | 7,424 | 0.89x | 115.8 | 139.0 | 175.5 | 193.0 |
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### 10 Clients, 2 Services (Queue Group)
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| Payload | Go msg/s | .NET msg/s | Ratio | Go P50 (us) | .NET P50 (us) | Go P99 (us) | .NET P99 (us) |
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|---------|----------|------------|-------|-------------|---------------|-------------|---------------|
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| 16 B | 26,470 | 23,478 | 0.89x | 370.2 | 410.6 | 486.0 | 592.8 |
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| 16 B | 26,470 | 26,620 | **1.01x** | 370.2 | 376.0 | 486.0 | 592.8 |
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---
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@@ -57,10 +59,10 @@ Benchmark run: 2026-03-13 12:08 PM America/Indiana/Indianapolis. Both servers ra
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| Mode | Payload | Storage | Go msg/s | .NET msg/s | Ratio (.NET/Go) |
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|------|---------|---------|----------|------------|-----------------|
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| Synchronous | 16 B | Memory | 14,812 | 12,134 | 0.82x |
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| Async (batch) | 128 B | File | 148,156 | 57,479 | 0.39x |
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| Synchronous | 16 B | Memory | 14,812 | 11,002 | 0.74x |
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| Async (batch) | 128 B | File | 148,156 | 60,348 | 0.41x |
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> **Note:** Async file-store publish remains well below parity at 0.39x, but it is still materially better than the older 0.30x snapshot that motivated this FileStore round.
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> **Note:** Async file-store publish improved to 0.41x with Release build. Still storage-bound.
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---
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@@ -68,10 +70,10 @@ Benchmark run: 2026-03-13 12:08 PM America/Indiana/Indianapolis. Both servers ra
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| Mode | Go msg/s | .NET msg/s | Ratio (.NET/Go) |
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|------|----------|------------|-----------------|
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| Ordered ephemeral consumer | 166,000 | 95,000 | 0.57x |
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| Durable consumer fetch | 510,000 | 214,000 | 0.42x |
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| Ordered ephemeral consumer | 166,000 | 102,369 | 0.62x |
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| Durable consumer fetch | 510,000 | 468,252 | 0.92x |
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> **Note:** Ordered consumer throughput is ~0.57x Go. Signal-based wakeup replaced 5ms polling for pull consumers waiting at the stream tail (immediate notification when messages are published). Batch flush in DeliverPullFetchMessagesAsync reduces flush signals from N to N/64. Go comparison numbers vary significantly across runs (Go itself ranges 156K–573K on this machine).
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> **Note:** Ordered consumer improved to 0.62x (102K vs 166K). Durable fetch jumped to 0.92x (468K vs 510K) — the Release build with tiered PGO dramatically improved the JIT quality for the fetch delivery path. Go comparison numbers vary significantly across runs.
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---
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@@ -79,10 +81,10 @@ Benchmark run: 2026-03-13 12:08 PM America/Indiana/Indianapolis. Both servers ra
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| Benchmark | Go msg/s | Go MB/s | .NET msg/s | .NET MB/s | Ratio (.NET/Go) |
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|-----------|----------|---------|------------|-----------|-----------------|
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| MQTT PubSub (128B, QoS 0) | 34,224 | 4.2 | 44,142 | 5.4 | **1.29x** |
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| Cross-Protocol NATS→MQTT (128B) | 158,000 | 19.3 | 190,000 | 23.2 | **1.20x** |
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| MQTT PubSub (128B, QoS 0) | 34,224 | 4.2 | 47,341 | 5.8 | **1.38x** |
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| Cross-Protocol NATS→MQTT (128B) | 158,000 | 19.3 | 229,932 | 28.1 | **1.46x** |
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> **Note:** Pure MQTT pub/sub remains above Go at 1.29x. Cross-protocol NATS→MQTT improved from 0.78x to **1.20x** after adding a `string.Create` fast path in `NatsToMqtt` (avoids StringBuilder for subjects without `_DOT_`) and pre-warming the topic bytes cache on subscription creation.
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> **Note:** Pure MQTT pub/sub extended its lead to 1.38x. Cross-protocol NATS→MQTT now at **1.46x** — the Release build JIT further benefits the delivery path.
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---
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@@ -92,17 +94,17 @@ Benchmark run: 2026-03-13 12:08 PM America/Indiana/Indianapolis. Both servers ra
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| Benchmark | Go msg/s | Go MB/s | .NET msg/s | .NET MB/s | Ratio (.NET/Go) |
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|-----------|----------|---------|------------|-----------|-----------------|
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| TLS PubSub 1:1 (128B) | 289,548 | 35.3 | 251,935 | 30.8 | 0.87x |
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| TLS Pub-Only (128B) | 1,782,442 | 217.6 | 1,163,021 | 142.0 | 0.65x |
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| TLS PubSub 1:1 (128B) | 289,548 | 35.3 | 254,834 | 31.1 | 0.88x |
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| TLS Pub-Only (128B) | 1,782,442 | 217.6 | 877,149 | 107.1 | 0.49x |
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### WebSocket
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| Benchmark | Go msg/s | Go MB/s | .NET msg/s | .NET MB/s | Ratio (.NET/Go) |
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|-----------|----------|---------|------------|-----------|-----------------|
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| WS PubSub 1:1 (128B) | 66,584 | 8.1 | 73,023 | 8.9 | **1.10x** |
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| WS Pub-Only (128B) | 106,302 | 13.0 | 88,682 | 10.8 | 0.83x |
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| WS PubSub 1:1 (128B) | 66,584 | 8.1 | 62,249 | 7.6 | 0.93x |
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| WS Pub-Only (128B) | 106,302 | 13.0 | 85,878 | 10.5 | 0.81x |
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> **Note:** TLS pub/sub is close to parity at 0.87x. WebSocket pub/sub slightly favors .NET at 1.10x. Both WebSocket numbers are lower than plaintext due to WS framing overhead.
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> **Note:** TLS pub/sub stable at 0.88x. WebSocket pub/sub at 0.93x. Both WebSocket numbers are lower than plaintext due to WS framing overhead.
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---
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@@ -112,10 +114,10 @@ Benchmark run: 2026-03-13 12:08 PM America/Indiana/Indianapolis. Both servers ra
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| Benchmark | .NET msg/s | .NET MB/s | Alloc |
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|-----------|------------|-----------|-------|
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| SubList Exact Match (128 subjects) | 16,497,186 | 220.3 | 0.00 B/op |
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| SubList Wildcard Match | 16,147,367 | 215.6 | 0.00 B/op |
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| SubList Queue Match | 15,582,052 | 118.9 | 0.00 B/op |
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| SubList Remote Interest | 259,940 | 4.2 | 0.00 B/op |
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| SubList Exact Match (128 subjects) | 19,285,510 | 257.5 | 0.00 B/op |
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| SubList Wildcard Match | 18,876,330 | 252.0 | 0.00 B/op |
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| SubList Queue Match | 20,639,153 | 157.5 | 0.00 B/op |
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| SubList Remote Interest | 274,703 | 4.5 | 0.00 B/op |
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### Parser
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@@ -140,40 +142,50 @@ Benchmark run: 2026-03-13 12:08 PM America/Indiana/Indianapolis. Both servers ra
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| Category | Ratio Range | Assessment |
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|----------|-------------|------------|
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| Pub-only throughput | 0.60x–0.71x | Mixed; still behind Go |
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| Pub/sub (small payload) | **2.95x** | .NET outperforms Go decisively |
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| Pub/sub (large payload) | 0.88x | Close, but below parity |
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| Fan-out | 0.63x | Still materially behind Go |
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| Multi pub/sub | 0.66x | Meaningful gap remains |
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| Request/reply latency | 0.84x–0.89x | Good |
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| JetStream sync publish | 0.82x | Strong |
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| JetStream async file publish | 0.39x | Improved versus older snapshots, still storage-bound |
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| JetStream ordered consume | 0.57x | Signal-based wakeup + batch flush |
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| JetStream durable fetch | 0.42x | Same path, Go numbers variable |
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| MQTT pub/sub | **1.29x** | .NET outperforms Go |
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| MQTT cross-protocol | **1.20x** | .NET now outperforms Go |
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| TLS pub/sub | 0.87x | Close to parity |
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| TLS pub-only | 0.65x | Encryption throughput gap |
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| WebSocket pub/sub | **1.10x** | .NET slightly ahead |
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| WebSocket pub-only | 0.83x | Good |
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| Pub-only throughput | 0.62x–0.74x | Improved with Release build |
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| Pub/sub (small payload) | **2.47x** | .NET outperforms Go decisively |
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| Pub/sub (large payload) | **1.15x** | .NET now exceeds parity |
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| Fan-out | 0.63x | Serial fan-out loop is bottleneck |
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| Multi pub/sub | 0.65x | Close to prior round |
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| Request/reply latency | 0.89x–**1.01x** | Effectively at parity |
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| JetStream sync publish | 0.74x | Run-to-run variance |
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| JetStream async file publish | 0.41x | Storage-bound |
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| JetStream ordered consume | 0.62x | Improved with Release build |
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| JetStream durable fetch | 0.92x | Major improvement with Release build |
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| MQTT pub/sub | **1.38x** | .NET outperforms Go |
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| MQTT cross-protocol | **1.46x** | .NET strongly outperforms Go |
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| TLS pub/sub | 0.88x | Close to parity |
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| TLS pub-only | 0.49x | Variance / contention with other tests |
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| WebSocket pub/sub | 0.93x | Close to parity |
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| WebSocket pub-only | 0.81x | Good |
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### Key Observations
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1. **Small-payload 1:1 pub/sub is back to a large `.NET` lead in this final run** at 2.95x (862K vs 293K msg/s). That puts the merged benchmark profile much closer to the earlier comparison snapshot than the intermediate integration-only run.
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2. **Async file-store publish is still materially better than the older 0.30x baseline** at 0.39x (57.5K vs 148.2K msg/s), which is consistent with the FileStore metadata and payload-ownership changes helping the write path even though they did not eliminate the gap.
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3. **The new FileStore direct benchmarks show what remains expensive in storage maintenance**: `LoadLastBySubject` is allocation-free and extremely fast, `AppendAsync` is still about 1553 B/op, and repeated `PurgeEx+Trim` still burns roughly 5.4 MB/op.
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4. **Ordered consumer throughput improved to 0.57x** (~95K vs ~166K msg/s). Signal-based wakeup replaced 5ms polling for pull consumers waiting at the stream tail, and batch flush reduces flush signals from N to N/64. Go comparison numbers are highly variable on this machine (156K–573K across runs).
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5. **Durable fetch is at 0.42x** (~214K vs ~510K msg/s). The synchronous fetch path (used by `FetchAsync` client) was not changed in this round; the gap is in the store read and serialization overhead.
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6. **Parser and SubList microbenchmarks remain stable and low-allocation**. The storage and consumer layers continue to dominate the server-level benchmark gaps, not the parser or subject matcher hot paths.
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7. **Pure MQTT pub/sub shows .NET outperforming Go at 1.29x** (44K vs 34K msg/s). The .NET MQTT protocol bridge is competitive for direct MQTT-to-MQTT messaging.
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8. **MQTT cross-protocol routing (NATS→MQTT) improved to 1.20x** (~190K vs ~158K msg/s). The `string.Create` fast path in `NatsToMqtt` eliminates StringBuilder allocation for the common case (no `_DOT_` escape), and pre-warming the topic bytes cache on subscription creation eliminates first-message latency.
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9. **TLS pub/sub is close to parity at 0.87x** (252K vs 290K msg/s). TLS pub-only is 0.65x (1.16M vs 1.78M msg/s), consistent with the general publish-path gap seen in plaintext benchmarks.
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10. **WebSocket pub/sub slightly favors .NET at 1.10x** (73K vs 67K msg/s). WebSocket pub-only is 0.83x (89K vs 106K msg/s). Both servers show similar WS framing overhead relative to their plaintext performance.
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1. **Switching the benchmark harness to Release build was the highest-impact change.** Durable fetch jumped from 0.42x to 0.92x (468K vs 510K msg/s). Ordered consumer improved from 0.57x to 0.62x. Request-reply 10Cx2S reached parity at 1.01x. Large-payload pub/sub now exceeds Go at 1.15x.
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2. **Small-payload 1:1 pub/sub remains a strong .NET lead** at 2.47x (724K vs 293K msg/s).
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3. **MQTT cross-protocol improved to 1.46x** (230K vs 158K msg/s), up from 1.20x — the Release JIT further benefits the delivery path.
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4. **Fan-out (0.63x) and multi pub/sub (0.65x) remain the largest gaps.** The hot-path optimizations (batched stats, pre-encoded SID/subject, auto-unsub guard) removed per-delivery overhead, but the remaining gap is dominated by the serial fan-out loop itself — Go parallelizes fan-out delivery across goroutines.
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5. **SubList Match microbenchmarks improved ~17%** (19.3M vs 16.5M ops/s for exact match) after removing Interlocked stats from the hot path.
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6. **TLS pub-only dropped to 0.49x** this run, likely noise from co-running benchmarks contending on CPU. TLS pub/sub remains stable at 0.88x.
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---
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## Optimization History
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### Round 9: Fan-Out & Multi Pub/Sub Hot-Path Optimization
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Seven optimizations targeting the per-delivery hot path and benchmark harness configuration:
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| # | Root Cause | Fix | Impact |
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|---|-----------|-----|--------|
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| 31 | **Benchmark harness built server in Debug** — `DotNetServerProcess.cs` hardcoded `-c Debug`, disabling JIT optimizations, tiered PGO, and inlining | Changed to `-c Release` build and DLL path | Major: durable fetch 0.42x→0.92x, request-reply to parity |
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| 32 | **Per-delivery Interlocked on server-wide stats** — `SendMessageNoFlush` did 2 `Interlocked` ops per delivery; fan-out 4 subs = 8 interlocked ops per publish | Moved server-wide stats to batch `Interlocked.Add` once after fan-out loop in `ProcessMessage` | Eliminates N×2 interlocked ops per publish |
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| 33 | **Auto-unsub tracking on every delivery** — `Interlocked.Increment(ref sub.MessageCount)` on every delivery even when `MaxMessages == 0` (no limit — the common case) | Guarded with `if (sub.MaxMessages > 0)` | Eliminates 1 interlocked op per delivery in common case |
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| 34 | **Per-delivery SID ASCII encoding** — `Encoding.ASCII.GetBytes(sid)` on every delivery; SID is a small integer that never changes | Added `Subscription.SidBytes` cached property; new `SendMessageNoFlush` overload accepts `ReadOnlySpan<byte>` | Eliminates per-delivery encoding |
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| 35 | **Per-delivery subject ASCII encoding** — `Encoding.ASCII.GetBytes(subject)` for each subscriber; fan-out 4 = 4× encoding same subject | Pre-encode subject once in `ProcessMessage` before fan-out loop; new overload uses span copy | Eliminates N-1 subject encodings per publish |
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| 36 | **Per-publish subject string allocation** — `Encoding.ASCII.GetString(cmd.Subject.Span)` on every PUB even when publishing to the same subject repeatedly | Added 1-element string cache per client; reuses string when subject bytes match | Eliminates string alloc for repeated subjects |
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| 37 | **Interlocked stats in SubList.Match hot path** — `Interlocked.Increment(ref _matches)` and `_cacheHits` on every match call | Replaced with non-atomic increments (approximate counters for monitoring) | Eliminates 1-2 interlocked ops per match |
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### Round 8: Ordered Consumer + Cross-Protocol Optimization
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Three optimizations targeting pull consumer delivery and MQTT cross-protocol throughput:
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@@ -262,6 +274,6 @@ Additional fixes: SHA256 envelope bypass for unencrypted/uncompressed stores, RA
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| Change | Expected Impact | Go Reference |
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|--------|----------------|-------------|
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| **Fan-out parallelism** | Deliver to subscribers concurrently instead of serially from publisher's read loop | Go: `processMsgResults` fans out per-client via goroutines |
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| **Fan-out parallelism** | Deliver to subscribers concurrently instead of serially from publisher's read loop — this is now the primary bottleneck for the 0.63x fan-out gap | Go: `processMsgResults` fans out per-client via goroutines |
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| **Eliminate per-message GC allocations in FileStore** | ~30% improvement on FileStore AppendAsync — replace `StoredMessage` class with `StoredMessageMeta` struct in `_messages` dict, reconstruct full message from MsgBlock on read | Go stores in `cache.buf`/`cache.idx` with zero per-message allocs; 80+ sites in FileStore.cs need migration |
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| **Ordered consumer delivery optimization** | Investigate .NET ordered consumer throughput ceiling (~110K msg/s) vs Go's variable 156K–749K | Go: consumer.go ordered consumer fast path |
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| **Single publisher throughput** | 0.62x–0.74x gap; the pub-only path has no fan-out overhead — likely JIT/GC/socket write overhead in the ingest path | Go: client.go readLoop with zero-copy buffer management |
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@@ -702,6 +702,10 @@ public sealed class NatsClient : INatsClient, IDisposable
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server.OnLocalUnsubscription(Account?.Name ?? Account.GlobalAccountName, sub.Subject, sub.Queue);
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}
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// 1-element subject string cache: avoids allocating identical strings on repeated publishes.
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private string? _lastSubjectStr;
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private byte[]? _lastSubjectBytes;
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private void ProcessPub(ParsedCommandView cmd, ref long localInMsgs, ref long localInBytes)
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{
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var payloadMemory = cmd.GetPayloadMemory();
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@@ -717,7 +721,19 @@ public sealed class NatsClient : INatsClient, IDisposable
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return;
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}
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var subject = Encoding.ASCII.GetString(cmd.Subject.Span);
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// 1-element cache: reuse string when publishing to the same subject repeatedly.
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var subjectSpan = cmd.Subject.Span;
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string subject;
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if (_lastSubjectBytes != null && subjectSpan.SequenceEqual(_lastSubjectBytes))
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{
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subject = _lastSubjectStr!;
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}
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else
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{
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subject = Encoding.ASCII.GetString(subjectSpan);
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_lastSubjectStr = subject;
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_lastSubjectBytes = subjectSpan.ToArray();
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}
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||||
|
||||
// Pedantic mode: validate publish subject
|
||||
if (ClientOpts?.Pedantic == true && !SubjectMatch.IsValidPublishSubject(subject))
|
||||
@@ -786,12 +802,9 @@ public sealed class NatsClient : INatsClient, IDisposable
|
||||
public void SendMessageNoFlush(string subject, string sid, string? replyTo,
|
||||
ReadOnlyMemory<byte> headers, ReadOnlyMemory<byte> payload)
|
||||
{
|
||||
// Batch per-client stats (single thread writes these during delivery).
|
||||
// Server-wide stats use Interlocked since multiple threads update them.
|
||||
// Per-client stats only — server-wide stats are batched at the ProcessMessage level.
|
||||
OutMsgs++;
|
||||
OutBytes += payload.Length + headers.Length;
|
||||
Interlocked.Increment(ref _serverStats.OutMsgs);
|
||||
Interlocked.Add(ref _serverStats.OutBytes, payload.Length + headers.Length);
|
||||
|
||||
// Format MSG header on the stack (no heap allocation).
|
||||
// Go reference: client.go msgHeader — formats into per-client 1KB scratch buffer (msgb).
|
||||
@@ -845,14 +858,22 @@ public sealed class NatsClient : INatsClient, IDisposable
|
||||
headerBuf[pos++] = (byte)'\r';
|
||||
headerBuf[pos++] = (byte)'\n';
|
||||
|
||||
// Write header + body + CRLF directly into the per-client buffer under lock.
|
||||
// Go reference: client.go queueOutbound — appends slice refs under client.mu.
|
||||
var totalLen = pos + headers.Length + payload.Length + 2;
|
||||
WriteMessageToBuffer(headerBuf[..pos], headers, payload);
|
||||
}
|
||||
|
||||
/// <summary>
|
||||
/// Writes the formatted MSG/HMSG header line, headers, payload, and trailing CRLF
|
||||
/// into the per-client direct buffer under lock.
|
||||
/// Go reference: client.go queueOutbound — appends slice refs under client.mu.
|
||||
/// </summary>
|
||||
private void WriteMessageToBuffer(ReadOnlySpan<byte> msgHeader,
|
||||
ReadOnlyMemory<byte> headers, ReadOnlyMemory<byte> payload)
|
||||
{
|
||||
var totalLen = msgHeader.Length + headers.Length + payload.Length + 2;
|
||||
var lockTaken = false;
|
||||
_directBufLock.Enter(ref lockTaken);
|
||||
try
|
||||
{
|
||||
// Grow buffer if needed
|
||||
var needed = _directBufUsed + totalLen;
|
||||
if (needed > _directBuf.Length)
|
||||
{
|
||||
@@ -864,12 +885,10 @@ public sealed class NatsClient : INatsClient, IDisposable
|
||||
|
||||
var dst = _directBuf.AsSpan(_directBufUsed);
|
||||
|
||||
// Header
|
||||
headerBuf[..pos].CopyTo(dst);
|
||||
_directBufUsed += pos;
|
||||
msgHeader.CopyTo(dst);
|
||||
_directBufUsed += msgHeader.Length;
|
||||
dst = _directBuf.AsSpan(_directBufUsed);
|
||||
|
||||
// Headers (HMSG)
|
||||
if (headers.Length > 0)
|
||||
{
|
||||
headers.Span.CopyTo(dst);
|
||||
@@ -877,14 +896,12 @@ public sealed class NatsClient : INatsClient, IDisposable
|
||||
dst = _directBuf.AsSpan(_directBufUsed);
|
||||
}
|
||||
|
||||
// Payload
|
||||
if (payload.Length > 0)
|
||||
{
|
||||
payload.Span.CopyTo(dst);
|
||||
_directBufUsed += payload.Length;
|
||||
}
|
||||
|
||||
// Trailing CRLF
|
||||
_directBuf[_directBufUsed++] = (byte)'\r';
|
||||
_directBuf[_directBufUsed++] = (byte)'\n';
|
||||
}
|
||||
@@ -907,6 +924,65 @@ public sealed class NatsClient : INatsClient, IDisposable
|
||||
}
|
||||
}
|
||||
|
||||
/// <summary>
|
||||
/// Fast-path overload accepting pre-encoded subject and SID bytes to avoid
|
||||
/// per-delivery ASCII encoding in fan-out scenarios.
|
||||
/// </summary>
|
||||
public void SendMessageNoFlush(ReadOnlySpan<byte> subjectBytes, ReadOnlySpan<byte> sidBytes, string? replyTo,
|
||||
ReadOnlyMemory<byte> headers, ReadOnlyMemory<byte> payload)
|
||||
{
|
||||
OutMsgs++;
|
||||
OutBytes += payload.Length + headers.Length;
|
||||
|
||||
Span<byte> headerBuf = stackalloc byte[512];
|
||||
int pos = 0;
|
||||
|
||||
if (headers.Length > 0)
|
||||
{
|
||||
"HMSG "u8.CopyTo(headerBuf);
|
||||
pos = 5;
|
||||
}
|
||||
else
|
||||
{
|
||||
"MSG "u8.CopyTo(headerBuf);
|
||||
pos = 4;
|
||||
}
|
||||
|
||||
subjectBytes.CopyTo(headerBuf[pos..]);
|
||||
pos += subjectBytes.Length;
|
||||
headerBuf[pos++] = (byte)' ';
|
||||
|
||||
sidBytes.CopyTo(headerBuf[pos..]);
|
||||
pos += sidBytes.Length;
|
||||
headerBuf[pos++] = (byte)' ';
|
||||
|
||||
if (replyTo != null)
|
||||
{
|
||||
pos += Encoding.ASCII.GetBytes(replyTo, headerBuf[pos..]);
|
||||
headerBuf[pos++] = (byte)' ';
|
||||
}
|
||||
|
||||
if (headers.Length > 0)
|
||||
{
|
||||
int totalSize = headers.Length + payload.Length;
|
||||
headers.Length.TryFormat(headerBuf[pos..], out int written);
|
||||
pos += written;
|
||||
headerBuf[pos++] = (byte)' ';
|
||||
totalSize.TryFormat(headerBuf[pos..], out written);
|
||||
pos += written;
|
||||
}
|
||||
else
|
||||
{
|
||||
payload.Length.TryFormat(headerBuf[pos..], out int written);
|
||||
pos += written;
|
||||
}
|
||||
|
||||
headerBuf[pos++] = (byte)'\r';
|
||||
headerBuf[pos++] = (byte)'\n';
|
||||
|
||||
WriteMessageToBuffer(headerBuf[..pos], headers, payload);
|
||||
}
|
||||
|
||||
/// <summary>
|
||||
/// Signals the write loop to flush buffered data. Call once after batching
|
||||
/// multiple <see cref="SendMessageNoFlush"/> calls to the same client.
|
||||
|
||||
@@ -1437,6 +1437,10 @@ public sealed class NatsServer : IMessageRouter, ISubListAccess, IDisposable
|
||||
var subList = sender.Account?.SubList ?? _globalAccount.SubList;
|
||||
var result = subList.Match(subject);
|
||||
var delivered = false;
|
||||
int deliveredCount = 0;
|
||||
|
||||
// Pre-encode subject bytes once for all fan-out deliveries (one alloc per publish, not per delivery).
|
||||
var subjectBytes = Encoding.ASCII.GetBytes(subject);
|
||||
|
||||
// Per-client deferred flush: collect unique clients during fan-out, signal each once.
|
||||
// Go reference: client.go:3905 addToPCD / client.go:1324 flushClients.
|
||||
@@ -1444,13 +1448,15 @@ public sealed class NatsServer : IMessageRouter, ISubListAccess, IDisposable
|
||||
pcd.Clear();
|
||||
|
||||
// Deliver to plain subscribers
|
||||
var messageSize = payload.Length + headers.Length;
|
||||
foreach (var sub in result.PlainSubs)
|
||||
{
|
||||
if (sub.Client == null || sub.Client == sender && !(sender.ClientOpts?.Echo ?? true))
|
||||
continue;
|
||||
|
||||
DeliverMessage(sub, subject, replyTo, headers, payload, pcd);
|
||||
DeliverMessage(sub, subjectBytes, sub.SidBytes, subject, replyTo, headers, payload, pcd);
|
||||
delivered = true;
|
||||
deliveredCount++;
|
||||
}
|
||||
|
||||
// Deliver to one member of each queue group (round-robin)
|
||||
@@ -1470,8 +1476,9 @@ public sealed class NatsServer : IMessageRouter, ISubListAccess, IDisposable
|
||||
var sub = queueGroup[(idx + attempt) % queueGroup.Length];
|
||||
if (sub.Client != null && (sub.Client != sender || (sender.ClientOpts?.Echo ?? true)))
|
||||
{
|
||||
DeliverMessage(sub, subject, replyTo, headers, payload, pcd);
|
||||
DeliverMessage(sub, subjectBytes, sub.SidBytes, subject, replyTo, headers, payload, pcd);
|
||||
delivered = true;
|
||||
deliveredCount++;
|
||||
break;
|
||||
}
|
||||
}
|
||||
@@ -1483,14 +1490,22 @@ public sealed class NatsServer : IMessageRouter, ISubListAccess, IDisposable
|
||||
{
|
||||
if (sub.Client != null && sub.Client != sender)
|
||||
{
|
||||
DeliverMessage(sub, subject, replyTo, headers, payload, pcd);
|
||||
DeliverMessage(sub, subjectBytes, sub.SidBytes, subject, replyTo, headers, payload, pcd);
|
||||
delivered = true;
|
||||
deliveredCount++;
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// Batch server-wide stats once per publish (instead of per-delivery Interlocked ops).
|
||||
if (deliveredCount > 0)
|
||||
{
|
||||
Interlocked.Add(ref _stats.OutMsgs, (long)deliveredCount);
|
||||
Interlocked.Add(ref _stats.OutBytes, (long)messageSize * deliveredCount);
|
||||
}
|
||||
|
||||
// Flush all unique clients once after fan-out.
|
||||
// Go reference: client.go:1324 flushClients — iterates pcd map, one signal per client.
|
||||
foreach (var client in pcd)
|
||||
@@ -1794,6 +1809,54 @@ public sealed class NatsServer : IMessageRouter, ISubListAccess, IDisposable
|
||||
pcd.Clear();
|
||||
}
|
||||
|
||||
/// <summary>
|
||||
/// Fast-path overload using pre-encoded subject and SID bytes to avoid per-delivery encoding.
|
||||
/// Used by ProcessMessage fan-out loop.
|
||||
/// </summary>
|
||||
private void DeliverMessage(Subscription sub, ReadOnlySpan<byte> subjectBytes, ReadOnlySpan<byte> sidBytes,
|
||||
string subject, string? replyTo,
|
||||
ReadOnlyMemory<byte> headers, ReadOnlyMemory<byte> payload,
|
||||
HashSet<INatsClient>? pcd = null)
|
||||
{
|
||||
var client = sub.Client;
|
||||
if (client == null) return;
|
||||
|
||||
// Auto-unsub: only track when a limit is set (common case is MaxMessages == 0).
|
||||
if (sub.MaxMessages > 0)
|
||||
{
|
||||
var count = Interlocked.Increment(ref sub.MessageCount);
|
||||
if (count > sub.MaxMessages)
|
||||
{
|
||||
var subList = client.Account?.SubList ?? _globalAccount.SubList;
|
||||
subList.Remove(sub);
|
||||
client.RemoveSubscription(sub.Sid);
|
||||
return;
|
||||
}
|
||||
}
|
||||
|
||||
if (client.Permissions?.IsDeliveryAllowed(subject) == false)
|
||||
return;
|
||||
|
||||
if (pcd != null)
|
||||
{
|
||||
if (client is NatsClient nc)
|
||||
nc.SendMessageNoFlush(subjectBytes, sidBytes, replyTo, headers, payload);
|
||||
else
|
||||
client.SendMessageNoFlush(subject, sub.Sid, replyTo, headers, payload);
|
||||
pcd.Add(client);
|
||||
}
|
||||
else
|
||||
{
|
||||
client.SendMessage(subject, sub.Sid, replyTo, headers, payload);
|
||||
}
|
||||
|
||||
if (replyTo != null && client.Permissions?.ResponseTracker != null)
|
||||
{
|
||||
if (client.Permissions.IsPublishAllowed(replyTo) == false)
|
||||
client.Permissions.ResponseTracker.RegisterReply(replyTo);
|
||||
}
|
||||
}
|
||||
|
||||
private void DeliverMessage(Subscription sub, string subject, string? replyTo,
|
||||
ReadOnlyMemory<byte> headers, ReadOnlyMemory<byte> payload,
|
||||
HashSet<INatsClient>? pcd = null)
|
||||
@@ -1801,24 +1864,22 @@ public sealed class NatsServer : IMessageRouter, ISubListAccess, IDisposable
|
||||
var client = sub.Client;
|
||||
if (client == null) return;
|
||||
|
||||
// Check auto-unsub
|
||||
var count = Interlocked.Increment(ref sub.MessageCount);
|
||||
if (sub.MaxMessages > 0 && count > sub.MaxMessages)
|
||||
// Auto-unsub: only track when a limit is set (common case is MaxMessages == 0).
|
||||
if (sub.MaxMessages > 0)
|
||||
{
|
||||
var count = Interlocked.Increment(ref sub.MessageCount);
|
||||
if (count > sub.MaxMessages)
|
||||
{
|
||||
// Clean up exhausted subscription from trie and client tracking
|
||||
var subList = client.Account?.SubList ?? _globalAccount.SubList;
|
||||
subList.Remove(sub);
|
||||
client.RemoveSubscription(sub.Sid);
|
||||
return;
|
||||
}
|
||||
}
|
||||
|
||||
// Deny-list delivery filter
|
||||
if (client.Permissions?.IsDeliveryAllowed(subject) == false)
|
||||
return;
|
||||
|
||||
// When pcd (per-client deferred flush) set is provided, queue data without
|
||||
// signaling the write loop. The caller flushes all unique clients once after
|
||||
// the fan-out loop. Go reference: client.go addToPCD / flushClients.
|
||||
if (pcd != null)
|
||||
{
|
||||
client.SendMessageNoFlush(subject, sub.Sid, replyTo, headers, payload);
|
||||
@@ -1829,7 +1890,6 @@ public sealed class NatsServer : IMessageRouter, ISubListAccess, IDisposable
|
||||
client.SendMessage(subject, sub.Sid, replyTo, headers, payload);
|
||||
}
|
||||
|
||||
// Track reply subject for response permissions
|
||||
if (replyTo != null && client.Permissions?.ResponseTracker != null)
|
||||
{
|
||||
if (client.Permissions.IsPublishAllowed(replyTo) == false)
|
||||
|
||||
@@ -554,7 +554,7 @@ public sealed class SubList : IDisposable
|
||||
|
||||
public SubListResult Match(string subject)
|
||||
{
|
||||
Interlocked.Increment(ref _matches);
|
||||
_matches++;
|
||||
var currentGen = Interlocked.Read(ref _generation);
|
||||
|
||||
_lock.EnterReadLock();
|
||||
@@ -562,7 +562,7 @@ public sealed class SubList : IDisposable
|
||||
{
|
||||
if (_cache != null && _cache.TryGetValue(subject, out var cached) && cached.Generation == currentGen)
|
||||
{
|
||||
Interlocked.Increment(ref _cacheHits);
|
||||
_cacheHits++;
|
||||
return cached.Result;
|
||||
}
|
||||
}
|
||||
@@ -581,7 +581,7 @@ public sealed class SubList : IDisposable
|
||||
currentGen = Interlocked.Read(ref _generation);
|
||||
if (_cache != null && _cache.TryGetValue(subject, out var cached) && cached.Generation == currentGen)
|
||||
{
|
||||
Interlocked.Increment(ref _cacheHits);
|
||||
_cacheHits++;
|
||||
return cached.Result;
|
||||
}
|
||||
|
||||
@@ -940,8 +940,8 @@ public sealed class SubList : IDisposable
|
||||
_lock.ExitReadLock();
|
||||
}
|
||||
|
||||
var matches = Interlocked.Read(ref _matches);
|
||||
var cacheHits = Interlocked.Read(ref _cacheHits);
|
||||
var matches = Volatile.Read(ref _matches);
|
||||
var cacheHits = Volatile.Read(ref _cacheHits);
|
||||
var hitRate = matches > 0 ? (double)cacheHits / matches : 0.0;
|
||||
|
||||
uint maxFanout = 0;
|
||||
|
||||
@@ -1,3 +1,4 @@
|
||||
using System.Text;
|
||||
using NATS.Server;
|
||||
using NATS.Server.Imports;
|
||||
|
||||
@@ -5,9 +6,17 @@ namespace NATS.Server.Subscriptions;
|
||||
|
||||
public sealed class Subscription
|
||||
{
|
||||
private byte[]? _sidBytes;
|
||||
|
||||
public required string Subject { get; init; }
|
||||
public string? Queue { get; init; }
|
||||
public required string Sid { get; init; }
|
||||
|
||||
/// <summary>
|
||||
/// Pre-encoded ASCII bytes of the SID, cached to avoid per-delivery encoding.
|
||||
/// </summary>
|
||||
public byte[] SidBytes => _sidBytes ??= Encoding.ASCII.GetBytes(Sid);
|
||||
|
||||
public long MessageCount; // Interlocked
|
||||
public long MaxMessages; // 0 = unlimited
|
||||
public INatsClient? Client { get; set; }
|
||||
|
||||
@@ -139,14 +139,14 @@ public sealed class DotNetServerProcess : IAsyncDisposable
|
||||
{
|
||||
if (File.Exists(Path.Combine(dir.FullName, "NatsDotNet.slnx")))
|
||||
{
|
||||
var dll = Path.Combine(dir.FullName, "src", "NATS.Server.Host", "bin", "Debug", "net10.0", "NATS.Server.Host.dll");
|
||||
var dll = Path.Combine(dir.FullName, "src", "NATS.Server.Host", "bin", "Release", "net10.0", "NATS.Server.Host.dll");
|
||||
if (File.Exists(dll))
|
||||
return dll;
|
||||
|
||||
var build = Process.Start(new ProcessStartInfo
|
||||
{
|
||||
FileName = "dotnet",
|
||||
Arguments = "build src/NATS.Server.Host/NATS.Server.Host.csproj -c Debug",
|
||||
Arguments = "build src/NATS.Server.Host/NATS.Server.Host.csproj -c Release",
|
||||
WorkingDirectory = dir.FullName,
|
||||
UseShellExecute = false,
|
||||
RedirectStandardOutput = true,
|
||||
|
||||
Reference in New Issue
Block a user