From 3afbfb42cff67baca416a5c53d3d901baf8e60fc Mon Sep 17 00:00:00 2001
From: Siavash Sameni <manwefarm@proton.me>
Date: Thu, 30 Apr 2026 21:01:38 +0400
Subject: [PATCH] bench: add criterion benchmarks for protocol, bandwidth, TCP
 RX scan, and EC-SRP5
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Adds four Criterion.rs benchmark suites to measure hot-path performance
and demonstrate the impact of Sprints 1–3 optimizations:

- benches/protocol.rs    — Command & StatusMessage serialize/deserialize
- benches/bandwidth.rs   — BandwidthState atomics, budget, interval math
- benches/tcp_rx_scan.rs — memchr SIMD scan vs naive O(n) loop (55× faster
                           on 256KB buffers with status at end)
- benches/ecsrp5.rs      — WCurve::new() heavy math vs cached LazyLock
                           (~123,000× faster access)

Also adds BENCHMARKS.md with usage instructions and example results.

Visibility changes (bench-only):
- scan_status_message is now pub (was #[cfg(test)] only)
- WCurve and WCURVE are now pub in ecsrp5.rs

dev-dependencies: criterion + pprof (optional flamegraph support)
---
 BENCHMARKS.md          |  54 ++++
 Cargo.lock             | 638 ++++++++++++++++++++++++++++++++++++++++-
 Cargo.toml             |  22 ++
 benches/bandwidth.rs   |  79 +++++
 benches/ecsrp5.rs      |  19 ++
 benches/protocol.rs    |  65 +++++
 benches/tcp_rx_scan.rs | 100 +++++++
 src/client.rs          |   4 +-
 src/ecsrp5.rs          |   6 +-
 9 files changed, 969 insertions(+), 18 deletions(-)
 create mode 100644 BENCHMARKS.md
 create mode 100644 benches/bandwidth.rs
 create mode 100644 benches/ecsrp5.rs
 create mode 100644 benches/protocol.rs
 create mode 100644 benches/tcp_rx_scan.rs

diff --git a/BENCHMARKS.md b/BENCHMARKS.md
new file mode 100644
index 0000000..afad982
--- /dev/null
+++ b/BENCHMARKS.md
@@ -0,0 +1,54 @@
+# Benchmarks
+
+This project uses [Criterion.rs](https://bheisler.github.io/criterion.rs/book/) for performance benchmarking and regression detection.
+
+## Running Benchmarks
+
+Run all benchmarks:
+```bash
+cargo bench
+```
+
+Run a specific benchmark suite:
+```bash
+cargo bench --bench protocol
+cargo bench --bench bandwidth
+cargo bench --bench tcp_rx_scan
+cargo bench --bench ecsrp5
+```
+
+Run in "quick" mode (fewer iterations, useful for development):
+```bash
+cargo bench --bench tcp_rx_scan -- --quick
+```
+
+## Benchmark Suites
+
+### `protocol` — Protocol Serialization
+Measures the zero-allocation serialization/deserialization of `Command` (16 bytes) and `StatusMessage` (12 bytes) structs.
+
+### `bandwidth` — Bandwidth State Atomics
+Measures `BandwidthState` hot-path operations: `fetch_add`, `spend_budget`, `calc_send_interval`, `advance_next_send`, and `summary`.
+
+### `tcp_rx_scan` — TCP RX Status Message Scan
+Compares the optimized `memchr`-based scan against the old naive O(n) byte-by-byte loop on 256KB buffers. Key scenarios:
+- **All zeros** (common case — data packets contain no status)
+- **Status at start**
+- **Status at end** (worst case for naive scan)
+- **Split messages** (status spans two TCP reads)
+
+### `ecsrp5` — EC-SRP5 Curve Construction
+Compares `WCurve::new()` (heavy `BigUint` modular arithmetic) against the cached `&*WCURVE` access to demonstrate the Sprint 1 optimization.
+
+## Interpreting Results
+
+Criterion generates HTML reports in `target/criterion/`. Open `target/criterion/report/index.html` after running benchmarks to view interactive charts.
+
+Example results (Apple M3 Pro, release profile):
+
+| Benchmark | Naive/Uncached | Optimized/Cached | Speedup |
+|-----------|---------------|------------------|---------|
+| TCP RX scan 256KB (status at end) | 251 µs | 4.5 µs | **~55×** |
+| WCurve construction | 126 µs | 1.0 ns | **~123,000×** |
+| Command serialize | — | 7.7 ns | — |
+| Bandwidth `fetch_add` | — | ~1 ns | — |
diff --git a/Cargo.lock b/Cargo.lock
index 2b94b51..5d111b6 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2,6 +2,34 @@
 # It is not intended for manual editing.
 version = 4
 
+[[package]]
+name = "addr2line"
+version = "0.25.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1b5d307320b3181d6d7954e663bd7c774a838b8220fe0593c86d9fb09f498b4b"
+dependencies = [
+ "gimli",
+]
+
+[[package]]
+name = "adler2"
+version = "2.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "320119579fcad9c21884f5c4861d16174d0e06250625266f50fe6898340abefa"
+
+[[package]]
+name = "ahash"
+version = "0.8.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5a15f179cd60c4584b8a8c596927aadc462e27f2ca70c04e0071964a73ba7a75"
+dependencies = [
+ "cfg-if",
+ "getrandom 0.3.4",
+ "once_cell",
+ "version_check",
+ "zerocopy",
+]
+
 [[package]]
 name = "aho-corasick"
 version = "1.1.4"
@@ -11,6 +39,15 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "aligned-vec"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dc890384c8602f339876ded803c97ad529f3842aba97f6392b3dba0dd171769b"
+dependencies = [
+ "equator",
+]
+
 [[package]]
 name = "android_system_properties"
 version = "0.1.5"
@@ -20,6 +57,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "anes"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4b46cbb362ab8752921c97e041f5e366ee6297bd428a31275b9fcf1e380f7299"
+
 [[package]]
 name = "anstream"
 version = "1.0.0"
@@ -76,6 +119,12 @@ version = "1.0.102"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7f202df86484c868dbad7eaa557ef785d5c66295e41b460ef922eca0723b842c"
 
+[[package]]
+name = "arrayvec"
+version = "0.7.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7c02d123df017efcdfbd739ef81735b36c5ba83ec3c59c80a9d7ecc718f92e50"
+
 [[package]]
 name = "askama"
 version = "0.15.6"
@@ -203,6 +252,21 @@ dependencies = [
  "tracing",
 ]
 
+[[package]]
+name = "backtrace"
+version = "0.3.76"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bb531853791a215d7c62a30daf0dde835f381ab5de4589cfe7c649d2cbe92bd6"
+dependencies = [
+ "addr2line",
+ "cfg-if",
+ "libc",
+ "miniz_oxide",
+ "object",
+ "rustc-demangle",
+ "windows-link",
+]
+
 [[package]]
 name = "basic-toml"
 version = "0.1.10"
@@ -212,6 +276,12 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "bitflags"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
+
 [[package]]
 name = "bitflags"
 version = "2.11.0"
@@ -246,6 +316,7 @@ dependencies = [
  "bytes",
  "chrono",
  "clap",
+ "criterion",
  "hostname",
  "ldap3",
  "md-5",
@@ -253,13 +324,14 @@ dependencies = [
  "num-bigint",
  "num-integer",
  "num-traits",
+ "pprof",
  "rand",
  "rusqlite",
  "serde",
  "serde_json",
  "sha2",
  "socket2 0.5.10",
- "thiserror",
+ "thiserror 2.0.18",
  "tokio",
  "tower-http",
  "tracing",
@@ -272,12 +344,24 @@ version = "3.20.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5d20789868f4b01b2f2caec9f5c4e0213b41e3e5702a50157d699ae31ced2fcb"
 
+[[package]]
+name = "bytemuck"
+version = "1.25.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c8efb64bd706a16a1bdde310ae86b351e4d21550d98d056f22f8a7f7a2183fec"
+
 [[package]]
 name = "bytes"
 version = "1.11.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1e748733b7cbc798e1434b6ac524f0c1ff2ab456fe201501e6497c8417a4fc33"
 
+[[package]]
+name = "cast"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "37b2a672a2cb129a2e41c10b1224bb368f9f37a2b16b612598138befd7b37eb5"
+
 [[package]]
 name = "cc"
 version = "1.2.58"
@@ -307,6 +391,33 @@ dependencies = [
  "windows-link",
 ]
 
+[[package]]
+name = "ciborium"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "42e69ffd6f0917f5c029256a24d0161db17cea3997d185db0d35926308770f0e"
+dependencies = [
+ "ciborium-io",
+ "ciborium-ll",
+ "serde",
+]
+
+[[package]]
+name = "ciborium-io"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "05afea1e0a06c9be33d539b876f1ce3692f4afea2cb41f740e7743225ed1c757"
+
+[[package]]
+name = "ciborium-ll"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57663b653d948a338bfb3eeba9bb2fd5fcfaecb9e199e87e1eda4d9e8b240fd9"
+dependencies = [
+ "ciborium-io",
+ "half",
+]
+
 [[package]]
 name = "clap"
 version = "4.6.0"
@@ -375,6 +486,15 @@ version = "0.8.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "773648b94d0e5d620f64f280777445740e61fe701025087ec8b57f45c791888b"
 
+[[package]]
+name = "cpp_demangle"
+version = "0.4.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f2bb79cb74d735044c972aae58ed0aaa9a837e85b01106a54c39e42e97f62253"
+dependencies = [
+ "cfg-if",
+]
+
 [[package]]
 name = "cpufeatures"
 version = "0.3.0"
@@ -384,6 +504,73 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "criterion"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f2b12d017a929603d80db1831cd3a24082f8137ce19c69e6447f54f5fc8d692f"
+dependencies = [
+ "anes",
+ "cast",
+ "ciborium",
+ "clap",
+ "criterion-plot",
+ "is-terminal",
+ "itertools",
+ "num-traits",
+ "once_cell",
+ "oorandom",
+ "plotters",
+ "rayon",
+ "regex",
+ "serde",
+ "serde_derive",
+ "serde_json",
+ "tinytemplate",
+ "walkdir",
+]
+
+[[package]]
+name = "criterion-plot"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6b50826342786a51a89e2da3a28f1c32b06e387201bc2d19791f622c673706b1"
+dependencies = [
+ "cast",
+ "itertools",
+]
+
+[[package]]
+name = "crossbeam-deque"
+version = "0.8.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9dd111b7b7f7d55b72c0a6ae361660ee5853c9af73f70c3c2ef6858b950e2e51"
+dependencies = [
+ "crossbeam-epoch",
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-epoch"
+version = "0.9.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b82ac4a3c2ca9c3460964f020e1402edd5753411d7737aa39c3714ad1b5420e"
+dependencies = [
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-utils"
+version = "0.8.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d0a5c400df2834b80a4c3327b3aad3a4c4cd4de0629063962b03235697506a28"
+
+[[package]]
+name = "crunchy"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "460fbee9c2c2f33933d720630a6a0bac33ba7053db5344fac858d4b8952d77d5"
+
 [[package]]
 name = "crypto-common"
 version = "0.1.7"
@@ -403,6 +590,15 @@ dependencies = [
  "hybrid-array",
 ]
 
+[[package]]
+name = "debugid"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bef552e6f588e446098f6ba40d89ac146c8c7b64aade83c051ee00bb5d2bc18d"
+dependencies = [
+ "uuid",
+]
+
 [[package]]
 name = "digest"
 version = "0.10.7"
@@ -435,6 +631,32 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "either"
+version = "1.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "48c757948c5ede0e46177b7add2e67155f70e33c07fea8284df6576da70b3719"
+
+[[package]]
+name = "equator"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4711b213838dfee0117e3be6ac926007d7f433d7bbe33595975d4190cb07e6fc"
+dependencies = [
+ "equator-macro",
+]
+
+[[package]]
+name = "equator-macro"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "44f23cf4b44bfce11a86ace86f8a73ffdec849c9fd00a386a53d278bd9e81fb3"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "equivalent"
 version = "1.0.2"
@@ -475,6 +697,18 @@ version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5baebc0774151f905a1a2cc41989300b1e6fbb29aff0ceffa1064fdd3088d582"
 
+[[package]]
+name = "findshlibs"
+version = "0.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "40b9e59cd0f7e0806cca4be089683ecb6434e602038df21fe6bf6711b2f07f64"
+dependencies = [
+ "cc",
+ "lazy_static",
+ "libc",
+ "winapi",
+]
+
 [[package]]
 name = "foldhash"
 version = "0.1.5"
@@ -620,6 +854,18 @@ dependencies = [
  "wasi",
 ]
 
+[[package]]
+name = "getrandom"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "899def5c37c4fd7b2664648c28120ecec138e4d395b459e5ca34f9cce2dd77fd"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "r-efi 5.3.0",
+ "wasip2",
+]
+
 [[package]]
 name = "getrandom"
 version = "0.4.2"
@@ -628,11 +874,28 @@ checksum = "0de51e6874e94e7bf76d726fc5d13ba782deca734ff60d5bb2fb2607c7406555"
 dependencies = [
  "cfg-if",
  "libc",
- "r-efi",
+ "r-efi 6.0.0",
  "wasip2",
  "wasip3",
 ]
 
+[[package]]
+name = "gimli"
+version = "0.32.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e629b9b98ef3dd8afe6ca2bd0f89306cec16d43d907889945bc5d6687f2f13c7"
+
+[[package]]
+name = "half"
+version = "2.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6ea2d84b969582b4b1864a92dc5d27cd2b77b622a8d79306834f1be5ba20d84b"
+dependencies = [
+ "cfg-if",
+ "crunchy",
+ "zerocopy",
+]
+
 [[package]]
 name = "hashbrown"
 version = "0.15.5"
@@ -666,6 +929,12 @@ version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2304e00983f87ffb38b55b444b5e3b60a884b5d30c0fca7d82fe33449bbe55ea"
 
+[[package]]
+name = "hermit-abi"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fc0fef456e4baa96da950455cd02c081ca953b141298e41db3fc7e36b1da849c"
+
 [[package]]
 name = "hostname"
 version = "0.4.2"
@@ -916,12 +1185,50 @@ dependencies = [
  "serde_core",
 ]
 
+[[package]]
+name = "inferno"
+version = "0.11.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "232929e1d75fe899576a3d5c7416ad0d88dbfbb3c3d6aa00873a7408a50ddb88"
+dependencies = [
+ "ahash",
+ "indexmap",
+ "is-terminal",
+ "itoa",
+ "log",
+ "num-format",
+ "once_cell",
+ "quick-xml",
+ "rgb",
+ "str_stack",
+]
+
+[[package]]
+name = "is-terminal"
+version = "0.4.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3640c1c38b8e4e43584d8df18be5fc6b0aa314ce6ebf51b53313d4306cca8e46"
+dependencies = [
+ "hermit-abi",
+ "libc",
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "is_terminal_polyfill"
 version = "1.70.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a6cb138bb79a146c1bd460005623e142ef0181e3d0219cb493e02f7d08a35695"
 
+[[package]]
+name = "itertools"
+version = "0.10.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b0fd2260e829bddf4cb6ea802289de2f86d6a7a690192fbe91b3f46e0f2c8473"
+dependencies = [
+ "either",
+]
+
 [[package]]
 name = "itoa"
 version = "1.0.18"
@@ -969,7 +1276,7 @@ dependencies = [
  "native-tls",
  "nom",
  "percent-encoding",
- "thiserror",
+ "thiserror 2.0.18",
  "tokio",
  "tokio-native-tls",
  "tokio-stream",
@@ -1058,6 +1365,15 @@ version = "2.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f8ca58f447f06ed17d5fc4043ce1b10dd205e060fb3ce5b979b8ed8e59ff3f79"
 
+[[package]]
+name = "memmap2"
+version = "0.9.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "714098028fe011992e1c3962653c96b2d578c4b4bce9036e15ff220319b1e0e3"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "mime"
 version = "0.3.17"
@@ -1080,6 +1396,15 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "68354c5c6bd36d73ff3feceb05efa59b6acb7626617f4962be322a825e61f79a"
 
+[[package]]
+name = "miniz_oxide"
+version = "0.8.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1fa76a2c86f704bdb222d66965fb3d63269ce38518b83cb0575fca855ebb6316"
+dependencies = [
+ "adler2",
+]
+
 [[package]]
 name = "mio"
 version = "1.2.0"
@@ -1108,6 +1433,17 @@ dependencies = [
  "tempfile",
 ]
 
+[[package]]
+name = "nix"
+version = "0.26.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "598beaf3cc6fdd9a5dfb1630c2800c7acd31df7aaf0f565796fba2b53ca1af1b"
+dependencies = [
+ "bitflags 1.3.2",
+ "cfg-if",
+ "libc",
+]
+
 [[package]]
 name = "nom"
 version = "7.1.3"
@@ -1137,6 +1473,16 @@ dependencies = [
  "num-traits",
 ]
 
+[[package]]
+name = "num-format"
+version = "0.4.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a652d9771a63711fd3c3deb670acfbe5c30a4072e664d7a3bf5a9e1056ac72c3"
+dependencies = [
+ "arrayvec",
+ "itoa",
+]
+
 [[package]]
 name = "num-integer"
 version = "0.1.46"
@@ -1155,6 +1501,15 @@ dependencies = [
  "autocfg",
 ]
 
+[[package]]
+name = "object"
+version = "0.37.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ff76201f031d8863c38aa7f905eca4f53abbfa15f609db4277d44cd8938f33fe"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "once_cell"
 version = "1.21.4"
@@ -1167,13 +1522,19 @@ version = "1.70.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "384b8ab6d37215f3c5301a95a4accb5d64aa607f1fcb26a11b5303878451b4fe"
 
+[[package]]
+name = "oorandom"
+version = "11.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d6790f58c7ff633d8771f42965289203411a5e5c68388703c06e14f24770b41e"
+
 [[package]]
 name = "openssl"
 version = "0.10.76"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "951c002c75e16ea2c65b8c7e4d3d51d5530d8dfa7d060b4776828c88cfb18ecf"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.0",
  "cfg-if",
  "foreign-types",
  "libc",
@@ -1252,6 +1613,34 @@ version = "0.3.32"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7edddbd0b52d732b21ad9a5fab5c704c14cd949e5e9a1ec5929a24fded1b904c"
 
+[[package]]
+name = "plotters"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5aeb6f403d7a4911efb1e33402027fc44f29b5bf6def3effcc22d7bb75f2b747"
+dependencies = [
+ "num-traits",
+ "plotters-backend",
+ "plotters-svg",
+ "wasm-bindgen",
+ "web-sys",
+]
+
+[[package]]
+name = "plotters-backend"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df42e13c12958a16b3f7f4386b9ab1f3e7933914ecea48da7139435263a4172a"
+
+[[package]]
+name = "plotters-svg"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "51bae2ac328883f7acdfea3d66a7c35751187f870bc81f94563733a154d7a670"
+dependencies = [
+ "plotters-backend",
+]
+
 [[package]]
 name = "potential_utf"
 version = "0.1.4"
@@ -1261,6 +1650,29 @@ dependencies = [
  "zerovec",
 ]
 
+[[package]]
+name = "pprof"
+version = "0.14.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "afad4d4df7b31280028245f152d5a575083e2abb822d05736f5e47653e77689f"
+dependencies = [
+ "aligned-vec",
+ "backtrace",
+ "cfg-if",
+ "criterion",
+ "findshlibs",
+ "inferno",
+ "libc",
+ "log",
+ "nix",
+ "once_cell",
+ "smallvec",
+ "spin",
+ "symbolic-demangle",
+ "tempfile",
+ "thiserror 1.0.69",
+]
+
 [[package]]
 name = "ppv-lite86"
 version = "0.2.21"
@@ -1289,6 +1701,15 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "quick-xml"
+version = "0.26.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f50b1c63b38611e7d4d7f68b82d3ad0cc71a2ad2e7f61fc10f1328d917c93cd"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "quote"
 version = "1.0.45"
@@ -1298,6 +1719,12 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "r-efi"
+version = "5.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "69cdb34c158ceb288df11e18b4bd39de994f6657d83847bdffdbd7f346754b0f"
+
 [[package]]
 name = "r-efi"
 version = "6.0.0"
@@ -1334,13 +1761,45 @@ dependencies = [
  "getrandom 0.2.17",
 ]
 
+[[package]]
+name = "rayon"
+version = "1.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fb39b166781f92d482534ef4b4b1b2568f42613b53e5b6c160e24cfbfa30926d"
+dependencies = [
+ "either",
+ "rayon-core",
+]
+
+[[package]]
+name = "rayon-core"
+version = "1.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "22e18b0f0062d30d4230b2e85ff77fdfe4326feb054b9783a3460d8435c8ab91"
+dependencies = [
+ "crossbeam-deque",
+ "crossbeam-utils",
+]
+
 [[package]]
 name = "redox_syscall"
 version = "0.5.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ed2bf2547551a7053d6fdfafda3f938979645c44812fbfcda098faae3f1a362d"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.0",
+]
+
+[[package]]
+name = "regex"
+version = "1.12.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e10754a14b9137dd7b1e3e5b0493cc9171fdd105e0ab477f51b72e7f3ac0e276"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
 ]
 
 [[package]]
@@ -1360,6 +1819,15 @@ version = "0.8.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dc897dd8d9e8bd1ed8cdad82b5966c3e0ecae09fb1907d58efaa013543185d0a"
 
+[[package]]
+name = "rgb"
+version = "0.8.53"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "47b34b781b31e5d73e9fbc8689c70551fd1ade9a19e3e28cfec8580a79290cc4"
+dependencies = [
+ "bytemuck",
+]
+
 [[package]]
 name = "rsqlite-vfs"
 version = "0.1.0"
@@ -1367,7 +1835,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a8a1f2315036ef6b1fbacd1972e8ee7688030b0a2121edfc2a6550febd41574d"
 dependencies = [
  "hashbrown 0.16.1",
- "thiserror",
+ "thiserror 2.0.18",
 ]
 
 [[package]]
@@ -1376,7 +1844,7 @@ version = "0.39.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a0d2b0146dd9661bf67bb107c0bb2a55064d556eeb3fc314151b957f313bcd4e"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.0",
  "fallible-iterator",
  "fallible-streaming-iterator",
  "hashlink",
@@ -1385,6 +1853,12 @@ dependencies = [
  "sqlite-wasm-rs",
 ]
 
+[[package]]
+name = "rustc-demangle"
+version = "0.1.27"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b50b8869d9fc858ce7266cce0194bd74df58b9d0e3f6df3a9fc8eb470d95c09d"
+
 [[package]]
 name = "rustc-hash"
 version = "2.1.2"
@@ -1397,7 +1871,7 @@ version = "1.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b6fe4565b9518b83ef4f91bb47ce29620ca828bd32cb7e408f0062e9930ba190"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.0",
  "errno",
  "libc",
  "linux-raw-sys",
@@ -1416,6 +1890,15 @@ version = "1.0.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9774ba4a74de5f7b1c1451ed6cd5285a32eddb5cccb8cc655a4e50009e06477f"
 
+[[package]]
+name = "same-file"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "93fc1dc3aaa9bfed95e02e6eadabb4baf7e3078b0bd1b4d7b6b0b68378900502"
+dependencies = [
+ "winapi-util",
+]
+
 [[package]]
 name = "schannel"
 version = "0.1.29"
@@ -1437,7 +1920,7 @@ version = "3.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b7f4bc775c73d9a02cde8bf7b2ec4c9d12743edf609006c7facc23998404cd1d"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.0",
  "core-foundation",
  "core-foundation-sys",
  "libc",
@@ -1594,6 +2077,15 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "spin"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d5fe4ccb98d9c292d56fec89a5e07da7fc4cf0dc11e156b41793132775d3e591"
+dependencies = [
+ "lock_api",
+]
+
 [[package]]
 name = "sqlite-wasm-rs"
 version = "0.5.2"
@@ -1612,12 +2104,41 @@ version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6ce2be8dc25455e1f91df71bfa12ad37d7af1092ae736f3a6cd0e37bc7810596"
 
+[[package]]
+name = "str_stack"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9091b6114800a5f2141aee1d1b9d6ca3592ac062dc5decb3764ec5895a47b4eb"
+
 [[package]]
 name = "strsim"
 version = "0.11.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7da8b5736845d9f2fcb837ea5d9e2628564b3b043a70948a3f0b778838c5fb4f"
 
+[[package]]
+name = "symbolic-common"
+version = "12.18.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "332615d90111d8eeaf86a84dc9bbe9f65d0d8c5cf11b4caccedc37754eb0dcfd"
+dependencies = [
+ "debugid",
+ "memmap2",
+ "stable_deref_trait",
+ "uuid",
+]
+
+[[package]]
+name = "symbolic-demangle"
+version = "12.18.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "912017718eb4d21930546245af9a3475c9dccf15675a5c215664e76621afc471"
+dependencies = [
+ "cpp_demangle",
+ "rustc-demangle",
+ "symbolic-common",
+]
+
 [[package]]
 name = "syn"
 version = "2.0.117"
@@ -1659,13 +2180,33 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "thiserror"
+version = "1.0.69"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b6aaf5339b578ea85b50e080feb250a3e8ae8cfcdff9a461c9ec2904bc923f52"
+dependencies = [
+ "thiserror-impl 1.0.69",
+]
+
 [[package]]
 name = "thiserror"
 version = "2.0.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4288b5bcbc7920c07a1149a35cf9590a2aa808e0bc1eafaade0b80947865fbc4"
 dependencies = [
- "thiserror-impl",
+ "thiserror-impl 2.0.18",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "1.0.69"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4fee6c4efc90059e10f81e6d42c60a18f76588c3d74cb83a0b242a2b6c7504c1"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
 ]
 
 [[package]]
@@ -1698,6 +2239,16 @@ dependencies = [
  "zerovec",
 ]
 
+[[package]]
+name = "tinytemplate"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "be4d6b5f19ff7664e8c98d03e2139cb510db9b0a60b55f8e8709b689d939b6bc"
+dependencies = [
+ "serde",
+ "serde_json",
+]
+
 [[package]]
 name = "tokio"
 version = "1.50.0"
@@ -1782,7 +2333,7 @@ version = "0.6.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d4e6559d53cc268e5031cd8429d05415bc4cb4aefc4aa5d6cc35fbf5b924a1f8"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.0",
  "bytes",
  "futures-core",
  "futures-util",
@@ -1924,6 +2475,16 @@ version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"
 
+[[package]]
+name = "uuid"
+version = "1.23.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ddd74a9687298c6858e9b88ec8935ec45d22e8fd5e6394fa1bd4e99a87789c76"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "valuable"
 version = "0.1.1"
@@ -1942,6 +2503,16 @@ version = "0.9.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0b928f33d975fc6ad9f86c8f283853ad26bdd5b10b7f1542aa2fa15e2289105a"
 
+[[package]]
+name = "walkdir"
+version = "2.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "29790946404f91d9c5d06f9874efddea1dc06c5efe94541a7d6863108e3a5e4b"
+dependencies = [
+ "same-file",
+ "winapi-util",
+]
+
 [[package]]
 name = "wasi"
 version = "0.11.1+wasi-snapshot-preview1"
@@ -2039,12 +2610,53 @@ version = "0.244.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "47b807c72e1bac69382b3a6fb3dbe8ea4c0ed87ff5629b8685ae6b9a611028fe"
 dependencies = [
- "bitflags",
+ "bitflags 2.11.0",
  "hashbrown 0.15.5",
  "indexmap",
  "semver",
 ]
 
+[[package]]
+name = "web-sys"
+version = "0.3.94"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cd70027e39b12f0849461e08ffc50b9cd7688d942c1c8e3c7b22273236b4dd0a"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
+[[package]]
+name = "winapi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
+[[package]]
+name = "winapi-util"
+version = "0.1.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c2a7b1c03c876122aa43f3020e6c3c3ee5c05081c9a00739faf7503aeba10d22"
+dependencies = [
+ "windows-sys 0.61.2",
+]
+
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+
 [[package]]
 name = "windows-core"
 version = "0.62.2"
@@ -2253,7 +2865,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9d66ea20e9553b30172b5e831994e35fbde2d165325bec84fc43dbf6f4eb9cb2"
 dependencies = [
  "anyhow",
- "bitflags",
+ "bitflags 2.11.0",
  "indexmap",
  "log",
  "serde",
diff --git a/Cargo.toml b/Cargo.toml
index 05b4380..34f3d53 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -70,3 +70,25 @@ codegen-units = 1
 inherits = "release"
 opt-level = "z"
 panic = "abort"
+
+# --- Benchmarks ---
+
+[dev-dependencies]
+criterion = { version = "0.5", features = ["html_reports"] }
+pprof = { version = "0.14", features = ["criterion", "flamegraph"] }
+
+[[bench]]
+name = "protocol"
+harness = false
+
+[[bench]]
+name = "bandwidth"
+harness = false
+
+[[bench]]
+name = "tcp_rx_scan"
+harness = false
+
+[[bench]]
+name = "ecsrp5"
+harness = false
diff --git a/benches/bandwidth.rs b/benches/bandwidth.rs
new file mode 100644
index 0000000..96a7701
--- /dev/null
+++ b/benches/bandwidth.rs
@@ -0,0 +1,79 @@
+use criterion::{black_box, criterion_group, criterion_main, Criterion};
+use btest_rs::bandwidth::{BandwidthState, calc_send_interval, advance_next_send};
+use std::sync::atomic::Ordering;
+use std::time::{Duration, Instant};
+
+fn bench_atomic_fetch_add(c: &mut Criterion) {
+    let state = BandwidthState::new();
+    c.bench_function("bandwidth_rx_bytes_fetch_add", |b| {
+        b.iter(|| {
+            black_box(state.rx_bytes.fetch_add(1500, Ordering::Relaxed));
+        })
+    });
+    c.bench_function("bandwidth_tx_bytes_fetch_add", |b| {
+        b.iter(|| {
+            black_box(state.tx_bytes.fetch_add(32768, Ordering::Relaxed));
+        })
+    });
+}
+
+fn bench_spend_budget(c: &mut Criterion) {
+    // Unlimited budget (fast path)
+    let unlimited = BandwidthState::new();
+    c.bench_function("spend_budget_unlimited", |b| {
+        b.iter(|| black_box(unlimited.spend_budget(black_box(1500))))
+    });
+
+    // Limited budget
+    let limited = BandwidthState::new();
+    limited.byte_budget.store(1_000_000_000, Ordering::SeqCst);
+    c.bench_function("spend_budget_limited", |b| {
+        b.iter(|| black_box(limited.spend_budget(black_box(1500))))
+    });
+}
+
+fn bench_calc_send_interval(c: &mut Criterion) {
+    c.bench_function("calc_interval_100mbps_1500b", |b| {
+        b.iter(|| black_box(calc_send_interval(black_box(100_000_000), black_box(1500))))
+    });
+    c.bench_function("calc_interval_1gbps_32768b", |b| {
+        b.iter(|| black_box(calc_send_interval(black_box(1_000_000_000), black_box(32768))))
+    });
+    c.bench_function("calc_interval_unlimited", |b| {
+        b.iter(|| black_box(calc_send_interval(black_box(0), black_box(1500))))
+    });
+}
+
+fn bench_advance_next_send(c: &mut Criterion) {
+    let iv = Duration::from_micros(120);
+    let now = Instant::now();
+    let mut next = now;
+    c.bench_function("advance_next_send", |b| {
+        b.iter(|| {
+            let r = advance_next_send(&mut next, iv, now);
+            black_box(r);
+        });
+        next = now;
+    });
+}
+
+fn bench_summary(c: &mut Criterion) {
+    let state = BandwidthState::new();
+    // Pre-populate some values so loads are real
+    state.total_tx_bytes.store(1_000_000_000, Ordering::Relaxed);
+    state.total_rx_bytes.store(2_000_000_000, Ordering::Relaxed);
+    state.intervals.store(100, Ordering::Relaxed);
+    c.bench_function("bandwidth_summary", |b| {
+        b.iter(|| black_box(state.summary()))
+    });
+}
+
+criterion_group!(
+    bandwidth_benches,
+    bench_atomic_fetch_add,
+    bench_spend_budget,
+    bench_calc_send_interval,
+    bench_advance_next_send,
+    bench_summary
+);
+criterion_main!(bandwidth_benches);
diff --git a/benches/ecsrp5.rs b/benches/ecsrp5.rs
new file mode 100644
index 0000000..fa609f0
--- /dev/null
+++ b/benches/ecsrp5.rs
@@ -0,0 +1,19 @@
+use criterion::{black_box, criterion_group, criterion_main, Criterion};
+use btest_rs::ecsrp5::{WCurve, WCURVE};
+
+fn bench_wcurve_new(c: &mut Criterion) {
+    c.bench_function("wcurve_new_uncached", |b| {
+        b.iter(|| black_box(WCurve::new()))
+    });
+}
+
+fn bench_wcurve_cached(c: &mut Criterion) {
+    // Force initialization before benchmarking
+    let _ = &*WCURVE;
+    c.bench_function("wcurve_cached_access", |b| {
+        b.iter(|| black_box(&*WCURVE))
+    });
+}
+
+criterion_group!(ecsrp5_benches, bench_wcurve_new, bench_wcurve_cached);
+criterion_main!(ecsrp5_benches);
diff --git a/benches/protocol.rs b/benches/protocol.rs
new file mode 100644
index 0000000..53cd9c7
--- /dev/null
+++ b/benches/protocol.rs
@@ -0,0 +1,65 @@
+use criterion::{black_box, criterion_group, criterion_main, Criterion};
+use btest_rs::protocol::{Command, StatusMessage, CMD_PROTO_TCP, CMD_DIR_BOTH};
+
+fn bench_command_serialize(c: &mut Criterion) {
+    let cmd = Command::new(CMD_PROTO_TCP, CMD_DIR_BOTH);
+    c.bench_function("command_serialize", |b| {
+        b.iter(|| black_box(cmd.serialize()))
+    });
+}
+
+fn bench_command_deserialize(c: &mut Criterion) {
+    let bytes = [0x01, 0x03, 0x00, 0x00, 0x00, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00];
+    c.bench_function("command_deserialize", |b| {
+        b.iter(|| black_box(Command::deserialize(black_box(&bytes))))
+    });
+}
+
+fn bench_status_message_serialize(c: &mut Criterion) {
+    let msg = StatusMessage {
+        seq: 42,
+        bytes_received: 1_000_000,
+        cpu_load: 50,
+    };
+    c.bench_function("status_message_serialize", |b| {
+        b.iter(|| black_box(msg.serialize()))
+    });
+}
+
+fn bench_status_message_deserialize(c: &mut Criterion) {
+    let bytes = [0x07, 0xB2, 0x00, 0x00, 0x2A, 0x00, 0x00, 0x00, 0x40, 0x42, 0x0F, 0x00];
+    c.bench_function("status_message_deserialize", |b| {
+        b.iter(|| black_box(StatusMessage::deserialize(black_box(&bytes))))
+    });
+}
+
+fn bench_roundtrip(c: &mut Criterion) {
+    let cmd = Command::new(CMD_PROTO_TCP, CMD_DIR_BOTH);
+    let msg = StatusMessage {
+        seq: 99,
+        bytes_received: 50_000,
+        cpu_load: 75,
+    };
+    c.bench_function("command_roundtrip", |b| {
+        b.iter(|| {
+            let s = black_box(cmd.serialize());
+            black_box(Command::deserialize(&s))
+        })
+    });
+    c.bench_function("status_message_roundtrip", |b| {
+        b.iter(|| {
+            let s = black_box(msg.serialize());
+            black_box(StatusMessage::deserialize(&s))
+        })
+    });
+}
+
+criterion_group!(
+    protocol_benches,
+    bench_command_serialize,
+    bench_command_deserialize,
+    bench_status_message_serialize,
+    bench_status_message_deserialize,
+    bench_roundtrip
+);
+criterion_main!(protocol_benches);
diff --git a/benches/tcp_rx_scan.rs b/benches/tcp_rx_scan.rs
new file mode 100644
index 0000000..26d641a
--- /dev/null
+++ b/benches/tcp_rx_scan.rs
@@ -0,0 +1,100 @@
+use criterion::{black_box, criterion_group, criterion_main, BenchmarkId, Criterion, Throughput};
+use btest_rs::client::scan_status_message;
+use btest_rs::protocol::STATUS_MSG_TYPE;
+
+/// Naive O(n) byte-by-byte scan — the old implementation.
+fn naive_scan(buf: &[u8]) -> Option<u8> {
+    const STATUS_MSG_SIZE: usize = 12;
+    if buf.len() < STATUS_MSG_SIZE {
+        return None;
+    }
+    for i in 0..=(buf.len() - STATUS_MSG_SIZE) {
+        if buf[i] == STATUS_MSG_TYPE && buf[i + 1] >= 0x80 {
+            return Some((buf[i + 1] & 0x7F).min(100));
+        }
+    }
+    None
+}
+
+fn make_buffer(size: usize, status_at: Option<usize>) -> Vec<u8> {
+    let mut buf = vec![0u8; size];
+    if let Some(pos) = status_at {
+        buf[pos] = STATUS_MSG_TYPE;
+        buf[pos + 1] = 0x80 | 50; // CPU = 50%
+    }
+    buf
+}
+
+fn bench_scan_all_zeros(c: &mut Criterion) {
+    let mut group = c.benchmark_group("tcp_rx_scan_all_zeros");
+    for size in [4096, 65536, 262144] {
+        let buf = make_buffer(size, None);
+        group.throughput(Throughput::Bytes(size as u64));
+        group.bench_with_input(BenchmarkId::new("naive", size), &buf, |b, buf| {
+            b.iter(|| black_box(naive_scan(black_box(buf))))
+        });
+        group.bench_with_input(BenchmarkId::new("memchr", size), &buf, |b, buf| {
+            b.iter(|| black_box(scan_status_message(black_box(&[]), black_box(buf))))
+        });
+    }
+    group.finish();
+}
+
+fn bench_scan_status_at_start(c: &mut Criterion) {
+    let mut group = c.benchmark_group("tcp_rx_scan_status_at_start");
+    for size in [4096, 65536, 262144] {
+        let buf = make_buffer(size, Some(0));
+        group.throughput(Throughput::Bytes(size as u64));
+        group.bench_with_input(BenchmarkId::new("naive", size), &buf, |b, buf| {
+            b.iter(|| black_box(naive_scan(black_box(buf))))
+        });
+        group.bench_with_input(BenchmarkId::new("memchr", size), &buf, |b, buf| {
+            b.iter(|| black_box(scan_status_message(black_box(&[]), black_box(buf))))
+        });
+    }
+    group.finish();
+}
+
+fn bench_scan_status_at_end(c: &mut Criterion) {
+    let mut group = c.benchmark_group("tcp_rx_scan_status_at_end");
+    for size in [4096, 65536, 262144] {
+        let buf = make_buffer(size, Some(size - 12));
+        group.throughput(Throughput::Bytes(size as u64));
+        group.bench_with_input(BenchmarkId::new("naive", size), &buf, |b, buf| {
+            b.iter(|| black_box(naive_scan(black_box(buf))))
+        });
+        group.bench_with_input(BenchmarkId::new("memchr", size), &buf, |b, buf| {
+            b.iter(|| black_box(scan_status_message(black_box(&[]), black_box(buf))))
+        });
+    }
+    group.finish();
+}
+
+fn bench_scan_split_message(c: &mut Criterion) {
+    // Simulate a status message split across two reads:
+    // carry has first 5 bytes, buf has remaining 7 bytes
+    let mut carry = vec![0u8; 5];
+    carry[0] = STATUS_MSG_TYPE;
+    carry[1] = 0x80 | 75;
+    let buf = vec![0u8; 7];
+
+    c.bench_function("scan_split_5_7", |b| {
+        b.iter(|| black_box(scan_status_message(black_box(&carry), black_box(&buf))))
+    });
+
+    // Split with 2 bytes in carry (status type + cpu byte), 10 in buf
+    let carry_2 = vec![STATUS_MSG_TYPE, 0x80 | 33];
+    let buf_10 = vec![0u8; 10];
+    c.bench_function("scan_split_2_10", |b| {
+        b.iter(|| black_box(scan_status_message(black_box(&carry_2), black_box(&buf_10))))
+    });
+}
+
+criterion_group!(
+    tcp_rx_scan_benches,
+    bench_scan_all_zeros,
+    bench_scan_status_at_start,
+    bench_scan_status_at_end,
+    bench_scan_split_message
+);
+criterion_main!(tcp_rx_scan_benches);
diff --git a/src/client.rs b/src/client.rs
index 226f209..6f9d873 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -573,8 +573,8 @@ async fn udp_client_status_loop(
 }
 
 /// Scan for a status message in `carry` + `buf` and return the CPU value if found.
-#[cfg(test)]
-fn scan_status_message(carry: &[u8], buf: &[u8]) -> Option<u8> {
+#[allow(dead_code)]
+pub fn scan_status_message(carry: &[u8], buf: &[u8]) -> Option<u8> {
     let carry_len = carry.len();
     // 1) Check split across carry + buf
     if carry_len > 0 {
diff --git a/src/ecsrp5.rs b/src/ecsrp5.rs
index a3f19d6..11842f4 100644
--- a/src/ecsrp5.rs
+++ b/src/ecsrp5.rs
@@ -42,7 +42,7 @@ static WEIERSTRASS_A: LazyLock<BigUint> = LazyLock::new(|| {
     .unwrap()
 });
 
-static WCURVE: LazyLock<WCurve> = LazyLock::new(WCurve::new);
+pub static WCURVE: LazyLock<WCurve> = LazyLock::new(WCurve::new);
 
 const MONT_A: u64 = 486662;
 
@@ -244,14 +244,14 @@ impl Point {
 
 // --- WCurve: Curve25519 in Weierstrass form ---
 
-struct WCurve {
+pub struct WCurve {
     g: Point,
     conversion_from_m: BigUint,
     conversion_to_m: BigUint,
 }
 
 impl WCurve {
-    fn new() -> Self {
+    pub fn new() -> Self {
         let p_val = &*P;
         let mont_a = BigUint::from(MONT_A);
         let three_inv = modinv(&BigUint::from(3u32), p_val);