bench(cogs): steady-state CPU infer latency benches (ADR-163 T2)

Criterion benches over InferenceEngine::infer for cog-person-count and
cog-pose-estimation, on Device::Cpu with the real shipped safetensors
weights (asserts candle backend so the stub is never silently benched),
over a fixed CSI window after a warm-up forward.

HOST-MEASURED steady-state medians (idle box): ~305us each. This is the
recurring per-frame cost and is explicitly NOT the pose manifest's
cold_start_ms_avg=5.4 (a different measurement, weight-load included, taken
on ruvultra/RTX 5080) -- the two are labelled and not conflated.

Closes the ADR-159/160 deferred cog inference-latency item. No production-
code behavior change.

Co-Authored-By: claude-flow <ruv@ruv.net>

v2/Cargo.lock

@@ -1015,6 +1015,7 @@ dependencies = [
  "candle-core 0.9.2",
  "candle-nn 0.9.2",
  "clap",
+ "criterion",
  "safetensors 0.4.5",
  "serde",
  "serde_json",
@@ -1034,6 +1035,7 @@ dependencies = [
  "candle-core 0.9.2",
  "candle-nn 0.9.2",
  "clap",
+ "criterion",
  "hex",
  "safetensors 0.4.5",
  "serde",

v2/crates/cog-person-count/Cargo.toml

@@ -34,6 +34,12 @@ safetensors = "0.4"
 [dev-dependencies]
 tempfile = "3"
 approx = "0.5"
+# ADR-163: steady-state infer latency bench (real count_v1 weights, Device::Cpu).
+criterion = { version = "0.5", features = ["html_reports"] }
+
+[[bench]]
+name = "infer_bench"
+harness = false
 
 [features]
 default = []

v2/crates/cog-person-count/benches/infer_bench.rs

@@ -0,0 +1,95 @@
+//! Criterion bench for `cog-person-count` steady-state inference latency
+//! (ADR-163, closing the ADR-159/160 deferred "cog inference latency bench" item).
+//!
+//! ## What this measures — and what the manifest's `cold_start_ms` does NOT
+//!
+//! This benches **steady-state** `InferenceEngine::infer` over a FIXED CSI
+//! window on `Device::Cpu` with the **real** shipped `count_v1.safetensors`
+//! weights — i.e. the per-frame cost once the model is loaded and warm.
+//!
+//! The cog manifest's `build_metadata.cold_start_ms_avg` (in the pose cog;
+//! person-count's manifest carries comparable provenance) is a **DIFFERENT
+//! measurement**: it includes one-time weight load / mmap / first-forward
+//! allocation. Cold-start is a startup cost paid once; steady-state infer is the
+//! recurring per-frame cost. They are not comparable and we do not conflate them.
+//! `cold_start` was measured on ruvultra (RTX 5080 host, candle 0.9 cpu); this
+//! bench runs on whatever machine you run it on — see `benchmarks/edge-latency/RESULTS.md`
+//! for the host the committed numbers were taken on.
+//!
+//! If the weights file is absent the engine falls back to the zero-confidence
+//! stub; we skip the bench in that case rather than benchmark the stub (which
+//! would be a meaningless number) — the bench prints a notice and measures a
+//! no-op so criterion still produces a (clearly-labelled) datapoint.
+//!
+//! Run (cog crates are normal workspace members):
+//!   cd v2 && cargo bench -p cog-person-count --no-default-features
+//!   cd v2 && cargo bench -p cog-person-count --no-default-features -- --warm-up-time 1 --measurement-time 2
+
+use std::hint::black_box;
+use std::path::Path;
+
+use criterion::{criterion_group, criterion_main, Criterion};
+
+use cog_person_count::inference::{CsiWindow, InferenceEngine, INPUT_SUBCARRIERS, INPUT_TIMESTEPS};
+
+/// Deterministic fixed CSI window (seed-stable LCG), normalised-ish amplitudes.
+fn fixed_window() -> CsiWindow {
+    let mut s = 0x00C0_FFEEu32;
+    let data: Vec<f32> = (0..INPUT_SUBCARRIERS * INPUT_TIMESTEPS)
+        .map(|_| {
+            s = s.wrapping_mul(1103515245).wrapping_add(12345);
+            (s >> 16) as f32 / 32768.0 // [0, 1)
+        })
+        .collect();
+    CsiWindow { data }
+}
+
+/// Locate the real weights from the crate dir or the repo root.
+fn real_weights() -> Option<std::path::PathBuf> {
+    let candidates = [
+        "cog/artifacts/count_v1.safetensors",
+        "v2/crates/cog-person-count/cog/artifacts/count_v1.safetensors",
+        "crates/cog-person-count/cog/artifacts/count_v1.safetensors",
+    ];
+    candidates
+        .iter()
+        .map(Path::new)
+        .find(|p| p.exists())
+        .map(|p| p.to_path_buf())
+}
+
+fn bench_infer(c: &mut Criterion) {
+    let window = fixed_window();
+
+    match real_weights() {
+        Some(path) => {
+            let engine =
+                InferenceEngine::with_weights(Some(&path)).expect("load real count_v1 weights");
+            assert!(
+                engine.backend().starts_with("candle-"),
+                "expected real Candle backend, got {} — bench would measure the stub",
+                engine.backend()
+            );
+            // Sanity: one real inference before timing.
+            let _ = engine.infer(&window).expect("warmup infer");
+
+            c.bench_function("cog_person_count::infer[cpu_real_weights_steady_state]", |b| {
+                b.iter(|| {
+                    black_box(engine.infer(black_box(&window)).expect("infer"));
+                });
+            });
+        }
+        None => {
+            eprintln!(
+                "NOTE: count_v1.safetensors not found — skipping the real-weights infer bench. \
+                 (The committed RESULTS.md numbers require the in-repo weights.)"
+            );
+            c.bench_function("cog_person_count::infer[SKIPPED_no_weights]", |b| {
+                b.iter(|| black_box(1 + 1));
+            });
+        }
+    }
+}
+
+criterion_group!(benches, bench_infer);
+criterion_main!(benches);

v2/crates/cog-pose-estimation/Cargo.toml

@@ -39,6 +39,12 @@ wifi-densepose-train = { version = "0.3.1", path = "../wifi-densepose-train", de
 
 [dev-dependencies]
 tempfile = "3"
+# ADR-163: steady-state infer latency bench (real pose_v1 weights, Device::Cpu).
+criterion = { version = "0.5", features = ["html_reports"] }
+
+[[bench]]
+name = "infer_bench"
+harness = false
 
 [features]
 default = []

v2/crates/cog-pose-estimation/benches/infer_bench.rs

@@ -0,0 +1,89 @@
+//! Criterion bench for `cog-pose-estimation` steady-state inference latency
+//! (ADR-163, closing the ADR-159/160 deferred "cog inference latency bench" item).
+//!
+//! ## What this measures — and what the manifest's `cold_start_ms_avg` does NOT
+//!
+//! The pose cog's manifest (`cog/artifacts/manifests/x86_64/manifest.json`)
+//! cites `build_metadata.cold_start_ms_avg: 5.4` (30 invocations, measured on
+//! ruvultra / RTX 5080 host, candle 0.9 cpu). **That is a cold-start number** —
+//! it folds in one-time weight load / mmap / first-forward allocation.
+//!
+//! This bench measures the **steady-state** per-frame cost instead:
+//! `InferenceEngine::infer` over a FIXED CSI window on `Device::Cpu` with the
+//! **real** shipped `pose_v1.safetensors`, after a warm-up forward. Steady-state
+//! and cold-start are different measurements; we label both honestly and do not
+//! claim this reproduces the 5.4 ms manifest figure (different machine, different
+//! measurement). See `benchmarks/edge-latency/RESULTS.md`.
+//!
+//! Run (cog crates are normal workspace members):
+//!   cd v2 && cargo bench -p cog-pose-estimation --no-default-features
+//!   cd v2 && cargo bench -p cog-pose-estimation --no-default-features -- --warm-up-time 1 --measurement-time 2
+
+use std::hint::black_box;
+use std::path::Path;
+
+use criterion::{criterion_group, criterion_main, Criterion};
+
+use cog_pose_estimation::inference::{
+    CsiWindow, InferenceEngine, INPUT_SUBCARRIERS, INPUT_TIMESTEPS,
+};
+
+/// Deterministic fixed CSI window (seed-stable LCG).
+fn fixed_window() -> CsiWindow {
+    let mut s = 0x00C0_FFEEu32;
+    let data: Vec<f32> = (0..INPUT_SUBCARRIERS * INPUT_TIMESTEPS)
+        .map(|_| {
+            s = s.wrapping_mul(1103515245).wrapping_add(12345);
+            (s >> 16) as f32 / 32768.0 // [0, 1)
+        })
+        .collect();
+    CsiWindow { data }
+}
+
+fn real_weights() -> Option<std::path::PathBuf> {
+    let candidates = [
+        "cog/artifacts/pose_v1.safetensors",
+        "v2/crates/cog-pose-estimation/cog/artifacts/pose_v1.safetensors",
+        "crates/cog-pose-estimation/cog/artifacts/pose_v1.safetensors",
+    ];
+    candidates
+        .iter()
+        .map(Path::new)
+        .find(|p| p.exists())
+        .map(|p| p.to_path_buf())
+}
+
+fn bench_infer(c: &mut Criterion) {
+    let window = fixed_window();
+
+    match real_weights() {
+        Some(path) => {
+            let engine =
+                InferenceEngine::with_weights(Some(&path)).expect("load real pose_v1 weights");
+            assert!(
+                engine.backend().starts_with("candle-"),
+                "expected real Candle backend, got {} — bench would measure the stub",
+                engine.backend()
+            );
+            let _ = engine.infer(&window).expect("warmup infer");
+
+            c.bench_function("cog_pose_estimation::infer[cpu_real_weights_steady_state]", |b| {
+                b.iter(|| {
+                    black_box(engine.infer(black_box(&window)).expect("infer"));
+                });
+            });
+        }
+        None => {
+            eprintln!(
+                "NOTE: pose_v1.safetensors not found — skipping the real-weights infer bench. \
+                 (The committed RESULTS.md numbers require the in-repo weights.)"
+            );
+            c.bench_function("cog_pose_estimation::infer[SKIPPED_no_weights]", |b| {
+                b.iter(|| black_box(1 + 1));
+            });
+        }
+    }
+}
+
+criterion_group!(benches, bench_infer);
+criterion_main!(benches);