diff --git a/Cargo.toml b/Cargo.toml
index 777723e3..3c5e5c46 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -205,6 +205,18 @@ lto = "fat"
 codegen-units = 1
 strip = "debuginfo"
 
+# Iteration-speed sibling of `release`: thin LTO parallelizes the LTO
+# stage across cores instead of fat LTO's single-threaded whole-graph
+# pass — measured cold builds of the aisix binary on a 12-core host:
+# 6m37s (release) vs 2m27s (release-dev). Functionally identical output,
+# slightly less optimized — so any number that gets reported, compared
+# against a baseline, or fed into the saturation grid MUST come from
+# `--release`, never from this profile.
+[profile.release-dev]
+inherits = "release"
+lto = "thin"
+codegen-units = 16
+
 [profile.coverage]
 inherits = "dev"
 opt-level = 0
diff --git a/bench/onthebench/run-baseline.sh b/bench/onthebench/run-baseline.sh
index 53283789..8b136aef 100755
--- a/bench/onthebench/run-baseline.sh
+++ b/bench/onthebench/run-baseline.sh
@@ -27,7 +27,12 @@ BIN="$SRC/target/release/aisix"
 
 # ---- sanity -----------------------------------------------------------------
 
-[ -x "$BIN" ] || { echo "FATAL: $BIN missing - build first"; exit 1; }
+# Rebuild instead of trusting mtime: with iteration builds living in
+# target/release-dev, a stale target/release binary is silent poison —
+# meta.json would attribute the numbers to the wrong commit. A no-op
+# when the binary is already current.
+( cd "$SRC" && cargo build --locked --release --bin aisix )
+[ -x "$BIN" ] || { echo "FATAL: $BIN missing after build"; exit 1; }
 rig_sanity
 if [ "$FLAMEGRAPH" = 1 ]; then require_symbols "$BIN"; fi
 
diff --git a/bench/onthebench/run-decay.sh b/bench/onthebench/run-decay.sh
index 60244f39..b4b8c776 100755
--- a/bench/onthebench/run-decay.sh
+++ b/bench/onthebench/run-decay.sh
@@ -56,7 +56,10 @@ BIN="$SRC/target/release/aisix"
 
 # ---- sanity -----------------------------------------------------------------
 
-[ -x "$BIN" ] || { echo "FATAL: $BIN missing - build first"; exit 1; }
+# Rebuild instead of trusting mtime — same stale-binary gate as
+# run-baseline.sh; a no-op when the binary is already current.
+( cd "$SRC" && cargo build --locked --release --bin aisix )
+[ -x "$BIN" ] || { echo "FATAL: $BIN missing after build"; exit 1; }
 rig_sanity
 
 bench_init