diff --git a/Cargo.toml b/Cargo.toml
index d59be33..b80e1e0 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,7 +17,7 @@ unwrap_used = "deny"
 expect_used = "deny"
 
 [features]
-default = ["rq-mutex"]
+default = ["rq-mpmc"]
 smarm-trace = []
 # RFC 007: native causal profiling. Zero cost when off (cf. smarm-trace): the
 # hook in `maybe_preempt` and the resume-path fast-forward compile away; the
diff --git a/src/run_queue.rs b/src/run_queue.rs
index 16656e5..6814e8b 100644
--- a/src/run_queue.rs
+++ b/src/run_queue.rs
@@ -2,9 +2,9 @@
 //! features (no runtime dispatch — the scheduler's pop loop is the hottest
 //! code in the runtime):
 //!
-//! - `rq-mutex`   (default) — `Mutex<VecDeque>`. The control/baseline:
+//! - `rq-mutex`   — `Mutex<VecDeque>`. The control/baseline:
 //!                 strictly FIFO, trivially correct, one global lock.
-//! - `rq-mpmc`    — a single hand-rolled Vyukov bounded MPMC ring (per-cell
+//! - `rq-mpmc`    (default) — a single hand-rolled Vyukov bounded MPMC ring (per-cell
 //!                 sequence numbers). Strict FIFO, lock-free, one hot
 //!                 enqueue/dequeue cache-line pair.
 //! - `rq-striped` — M Vyukov rings with fetch-add ticket distribution.
@@ -61,20 +61,20 @@ use std::mem::MaybeUninit;
 #[cfg(not(any(feature = "rq-mutex", feature = "rq-mpmc", feature = "rq-striped")))]
 compile_error!(
     "smarm: no run queue selected. Enable exactly one of the features \
-     `rq-mutex` (default), `rq-mpmc`, `rq-striped`."
+     `rq-mpmc` (default), `rq-mutex`, `rq-striped`."
 );
 #[cfg(all(feature = "rq-mutex", feature = "rq-mpmc"))]
 compile_error!(
     "smarm: features `rq-mutex` and `rq-mpmc` are mutually exclusive \
-     (use --no-default-features to drop the default `rq-mutex`)."
+     (use --no-default-features to drop the default `rq-mpmc`)."
 );
 #[cfg(all(feature = "rq-mutex", feature = "rq-striped"))]
-compile_error!(
-    "smarm: features `rq-mutex` and `rq-striped` are mutually exclusive \
-     (use --no-default-features to drop the default `rq-mutex`)."
-);
+compile_error!("smarm: features `rq-mutex` and `rq-striped` are mutually exclusive.");
 #[cfg(all(feature = "rq-mpmc", feature = "rq-striped"))]
-compile_error!("smarm: features `rq-mpmc` and `rq-striped` are mutually exclusive.");
+compile_error!(
+    "smarm: features `rq-mpmc` and `rq-striped` are mutually exclusive \
+     (use --no-default-features to drop the default `rq-mpmc`)."
+);
 
 #[cfg(feature = "rq-mutex")]
 pub(crate) type RunQueue = MutexQueue;