diff --git a/Cargo.lock b/Cargo.lock
index 3281c61..8f391e2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -131,6 +131,21 @@ version = "1.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f2032f911046de80f0a198e0901378627c33f59ea0ac00e363d481118bd70a53"
 
+[[package]]
+name = "bit-set"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "08807e080ed7f9d5433fa9b275196cfc35414f66a0c79d864dc51a0d825231a3"
+dependencies = [
+ "bit-vec",
+]
+
+[[package]]
+name = "bit-vec"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5e764a1d40d510daf35e07be9eb06e75770908c27d411ee6c92109c9840eaaf7"
+
 [[package]]
 name = "bitflags"
 version = "1.3.2"
@@ -455,6 +470,12 @@ version = "2.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "da7c62ceae207dd37ea5b845da6a0696c799f85e97da1ab5b7910be3c1c80223"
 
+[[package]]
+name = "fnv"
+version = "1.0.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3f9eec918d3f24069decb9af1554cad7c880e2da24a9afd88aca000531ab82c1"
+
 [[package]]
 name = "foldhash"
 version = "0.2.0"
@@ -528,6 +549,18 @@ dependencies = [
  "slab",
 ]
 
+[[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 = "0.4.3"
@@ -536,7 +569,7 @@ checksum = "300e883d756b2e4ec94e02791f39b04b522276138852cfc41d9fb7e904106099"
 dependencies = [
  "cfg-if",
  "libc",
- "r-efi",
+ "r-efi 6.0.0",
 ]
 
 [[package]]
@@ -660,6 +693,7 @@ dependencies = [
  "json-patch",
  "linkme",
  "procfs",
+ "proptest",
  "ratatui",
  "regex",
  "rstest",
@@ -1087,6 +1121,15 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4a6394b9e965e73d0a289ee54f589087e2c676aedf60885baf52c76b771e4958"
 
+[[package]]
+name = "ppv-lite86"
+version = "0.2.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85eae3c4ed2f50dcfe72643da4befc30deadb458a9b590d720cde2f2b1e97da9"
+dependencies = [
+ "zerocopy",
+]
+
 [[package]]
 name = "proc-macro-crate"
 version = "3.5.0"
@@ -1126,6 +1169,31 @@ dependencies = [
  "hex",
 ]
 
+[[package]]
+name = "proptest"
+version = "1.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4b45fcc2344c680f5025fe57779faef368840d0bd1f42f216291f0dc4ace4744"
+dependencies = [
+ "bit-set",
+ "bit-vec",
+ "bitflags 2.13.2",
+ "num-traits",
+ "rand 0.9.5",
+ "rand_chacha 0.9.0",
+ "rand_xorshift 0.4.0",
+ "regex-syntax",
+ "rusty-fork",
+ "tempfile",
+ "unarray",
+]
+
+[[package]]
+name = "quick-error"
+version = "1.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a1d01941d82fa2ab50be1e79e6714289dd7cde78eba4c074bc5a4374f650dfe0"
+
 [[package]]
 name = "quote"
 version = "1.0.47"
@@ -1135,6 +1203,12 @@ 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"
@@ -1149,17 +1223,27 @@ checksum = "6d71dacdc3c88c1fde3885a3be3fbab9f35724e6ce99467f7d9c5026132184ca"
 dependencies = [
  "autocfg 0.1.8",
  "libc",
- "rand_chacha",
+ "rand_chacha 0.1.1",
  "rand_core 0.4.3",
  "rand_hc",
  "rand_isaac",
  "rand_jitter",
  "rand_os",
  "rand_pcg",
- "rand_xorshift",
+ "rand_xorshift 0.1.1",
  "winapi",
 ]
 
+[[package]]
+name = "rand"
+version = "0.9.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b9ef1d0d795eb7d84685bca4f72f3649f064e6641543d3a8c415898726a57b41"
+dependencies = [
+ "rand_chacha 0.9.0",
+ "rand_core 0.9.5",
+]
+
 [[package]]
 name = "rand_chacha"
 version = "0.1.1"
@@ -1170,6 +1254,16 @@ dependencies = [
  "rand_core 0.3.2",
 ]
 
+[[package]]
+name = "rand_chacha"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d3022b5f1df60f26e1ffddd6c66e8aa15de382ae63b3a0c1bfc0e4d3e3f325cb"
+dependencies = [
+ "ppv-lite86",
+ "rand_core 0.9.5",
+]
+
 [[package]]
 name = "rand_core"
 version = "0.3.2"
@@ -1185,6 +1279,15 @@ version = "0.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0e5937858e6fd18cd595d558f90bb5de3b72ae23f9e3763af0e805949b04ef60"
 
+[[package]]
+name = "rand_core"
+version = "0.9.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "76afc826de14238e6e8c374ddcc1fa19e374fd8dd986b0d2af0d02377261d83c"
+dependencies = [
+ "getrandom 0.3.4",
+]
+
 [[package]]
 name = "rand_hc"
 version = "0.1.0"
@@ -1247,6 +1350,15 @@ dependencies = [
  "rand_core 0.3.2",
 ]
 
+[[package]]
+name = "rand_xorshift"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "513962919efc330f829edb2535844d1b912b0fbe2ca165d613e4e8788bb05a5a"
+dependencies = [
+ "rand_core 0.9.5",
+]
+
 [[package]]
 name = "ratatui"
 version = "0.30.2"
@@ -1423,6 +1535,18 @@ version = "1.0.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf54715a573b99ac80df0bc206da022bcd442c974952c7b9720069370852e21f"
 
+[[package]]
+name = "rusty-fork"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cc6bf79ff24e648f6da1f8d1f011e9cac26491b619e6b9280f2b47f1774e6ee2"
+dependencies = [
+ "fnv",
+ "quick-error",
+ "tempfile",
+ "wait-timeout",
+]
+
 [[package]]
 name = "ryu"
 version = "1.0.23"
@@ -1570,7 +1694,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "49d57902bb128e5e38b5218d3681215ae3e322d99f65d5420e9849730d2ea372"
 dependencies = [
  "num",
- "rand",
+ "rand 0.6.5",
 ]
 
 [[package]]
@@ -1629,7 +1753,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "32497e9a4c7b38532efcdebeef879707aa9f794296a4f0244f6f69e9bc8574bd"
 dependencies = [
  "fastrand",
- "getrandom",
+ "getrandom 0.4.3",
  "once_cell",
  "rustix",
  "windows-sys",
@@ -1879,6 +2003,12 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "unarray"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eaea85b334db583fe3274d12b4cd1880032beab409c0d774be044d4480ab9a94"
+
 [[package]]
 name = "unicode-ident"
 version = "1.0.26"
@@ -1952,12 +2082,30 @@ dependencies = [
  "pkg-config",
 ]
 
+[[package]]
+name = "wait-timeout"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09ac3b126d3914f9849036f826e054cbabdc8519970b8998ddaf3b5bd3c65f11"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "wasi"
 version = "0.11.1+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ccf3ec651a847eb01de73ccad15eb7d99f80485de043efb2f370cd654f4ea44b"
 
+[[package]]
+name = "wasip2"
+version = "1.0.4+wasi-0.2.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b67efb37e106e55ce722a510d6b5f9c17f083e5fc79afc2badeb12cc313d9487"
+dependencies = [
+ "wit-bindgen",
+]
+
 [[package]]
 name = "wasm-bindgen"
 version = "0.2.129"
@@ -2058,6 +2206,12 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "wit-bindgen"
+version = "0.57.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ebf944e87a7c253233ad6766e082e3cd714b5d03812acc24c318f549614536e"
+
 [[package]]
 name = "zbus"
 version = "5.12.0"
@@ -2114,6 +2268,26 @@ dependencies = [
  "zvariant",
 ]
 
+[[package]]
+name = "zerocopy"
+version = "0.8.61"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "879fb705ce98c32e41ebdb970fbe1204f8492423b314c6ab0354c3e7b5542866"
+dependencies = [
+ "zerocopy-derive",
+]
+
+[[package]]
+name = "zerocopy-derive"
+version = "0.8.61"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "708882a28301d604fa039cc7727607a98d04c4b86dc76ec9cc683f805d709759"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.119",
+]
+
 [[package]]
 name = "zmij"
 version = "1.0.23"
diff --git a/Cargo.toml b/Cargo.toml
index 945f6d4..2c82a4d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -101,3 +101,4 @@ rstest = "0.26"
 tempfile = "3"
 test-log = { version = "0.2", features = ["trace"] }
 tokio = { version = "1", features = ["test-util"] }
+proptest = "1"
diff --git a/src/backends/qemu/helpers.rs b/src/backends/qemu/helpers.rs
index eda816a..1b120f6 100644
--- a/src/backends/qemu/helpers.rs
+++ b/src/backends/qemu/helpers.rs
@@ -320,44 +320,108 @@ pub fn next_qemu_iothread_id(existing: &[String]) -> String {
 
 #[cfg(test)]
 mod tests {
+    use proptest::prelude::*;
+
     use super::*;
 
-    /// Test that vQ round-robin mapping spreads queues across IOThreads
-    /// as evenly as possible.
+    proptest! {
+        /// Test that vQ round-robin mapping spreads queues across IOThreads
+        /// as evenly as possible.
+        #[test]
+        fn test_qemu_round_robin_partitions_queues(
+            ids in prop::collection::vec("[a-z]{1,4}", 0..8),
+            vq_count in 0u16..128,
+        ) {
+            // We run a mapping on arbitrary IOThread ids and number of queues.
+            let mapping = round_robin_vq_mapping(&ids, vq_count);
+            if ids.is_empty() || vq_count == 0 {
+                prop_assert!(mapping.is_empty());
+                return Ok(());
+            }
+
+            // Check every queue has been assigned once.
+            prop_assert_eq!(mapping.len(), ids.len());
+            let mut seen = vec![false; usize::from(vq_count)];
+            for (idx, entry) in mapping.iter().enumerate() {
+                prop_assert_eq!(&entry.iothread, &ids[idx]);
+                for &vq in &entry.vqs {
+                    prop_assert_eq!(usize::from(vq) % ids.len(), idx);
+                    prop_assert!(!seen[usize::from(vq)]);
+                    seen[usize::from(vq)] = true;
+                }
+            }
+            prop_assert!(seen.into_iter().all(|present| present));
+
+            // Check queues are evenly distributed.
+            let sizes: Vec<usize> = mapping.iter().map(|entry| entry.vqs.len()).collect();
+            let min = sizes.iter().copied().min().unwrap();
+            let max = sizes.iter().copied().max().unwrap();
+            prop_assert!(max - min <= 1);
+        }
+
+        /// Ensure the next IOThread to have a queue assigned is the one with
+        /// the lowest id.
+        #[test]
+        fn test_qemu_next_id_is_the_lowest_missing_iot(
+            // IOThreads with assigned queues, these are excluded from the search.
+            present in prop::collection::btree_set(0u32..1024, 0..32),
+        ) {
+            let ids: Vec<String> = present.iter().map(|n| format!("iot{n}")).collect();
+            // Find the thread with the lowest id.
+            let expected = (0..1024).find(|n| !present.contains(n)).unwrap();
+            prop_assert_eq!(next_qemu_iothread_id(&ids), format!("iot{expected}"));
+        }
+    }
+
+    /// Test that managed `iotN` threads are kept in id order and other ids are
+    /// dropped.
     #[test]
-    fn round_robin_distributes_evenly() {
-        let ids = vec!["iot0".to_string(), "iot1".to_string(), "iot2".to_string()];
-        let mapping = round_robin_vq_mapping(&ids, 7);
-        let counts: Vec<usize> = mapping.iter().map(|m| m.vqs.len()).collect();
-        assert_eq!(counts, vec![3, 2, 2]);
-        assert_eq!(mapping[0].vqs, vec![0, 3, 6]);
-        assert_eq!(mapping[1].vqs, vec![1, 4]);
-        assert_eq!(mapping[2].vqs, vec![2, 5]);
+    fn test_qemu_topology_keeps_managed_threads_in_id_order() {
+        let body = r#"
+qemu_iothread_info{id="iot1",tid="124"} 1
+qemu_iothread_info{id="dirtybitmap",tid="999"} 1
+qemu_iothread_info{id="iot0",tid="123"} 1
+"#;
+        let topo = QemuTopology::new(body);
+        assert_eq!(topo.iothreads, vec!["iot0", "iot1"]);
+        assert_eq!(topo.iothread_tids.get("iot0"), Some(&123));
+        assert_eq!(topo.iothread_tids.get("iot1"), Some(&124));
+        assert_eq!(topo.iothread_tids.len(), 2);
     }
 
-    /// Test that `next_qemu_iothread_id` fills the lowest missing
-    /// `iotN` id.
+    /// Test that `thread_id` and `path` are accepted in place of `tid` and
+    /// `device`.
     #[test]
-    fn next_id_fills_gaps_in_order() {
-        let ids = vec!["iot0".to_string(), "iot2".to_string()];
-        assert_eq!(next_qemu_iothread_id(&ids), "iot1");
-        let ids = vec!["iot0".to_string(), "iot1".to_string()];
-        assert_eq!(next_qemu_iothread_id(&ids), "iot2");
+    fn test_qemu_topology_accepts_label_aliases() {
+        let body = r#"
+qemu_iothread_info{id="iot0",thread_id="321"} 1
+qemu_virtio_scsi_num_queues{path="/machine/peripheral/scsi0"} 4
+"#;
+        let topo = QemuTopology::new(body);
+        assert_eq!(topo.iothreads, vec!["iot0"]);
+        assert_eq!(topo.iothread_tids.get("iot0"), Some(&321));
+        assert_eq!(topo.device_path, "/machine/peripheral/scsi0");
+        assert_eq!(topo.vq_count, 4);
     }
 
-    /// Test that prometheus scrape text yields IOThread ids, TIDs, and
-    /// the virtio-scsi device path.
+    /// Test that the first device wins, noise lines are ignored, and a later
+    /// thread is kept.
+    // TODO make sure this is intended
     #[test]
-    fn topology_parses_prometheus_body() {
-        let body = r#"# HELP foo
-qemu_iothread_info{id="iot0",tid="123"} 1
-qemu_iothread_info{id="iot1",tid="124"} 1
-qemu_iothread_info{id="dirtybitmap",tid="999"} 1
+    fn test_qemu_topology_keeps_the_first_device_and_later_threads() {
+        let body = r#"
+# HELP foo
+not a metric
+qemu_virtio_scsi_num_queues{device=""} 3
+qemu_iothread_info{id="iot7",tid="nope"} 1
 qemu_virtio_scsi_num_queues{device="/machine/peripheral/scsi0"} 4
+qemu_iothread_info{id="iot0",tid="123"} 1
+qemu_virtio_scsi_num_queues{device="/machine/peripheral/scsi1"} 99
 "#;
         let topo = QemuTopology::new(body);
-        assert_eq!(topo.iothreads, vec!["iot0", "iot1"]);
+        assert_eq!(topo.iothreads, vec!["iot0"]);
         assert_eq!(topo.iothread_tids.get("iot0"), Some(&123));
+        assert_eq!(topo.iothread_tids.len(), 1);
         assert_eq!(topo.device_path, "/machine/peripheral/scsi0");
         assert_eq!(topo.vq_count, 4);
         assert!(topo.vq_inflight.is_empty());