bench tor round trips

2 files changed, 51 insertions, 3 deletions

diff --git a/docs/development.md b/docs/development.md
index 2ed15f6..519d64c 100644
--- a/docs/development.md
+++ b/docs/development.md
@@ -22,7 +22,7 @@ messages, `document/bench.rs`), the remakes' replay (`remake/bench.rs`), and wha
 passing changes on costs over the simulated network (`simtest/bench.rs`: messages and
 bytes per write by kind, propagation delays, for a full mesh, a writer behind NAT, two
 transports, partial meshes of 50 and 100 nodes, lossy links (with delays at random,
-and with Mycelium's round trips, each link its own), a member away for a while, and
+and with Mycelium's round trips, each link its own; and Tor's, with some slow circuits), a member away for a while, and
 members joining during the writes; several minutes, or one scenario alone
 with `BENCH_SCENARIO`, part of its name: `BENCH_SCENARIO=NAT`; all at once with
 `BENCH_PARALLEL=1`, faster on many cores, though sharing them makes delays come out
diff --git a/src/simtest/bench.rs b/src/simtest/bench.rs
index 82c8985..1d6d411 100644
--- a/src/simtest/bench.rs
+++ b/src/simtest/bench.rs
@@ -63,6 +63,9 @@ struct Scenario {
     /// registration reached them, and their trees with them. Their catching up counts
     /// in the messages, but not in the delays (`swarm::stats`: not until caught up).
     joining: usize,
+    /// The first wait for a sync answer, if not `SYNC_REPLY_TIMEOUT`: longer where round
+    /// trips take seconds, as Tor's transport asks for (`Transport::sync_reply_timeout`).
+    reply_timeout: Option<Duration>,
 }
 
 fn sim_only(_: usize) -> &'static [&'static str] {
@@ -127,6 +130,31 @@ fn mycelium_like(sim: &Sim, ids: &[String]) {
     }
 }
 
+/// Each link a round trip of its own, as over Tor: 250 to 400 ms, each message within a
+/// fifth of its link's; one link in ten through a slow circuit, 1 to 3 s. Nothing lost
+/// (Tor carries streams reliably). The simulated net can't make one link slow for a
+/// while only, so the circuits that are slow at times are slow throughout here. With a
+/// first wait for answers of 5 s, as Tor's transport waits longer (30 s in production).
+fn tor_like(sim: &Sim, ids: &[String]) {
+    let mut rng = crate::testrand::Rng::new(9);
+    for (i, from) in ids.iter().enumerate() {
+        for to in &ids[i + 1..] {
+            let rtt_ms = if rng.chance(0.1) {
+                1000.0 + rng.next_f64() * 2000.0
+            } else {
+                250.0 + rng.next_f64() * 150.0
+            };
+            let half = Duration::from_secs_f64(rtt_ms / 2.0 / 1000.0);
+            let link = LinkParams {
+                delay: (half * 4 / 5, half * 6 / 5),
+                ..LinkParams::default()
+            };
+            sim.net.set_link(from, to, link.clone());
+            sim.net.set_link(to, from, link);
+        }
+    }
+}
+
 const SCENARIOS: &[Scenario] = &[
     Scenario {
         name: "full mesh, 13 nodes",
@@ -136,6 +164,7 @@ const SCENARIOS: &[Scenario] = &[
         writer: 1,
         away: None,
         joining: 0,
+        reply_timeout: None,
     },
     Scenario {
         name: "writer behind NAT (one link), 13 nodes",
@@ -145,6 +174,7 @@ const SCENARIOS: &[Scenario] = &[
         writer: 1,
         away: None,
         joining: 0,
+        reply_timeout: None,
     },
     Scenario {
         name: "two transports, 3 bridges, 30 nodes",
@@ -154,6 +184,7 @@ const SCENARIOS: &[Scenario] = &[
         writer: 5,
         away: None,
         joining: 0,
+        reply_timeout: None,
     },
     Scenario {
         name: "partial mesh, 50 nodes",
@@ -163,6 +194,7 @@ const SCENARIOS: &[Scenario] = &[
         writer: 1,
         away: None,
         joining: 0,
+        reply_timeout: None,
     },
     Scenario {
         name: "partial mesh, lossy and slow links, 50 nodes",
@@ -172,6 +204,7 @@ const SCENARIOS: &[Scenario] = &[
         writer: 1,
         away: None,
         joining: 0,
+        reply_timeout: None,
     },
     Scenario {
         name: "partial mesh, 100 nodes",
@@ -181,6 +214,7 @@ const SCENARIOS: &[Scenario] = &[
         writer: 1,
         away: None,
         joining: 0,
+        reply_timeout: None,
     },
     Scenario {
         name: "partial mesh, a member away for 10 s, 50 nodes",
@@ -190,6 +224,7 @@ const SCENARIOS: &[Scenario] = &[
         writer: 1,
         away: Some(3),
         joining: 0,
+        reply_timeout: None,
     },
     Scenario {
         name: "partial mesh, 5 members joining during each workload, 50 nodes",
@@ -199,6 +234,7 @@ const SCENARIOS: &[Scenario] = &[
         writer: 1,
         away: None,
         joining: 5,
+        reply_timeout: None,
     },
     // Last, so the others keep their seeds.
     Scenario {
@@ -209,6 +245,17 @@ const SCENARIOS: &[Scenario] = &[
         writer: 1,
         away: None,
         joining: 0,
+        reply_timeout: None,
+    },
+    Scenario {
+        name: "partial mesh, Tor's round trips, 50 nodes",
+        nodes: 50,
+        on: sim_only,
+        net: tor_like,
+        writer: 1,
+        away: None,
+        joining: 0,
+        reply_timeout: Some(Duration::from_secs(5)),
     },
 ];
 
@@ -378,8 +425,9 @@ async fn run(seed: u64, scenario: &'static Scenario) -> String {
     let sim = Sim::with_identity(seed);
     let ids: Vec<String> = (0..scenario.nodes).map(|i| format!("n{i:03}")).collect();
     (scenario.net)(&sim, &ids);
-    let timing = |config: &mut crate::node::NodeConfig| {
-        config.timing = Timing::new(KEEPALIVE, SYNC_REPLY_TIMEOUT, DELIVERY_LIMIT);
+    let reply_timeout = scenario.reply_timeout.unwrap_or(SYNC_REPLY_TIMEOUT);
+    let timing = move |config: &mut crate::node::NodeConfig| {
+        config.timing = Timing::new(KEEPALIVE, reply_timeout, DELIVERY_LIMIT);
         // As in production (`--neighbours`).
         config.neighbours_k = 12;
     };