Have 3MB test use slow start

Author: WesleyRosenblum

quic/s2n-quic-core/tests/recovery/simulation.rs

@@ -5,7 +5,7 @@ use s2n_quic_core::{
     packet::number::PacketNumberSpace,
     path::MINIMUM_MTU,
     recovery::{CongestionController, CubicCongestionController, RTTEstimator},
-    time::{Clock, NoopClock},
+    time::{Clock, NoopClock, Timestamp},
 };
 use std::{
     env,
@@ -22,10 +22,10 @@ fn slow_start_unlimited_test() {
 }
 
 #[test]
-fn five_mb_loss_test() {
+fn loss_at_3mb_test() {
     let cc = CubicCongestionController::new(MINIMUM_MTU);
 
-    five_mb_loss(cc, 150).finish();
+    loss_at_3mb(cc, 135).finish();
 }
 
 #[derive(Debug)]
@@ -170,29 +170,20 @@ fn slow_start_unlimited<CC: CongestionController>(
     }
 }
 
-/// Simulates a network that experienced loss at a 5MB congestion window
-fn five_mb_loss<CC: CongestionController>(
+/// Simulates a network that experienced loss at a 3MB congestion window
+fn loss_at_3mb<CC: CongestionController>(
     mut congestion_controller: CC,
     num_rounds: usize,
 ) -> Simulation {
     let time_zero = NoopClock.get_time();
     let mut rtt_estimator = RTTEstimator::new(Duration::from_millis(0));
     let mut rounds = Vec::with_capacity(num_rounds);
 
-    // Ensure the congestion window is always fully utilized
+    // Ensure the congestion window is fully utilized
     congestion_controller.on_packet_sent(time_zero, u32::MAX as usize);
 
-    // Start the window at 5MB
-    congestion_controller.on_packet_ack(time_zero, 5_000_000, &rtt_estimator, time_zero);
-
-    // Exit slow start
-    congestion_controller.on_congestion_event(time_zero);
-
     let mut ack_receive_time = time_zero + Duration::from_millis(1);
 
-    // Exit recovery
-    congestion_controller.on_packet_ack(ack_receive_time, 1, &rtt_estimator, ack_receive_time);
-
     // Update the rtt with 200 ms
     rtt_estimator.update_rtt(
         Duration::from_millis(0),
@@ -202,34 +193,61 @@ fn five_mb_loss<CC: CongestionController>(
         PacketNumberSpace::ApplicationData,
     );
 
-    for round in 0..num_rounds {
+    let mut slow_start_round = 0;
+
+    while congestion_controller.congestion_window() < 3_000_000 && slow_start_round < num_rounds {
+        ack_receive_time += Duration::from_millis(200);
+
+        // Ack the full congestion window
+        ack_cwnd(&mut congestion_controller, &rtt_estimator, ack_receive_time);
+
+        rounds.push(Round {
+            number: slow_start_round,
+            cwnd: congestion_controller.congestion_window(),
+        });
+
+        slow_start_round += 1;
+    }
+
+    // Lose a packet to exit slow start
+    congestion_controller.on_packets_lost(MINIMUM_MTU as u32, false, ack_receive_time);
+
+    for round in slow_start_round..num_rounds {
         rounds.push(Round {
             number: round,
             cwnd: congestion_controller.congestion_window(),
         });
 
         ack_receive_time += Duration::from_millis(200);
 
-        let mut cwnd = congestion_controller.congestion_window();
-
         // Ack the full congestion window
-        while cwnd > MINIMUM_MTU as u32 {
-            congestion_controller.on_packet_ack(
-                ack_receive_time,
-                MINIMUM_MTU as usize,
-                &rtt_estimator,
-                ack_receive_time,
-            );
-            cwnd -= MINIMUM_MTU as u32;
-            // Ensure the congestion window is always fully utilized by sending a packet the
-            // same size as the one that we just acked.
-            congestion_controller.on_packet_sent(ack_receive_time, MINIMUM_MTU as usize);
-        }
+        ack_cwnd(&mut congestion_controller, &rtt_estimator, ack_receive_time);
     }
 
     Simulation {
-        name: "5MB Loss",
+        name: "Loss at 3MB",
         cc: core::any::type_name::<CC>(),
         rounds,
     }
 }
+
+/// Acknowledge a full congestion window of packets
+fn ack_cwnd<CC: CongestionController>(
+    congestion_controller: &mut CC,
+    rtt_estimator: &RTTEstimator,
+    timestamp: Timestamp,
+) {
+    let mut cwnd = congestion_controller.congestion_window();
+    while cwnd >= MINIMUM_MTU as u32 {
+        congestion_controller.on_packet_ack(
+            timestamp,
+            MINIMUM_MTU as usize,
+            rtt_estimator,
+            timestamp,
+        );
+        cwnd -= MINIMUM_MTU as u32;
+        // Ensure the congestion window is always fully utilized by sending a packet the
+        // same size as the one that we just acked.
+        congestion_controller.on_packet_sent(timestamp, MINIMUM_MTU as usize);
+    }
+}

quic/s2n-quic-core/tests/recovery/snapshots/recovery_simulation__Lossat3MB-CubicCongestionController.snap

@@ -0,0 +1,145 @@
+---
+source: quic/s2n-quic-core/tests/recovery/simulation.rs
+expression: self
+---
+Simulation {
+    name: "Loss at 3MB",
+    cc: "s2n_quic_core::recovery::cubic::CubicCongestionController",
+    rounds: [
+          0: cwnd: 24000,
+          1: cwnd: 48000,
+          2: cwnd: 96000,
+          3: cwnd: 192000,
+          4: cwnd: 384000,
+          5: cwnd: 768000,
+          6: cwnd: 1536000,
+          7: cwnd: 3072000,
+          8: cwnd: 2150400,
+          9: cwnd: 2177382,
+         10: cwnd: 2213988,
+         11: cwnd: 2253323,
+         12: cwnd: 2292821,
+         13: cwnd: 2331555,
+         14: cwnd: 2369174,
+         15: cwnd: 2405575,
+         16: cwnd: 2440711,
+         17: cwnd: 2474599,
+         18: cwnd: 2507254,
+         19: cwnd: 2538697,
+         20: cwnd: 2568945,
+         21: cwnd: 2598009,
+         22: cwnd: 2625973,
+         23: cwnd: 2652756,
+         24: cwnd: 2678458,
+         25: cwnd: 2703107,
+         26: cwnd: 2726659,
+         27: cwnd: 2749208,
+         28: cwnd: 2770781,
+         29: cwnd: 2791302,
+         30: cwnd: 2810877,
+         31: cwnd: 2829553,
+         32: cwnd: 2847298,
+         33: cwnd: 2864109,
+         34: cwnd: 2880066,
+         35: cwnd: 2895228,
+         36: cwnd: 2909562,
+         37: cwnd: 2923030,
+         38: cwnd: 2935720,
+         39: cwnd: 2947691,
+         40: cwnd: 2958972,
+         41: cwnd: 2969568,
+         42: cwnd: 2979367,
+         43: cwnd: 2988501,
+         44: cwnd: 2997001,
+         45: cwnd: 3004947,
+         46: cwnd: 3012326,
+         47: cwnd: 3019191,
+         48: cwnd: 3025418,
+         49: cwnd: 3031022,
+         50: cwnd: 3036145,
+         51: cwnd: 3040817,
+         52: cwnd: 3045043,
+         53: cwnd: 3048843,
+         54: cwnd: 3052340,
+         55: cwnd: 3055499,
+         56: cwnd: 3058316,
+         57: cwnd: 3060728,
+         58: cwnd: 3062569,
+         59: cwnd: 3064131,
+         60: cwnd: 3065437,
+         61: cwnd: 3066508,
+         62: cwnd: 3067369,
+         63: cwnd: 3068043,
+         64: cwnd: 3068552,
+         65: cwnd: 3068920,
+         66: cwnd: 3069169,
+         67: cwnd: 3069323,
+         68: cwnd: 3069405,
+         69: cwnd: 3069437,
+         70: cwnd: 3069443,
+         71: cwnd: 3069445,
+         72: cwnd: 3069467,
+         73: cwnd: 3069532,
+         74: cwnd: 3069662,
+         75: cwnd: 3069881,
+         76: cwnd: 3070212,
+         77: cwnd: 3070679,
+         78: cwnd: 3071302,
+         79: cwnd: 3072106,
+         80: cwnd: 3073116,
+         81: cwnd: 3074351,
+         82: cwnd: 3075835,
+         83: cwnd: 3077594,
+         84: cwnd: 3079647,
+         85: cwnd: 3082020,
+         86: cwnd: 3084663,
+         87: cwnd: 3087525,
+         88: cwnd: 3090691,
+         89: cwnd: 3094214,
+         90: cwnd: 3098152,
+         91: cwnd: 3102644,
+         92: cwnd: 3107642,
+         93: cwnd: 3113144,
+         94: cwnd: 3119216,
+         95: cwnd: 3125854,
+         96: cwnd: 3132975,
+         97: cwnd: 3140572,
+         98: cwnd: 3148783,
+         99: cwnd: 3157621,
+        100: cwnd: 3167163,
+        101: cwnd: 3177414,
+        102: cwnd: 3188382,
+        103: cwnd: 3200084,
+        104: cwnd: 3212423,
+        105: cwnd: 3225524,
+        106: cwnd: 3239428,
+        107: cwnd: 3254175,
+        108: cwnd: 3269795,
+        109: cwnd: 3286292,
+        110: cwnd: 3303594,
+        111: cwnd: 3321766,
+        112: cwnd: 3340905,
+        113: cwnd: 3361007,
+        114: cwnd: 3382120,
+        115: cwnd: 3404220,
+        116: cwnd: 3427287,
+        117: cwnd: 3451389,
+        118: cwnd: 3476581,
+        119: cwnd: 3502879,
+        120: cwnd: 3530322,
+        121: cwnd: 3558842,
+        122: cwnd: 3588507,
+        123: cwnd: 3619355,
+        124: cwnd: 3651435,
+        125: cwnd: 3684752,
+        126: cwnd: 3719332,
+        127: cwnd: 3755134,
+        128: cwnd: 3792231,
+        129: cwnd: 3830657,
+        130: cwnd: 3870442,
+        131: cwnd: 3911611,
+        132: cwnd: 3954148,
+        133: cwnd: 3998073,
+        134: cwnd: 4043424,
+    ],
+}