expose delivery rate in Stats

Author: ghedo

include/quiche.h

@@ -313,8 +313,11 @@ typedef struct {
     // The estimated round-trip time of the connection (in nanoseconds).
     uint64_t rtt;
 
-    // The size in bytes of the connection's congestion window.
+    // The size of the connection's congestion window in bytes.
     size_t cwnd;
+
+    // The estimated data delivery rate in bytes/s.
+    uint64_t delivery_rate;
 } quiche_stats;
 
 // Collects and returns statistics about the connection.

src/ffi.rs

@@ -624,6 +624,7 @@ pub struct Stats {
     pub lost: usize,
     pub rtt: u64,
     pub cwnd: usize,
+    pub delivery_rate: u64,
 }
 
 #[no_mangle]
@@ -635,6 +636,7 @@ pub extern fn quiche_conn_stats(conn: &Connection, out: &mut Stats) {
     out.lost = stats.lost;
     out.rtt = stats.rtt.as_nanos() as u64;
     out.cwnd = stats.cwnd;
+    out.delivery_rate = stats.delivery_rate as u64;
 }
 
 #[no_mangle]

src/lib.rs

@@ -2651,6 +2651,7 @@ impl Connection {
             lost: self.recovery.lost_count,
             cwnd: self.recovery.cc.cwnd(),
             rtt: self.recovery.rtt(),
+            delivery_rate: self.recovery.delivery_rate(),
         }
     }
 
@@ -3154,16 +3155,24 @@ pub struct Stats {
     /// The estimated round-trip time of the connection.
     pub rtt: time::Duration,
 
-    /// The size in bytes of the connection's congestion window.
+    /// The size of the connection's congestion window in bytes.
     pub cwnd: usize,
+
+    /// The estimated data delivery rate in bytes/s.
+    pub delivery_rate: f64,
 }
 
 impl std::fmt::Debug for Stats {
     fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
         write!(
             f,
-            "recv={} sent={} lost={} rtt={:?} cwnd={}",
-            self.recv, self.sent, self.lost, self.rtt, self.cwnd
+            "recv={} sent={} lost={} rtt={:?} cwnd={} delivery_rate={}",
+            self.recv,
+            self.sent,
+            self.lost,
+            self.rtt,
+            self.cwnd,
+            self.delivery_rate
         )
     }
 }

src/recovery.rs

@@ -376,6 +376,10 @@ impl Recovery {
         self.rtt() + cmp::max(self.rttvar * 4, GRANULARITY) + self.max_ack_delay
     }
 
+    pub fn delivery_rate(&self) -> f64 {
+        self.rate_sample.delivery_rate
+    }
+
     fn update_rtt(&mut self, latest_rtt: Duration, ack_delay: Duration) {
         self.latest_rtt = latest_rtt;