Remove unneeded timeout in turbine retransmit stage (#4335)

turbine/src/retransmit_stage.rs

@@ -4,7 +4,7 @@
 use {
     crate::cluster_nodes::{self, ClusterNodes, ClusterNodesCache, Error, MAX_NUM_TURBINE_HOPS},
     bytes::Bytes,
-    crossbeam_channel::{Receiver, RecvTimeoutError},
+    crossbeam_channel::{Receiver, RecvError},
     lru::LruCache,
     rand::Rng,
     rayon::{prelude::*, ThreadPool, ThreadPoolBuilder},
@@ -193,10 +193,12 @@ fn retransmit(
     max_slots: &MaxSlots,
     rpc_subscriptions: Option<&RpcSubscriptions>,
     slot_status_notifier: Option<&SlotStatusNotifier>,
-) -> Result<(), RecvTimeoutError> {
-    const RECV_TIMEOUT: Duration = Duration::from_secs(1);
-    let mut shreds = shreds_receiver.recv_timeout(RECV_TIMEOUT)?;
+) -> Result<(), RecvError> {
+    // wait for something on the channel
+    let mut shreds = shreds_receiver.recv()?;
+    // now the batch has started
     let mut timer_start = Measure::start("retransmit");
+    // drain the channel until it is empty to form a batch
     shreds.extend(shreds_receiver.try_iter().flatten());
     stats.num_shreds += shreds.len();
     stats.total_batches += 1;
@@ -392,7 +394,9 @@ pub fn retransmitter(
     );
     let mut rng = rand::thread_rng();
     let mut shred_deduper = ShredDeduper::new(&mut rng, DEDUPER_NUM_BITS);
+
     let mut stats = RetransmitStats::new(Instant::now());
+
     #[allow(clippy::manual_clamp)]
     let num_threads = get_thread_count().min(8).max(sockets.len());
     let thread_pool = ThreadPoolBuilder::new()
@@ -402,8 +406,8 @@ pub fn retransmitter(
         .unwrap();
     Builder::new()
         .name("solRetransmittr".to_string())
-        .spawn(move || loop {
-            match retransmit(
+        .spawn(move || {
+            while retransmit(
                 &thread_pool,
                 &bank_forks,
                 &leader_schedule_cache,
@@ -417,11 +421,9 @@ pub fn retransmitter(
                 &max_slots,
                 rpc_subscriptions.as_deref(),
                 slot_status_notifier.as_ref(),
-            ) {
-                Ok(()) => (),
-                Err(RecvTimeoutError::Timeout) => (),
-                Err(RecvTimeoutError::Disconnected) => break,
-            }
+            )
+            .is_ok()
+            {}
         })
         .unwrap()
 }