Cleanup TVU code to look like its block diagram (#1737)

* Reorg TVU code to look like TVU diagram

And move channel creation into LedgerWriteStage so that it can
be used in the same was as all the other stages.

* Delete commented out code

src/ledger_write_stage.rs

@@ -8,7 +8,7 @@ use log::Level;
 use result::{Error, Result};
 use service::Service;
 use std::sync::atomic::AtomicUsize;
-use std::sync::mpsc::RecvTimeoutError;
+use std::sync::mpsc::{channel, RecvTimeoutError};
 use std::thread::{self, Builder, JoinHandle};
 use std::time::{Duration, Instant};
 use timing::duration_as_ms;
@@ -21,7 +21,7 @@ impl LedgerWriteStage {
     pub fn write(
         ledger_writer: Option<&mut LedgerWriter>,
         entry_receiver: &EntryReceiver,
-        forwarder: &Option<EntrySender>,
+        entry_sender: &EntrySender,
     ) -> Result<()> {
         let mut ventries = Vec::new();
         let mut received_entries = entry_receiver.recv_timeout(Duration::new(1, 0))?;
@@ -44,10 +44,8 @@ impl LedgerWriteStage {
         }
 
         inc_new_counter_info!("ledger_writer_stage-entries_received", num_new_entries);
-        if let Some(forwarder) = forwarder {
         for entries in ventries {
-                forwarder.send(entries)?;
-            }
+            entry_sender.send(entries)?;
         }
         inc_new_counter_info!(
             "ledger_writer_stage-time_ms",
@@ -56,17 +54,15 @@ impl LedgerWriteStage {
         Ok(())
     }
 
-    pub fn new(
-        ledger_path: Option<&str>,
-        entry_receiver: EntryReceiver,
-        forwarder: Option<EntrySender>,
-    ) -> Self {
+    pub fn new(ledger_path: Option<&str>, entry_receiver: EntryReceiver) -> (Self, EntryReceiver) {
         let mut ledger_writer = ledger_path.map(|p| LedgerWriter::open(p, false).unwrap());
 
+        let (entry_sender, entry_forwarder) = channel();
         let write_thread = Builder::new()
             .name("solana-ledger-writer".to_string())
             .spawn(move || loop {
-                if let Err(e) = Self::write(ledger_writer.as_mut(), &entry_receiver, &forwarder) {
+                if let Err(e) = Self::write(ledger_writer.as_mut(), &entry_receiver, &entry_sender)
+                {
                     match e {
                         Error::RecvTimeoutError(RecvTimeoutError::Disconnected) => {
                             break;
@@ -83,7 +79,7 @@ impl LedgerWriteStage {
                 };
             }).unwrap();
 
-        LedgerWriteStage { write_thread }
+        (LedgerWriteStage { write_thread }, entry_forwarder)
     }
 }
 

src/tpu.rs

@@ -12,7 +12,6 @@ use service::Service;
 use sigverify_stage::SigVerifyStage;
 use std::net::UdpSocket;
 use std::sync::atomic::{AtomicBool, Ordering};
-use std::sync::mpsc::channel;
 use std::sync::mpsc::Receiver;
 use std::sync::Arc;
 use std::thread;
@@ -54,9 +53,8 @@ impl Tpu {
             max_tick_height,
         );
 
-        let (ledger_entry_sender, entry_forwarder) = channel();
-        let ledger_write_stage =
-            LedgerWriteStage::new(Some(ledger_path), entry_receiver, Some(ledger_entry_sender));
+        let (ledger_write_stage, entry_forwarder) =
+            LedgerWriteStage::new(Some(ledger_path), entry_receiver);
 
         let tpu = Tpu {
             fetch_stage,

src/tvu.rs

@@ -21,7 +21,6 @@ use service::Service;
 use signature::Keypair;
 use std::net::UdpSocket;
 use std::sync::atomic::{AtomicBool, Ordering};
-use std::sync::mpsc::channel;
 use std::sync::{Arc, RwLock};
 use std::thread;
 use storage_stage::{StorageStage, StorageState};
@@ -90,19 +89,8 @@ impl Tvu {
             bank.leader_scheduler.clone(),
         );
 
-        let (storage_entry_sender, storage_entry_receiver) = channel();
-        let storage_state = StorageState::new();
-        let storage_stage = StorageStage::new(
-            &storage_state,
-            storage_entry_receiver,
-            ledger_path,
-            keypair.clone(),
-            exit.clone(),
-            entry_height,
-        );
-
         let (replicate_stage, ledger_entry_receiver) = ReplicateStage::new(
-            keypair,
+            keypair.clone(),
             vote_account_keypair,
             bank.clone(),
             cluster_info,
@@ -111,10 +99,17 @@ impl Tvu {
             entry_height,
         );
 
-        let ledger_write_stage = LedgerWriteStage::new(
+        let (ledger_write_stage, storage_entry_receiver) =
+            LedgerWriteStage::new(ledger_path, ledger_entry_receiver);
+
+        let storage_state = StorageState::new();
+        let storage_stage = StorageStage::new(
+            &storage_state,
+            storage_entry_receiver,
             ledger_path,
-            ledger_entry_receiver,
-            Some(storage_entry_sender),
+            keypair,
+            exit.clone(),
+            entry_height,
         );
 
         Tvu {