perf: avoid lock contention in tx queue

configs/default.toml

@@ -20,6 +20,8 @@ token_contract_address = "0x2000000000000000000000000000000000000001"
 recipient_distribution_factor = 20 # 1/20 of accounts receive transfers.
 max_transfer_amount = 10
 
+batch_size = 1000 # Number of transactions to generate before pushing to queue.
+
 [rate_limiting]
 initial_ratelimit = 100 # txs/s
 

crescendo/src/bin/generate_genesis_alloc.rs

@@ -18,7 +18,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     const NUM_ACCOUNTS: u32 = 50_000;
     const MNEMONIC: &str = "test test test test test test test test test test test junk";
 
-    println!("Generating {} accounts...", NUM_ACCOUNTS);
+    println!("Generating {NUM_ACCOUNTS} accounts...");
 
     let genesis_alloc: BTreeMap<String, AccountBalance> = (0..NUM_ACCOUNTS)
         .into_par_iter()
@@ -27,17 +27,17 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
             let signer =
                 MnemonicBuilder::<English>::default().phrase(MNEMONIC).index(worker_id).unwrap().build().unwrap();
 
-            let address = secret_key_to_address(&signer.credential());
+            let address = secret_key_to_address(signer.credential());
 
-            (format!("{:?}", address), AccountBalance { balance: "0xD3C21BCECCEDA1000000".to_string() })
+            (format!("{address:?}"), AccountBalance { balance: "0xD3C21BCECCEDA1000000".to_string() })
         })
         .collect();
 
     let output_path = Path::new("genesis-alloc.json");
     let json = serde_json::to_string_pretty(&genesis_alloc)?;
     fs::write(output_path, json)?;
 
-    println!("\nSuccessfully generated {} accounts!", NUM_ACCOUNTS);
+    println!("\nSuccessfully generated {NUM_ACCOUNTS} accounts!");
     println!("Accounts saved to: {}", output_path.display());
 
     Ok(())

crescendo/src/config.rs

@@ -82,6 +82,8 @@ pub struct TxGenWorkerConfig {
     pub token_contract_address: String,
     pub recipient_distribution_factor: u32,
     pub max_transfer_amount: u64,
+
+    pub batch_size: u32,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]

crescendo/src/main.rs

@@ -4,7 +4,6 @@ use std::thread;
 use std::time::Duration;
 
 use clap::Parser;
-use core_affinity;
 use mimalloc::MiMalloc;
 
 mod config;
@@ -70,7 +69,7 @@ async fn main() {
 
     let connections_per_network_worker =
         config::get().network_worker.total_connections / worker_counts[&WorkerType::Network];
-    println!("[*] Connections per network worker: {}", connections_per_network_worker);
+    println!("[*] Connections per network worker: {connections_per_network_worker}");
 
     // TODO: Having the assign_workers function do this would be cleaner.
     let mut tx_gen_worker_id = 0;

crescendo/src/tx_queue.rs

@@ -37,25 +37,35 @@ impl TxQueue {
 pub static TX_QUEUE: std::sync::LazyLock<TxQueue> = std::sync::LazyLock::new(TxQueue::new);
 
 impl TxQueue {
-    pub fn push_tx(&self, tx: Vec<u8>) {
-        self.total_added.fetch_add(1, Ordering::Relaxed);
-        self.queue.lock().push_back(tx);
+    pub fn push_txs(&self, txs: Vec<Vec<u8>>) {
+        self.total_added.fetch_add(txs.len() as u64, Ordering::Relaxed);
+        self.queue.lock().extend(txs);
     }
 
     pub fn queue_len(&self) -> usize {
         self.queue.lock().len()
     }
 
     pub async fn pop_at_most(&self, max_count: usize) -> Option<Vec<Vec<u8>>> {
-        let mut queue = self.queue.lock();
-        let allowed = (0..queue.len().min(max_count)).take_while(|_| self.rate_limiter.try_wait().is_ok()).count();
+        // Assume the queue has sufficient items for now.
+        let allowed = (0..max_count).take_while(|_| self.rate_limiter.try_wait().is_ok()).count();
         if allowed == 0 {
             return None;
+        }
+
+        // Scope to release lock asap.
+        let drained = {
+            let mut queue = self.queue.lock();
+            let to_drain = allowed.min(queue.len());
+            if to_drain == 0 {
+                return None;
+            }
+            queue.drain(..to_drain).collect::<Vec<_>>()
         };
 
-        self.total_popped.fetch_add(allowed as u64, Ordering::Relaxed);
+        self.total_popped.fetch_add(drained.len() as u64, Ordering::Relaxed);
 
-        Some(queue.drain(..allowed).collect())
+        Some(drained)
     }
 
     pub async fn start_reporter(&self, measurement_interval: std::time::Duration) {

crescendo/src/utils.rs

@@ -13,7 +13,7 @@ pub fn increase_nofile_limit(min_limit: u64) -> io::Result<u64> {
     println!("[*] At startup, file descriptor limit:      soft = {soft}, hard = {hard}");
 
     if hard < min_limit {
-        panic!("[!] File descriptor hard limit is too low. Please increase it to at least {}.", min_limit);
+        panic!("[!] File descriptor hard limit is too low. Please increase it to at least {min_limit}.");
     }
 
     if soft != hard {
@@ -61,7 +61,7 @@ pub fn format_ranges(nums: &[usize]) -> String {
         if start == end {
             ranges.push(start.to_string());
         } else {
-            ranges.push(format!("{}-{}", start, end));
+            ranges.push(format!("{start}-{end}"));
         }
 
         i += 1;

crescendo/src/workers.rs

@@ -57,7 +57,7 @@ pub fn assign_workers(
                     if let Some(core_id) = core_ids.pop() {
                         result.push((core_id, worker_type));
                         *worker_counts.entry(worker_type).or_insert(0) += 1;
-                        worker_cores.entry(worker_type).or_insert_with(Vec::new).push(core_id);
+                        worker_cores.entry(worker_type).or_default().push(core_id);
                         remaining_cores -= 1;
                     }
                 }
@@ -74,7 +74,7 @@ pub fn assign_workers(
             if let Some(core_id) = core_ids.pop() {
                 result.push((core_id, *worker_type));
                 *worker_counts.entry(*worker_type).or_insert(0) += 1;
-                worker_cores.entry(*worker_type).or_insert_with(Vec::new).push(core_id);
+                worker_cores.entry(*worker_type).or_default().push(core_id);
                 remaining_cores -= 1;
             }
         }
@@ -87,26 +87,26 @@ pub fn assign_workers(
             if let Some(core_id) = core_ids.pop() {
                 result.push((core_id, worker_type));
                 *worker_counts.entry(worker_type).or_insert(0) += 1;
-                worker_cores.entry(worker_type).or_insert_with(Vec::new).push(core_id);
+                worker_cores.entry(worker_type).or_default().push(core_id);
             }
         }
     }
 
-    println!("[+] Spawning {} workers:", total_starting_cores);
+    println!("[+] Spawning {total_starting_cores} workers:");
     for (worker_type, count) in worker_counts.clone() {
         if log_core_ranges {
             if let Some(cores) = worker_cores.get(&worker_type) {
                 let mut core_ids: Vec<usize> = cores.iter().map(|c| c.id).collect();
                 core_ids.sort();
 
                 let core_str = match core_ids.as_slice() {
-                    [single] => format!("core {}", single),
+                    [single] => format!("core {single}"),
                     ids => format!("cores {}", format_ranges(ids)),
                 };
-                println!("- {:?}: {} ({})", worker_type, count, core_str);
+                println!("- {worker_type:?}: {count} ({core_str})");
             }
         } else {
-            println!("- {:?}: {}", worker_type, count);
+            println!("- {worker_type:?}: {count}");
         }
     }
 

crescendo/src/workers/network.rs

@@ -82,19 +82,19 @@ pub async fn network_worker(worker_id: usize) {
                                 NETWORK_STATS.inc_requests_by(txs.len() - error_count);
                             }
                             Err(e) => {
-                                eprintln!("[!] Failed to read response body: {:?}", e);
+                                eprintln!("[!] Failed to read response body: {e:?}");
                                 NETWORK_STATS.inc_errors_by(txs.len());
                                 tokio::time::sleep(Duration::from_millis(config.error_sleep_ms)).await;
                             }
                         }
                     } else {
-                        println!("[!] Request did not have OK status: {:?}", res);
+                        println!("[!] Request did not have OK status: {res:?}");
                         NETWORK_STATS.inc_errors_by(txs.len());
                         tokio::time::sleep(Duration::from_millis(100)).await;
                     }
                 }
                 Err(e) => {
-                    eprintln!("[!] Request failed: {:?}", e);
+                    eprintln!("[!] Request failed: {e:?}");
                     NETWORK_STATS.inc_errors_by(txs.len());
                     tokio::time::sleep(Duration::from_millis(100)).await;
                 }

crescendo/src/workers/tx_gen.rs

@@ -44,11 +44,12 @@ sol! {
 }
 
 pub fn tx_gen_worker(_worker_id: u32) {
+    let config = &config::get().tx_gen_worker;
+
     let mut rng = rand::rng();
+    let mut tx_batch = Vec::with_capacity(config.batch_size as usize);
 
     loop {
-        let config = &config::get().tx_gen_worker;
-
         let account_index = rng.random_range(0..config.num_accounts); // Acount we'll be sending from.
 
         // Get and increment nonce atomically.
@@ -83,7 +84,12 @@ pub fn tx_gen_worker(_worker_id: u32) {
             },
         );
 
-        TX_QUEUE.push_tx(tx);
+        tx_batch.push(tx);
+
+        // Once we've accumulated batch_size transactions, drain them all to the queue.
+        if tx_batch.len() >= config.batch_size as usize {
+            TX_QUEUE.push_txs(std::mem::take(&mut tx_batch));
+        }
     }
 }