All tasks wait before starting

linera-client/src/benchmark.rs

@@ -1,7 +1,7 @@
 // Copyright (c) Zefchain Labs, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-use std::{collections::HashMap, iter};
+use std::{collections::HashMap, iter, sync::Arc};
 
 use linera_base::{
     crypto::{AccountPublicKey, AccountSecretKey},
@@ -25,7 +25,11 @@ use linera_sdk::abis::fungible;
 use linera_storage::Storage;
 use num_format::{Locale, ToFormattedString};
 use prometheus_parse::{HistogramCount, Scrape, Value};
-use tokio::{runtime::Handle, sync::mpsc, task, time};
+use tokio::{
+    runtime::Handle,
+    sync::{mpsc, Barrier},
+    task, time,
+};
 use tokio_util::sync::CancellationToken;
 use tracing::{debug, error, info, warn, Instrument as _};
 
@@ -173,9 +177,9 @@ where
             let mut tasks_running = 0;
             while let Some(()) = bps_tasks_logger_receiver.recv().await {
                 tasks_running += 1;
-                info!("{}/{} tasks running", tasks_running, num_chains);
+                info!("{}/{} tasks ready to start", tasks_running, num_chains);
                 if tasks_running == num_chains {
-                    info!("All tasks are running");
+                    info!("All tasks are ready to start");
                     break;
                 }
             }
@@ -184,6 +188,7 @@ where
         let mut bps_remainder = bps.unwrap_or_default() % num_chains;
         let bps_share = bps.map(|bps| bps / num_chains);
 
+        let barrier = Arc::new(Barrier::new(num_chains));
         let mut join_set = task::JoinSet::<Result<(), BenchmarkError>>::new();
         for (chain_id, operations, key_pair) in blocks_infos {
             let bps_share = if bps_remainder > 0 {
@@ -200,6 +205,7 @@ where
             let local_node = local_node.clone();
             let chain_client = chain_clients[&chain_id].clone();
             let bps_tasks_logger_sender = bps_tasks_logger_sender.clone();
+            let inner_barrier = barrier.clone();
             chain_client.process_inbox().await?;
             join_set.spawn_blocking(move || {
                 handle.block_on(
@@ -215,6 +221,7 @@ where
                             committee,
                             local_node,
                             bps_tasks_logger_sender,
+                            inner_barrier,
                         ))
                         .await?;
 
@@ -503,13 +510,15 @@ where
         committee: Committee,
         local_node: LocalNodeClient<S>,
         bps_tasks_logger_sender: mpsc::Sender<()>,
+        barrier: Arc<Barrier>,
     ) -> Result<(), BenchmarkError> {
         let chain_id = chain_client.chain_id();
+        bps_tasks_logger_sender.send(()).await?;
+        barrier.wait().await;
         info!(
             "Starting benchmark at target BPS of {:?}, for chain {:?}",
             bps, chain_id
         );
-        bps_tasks_logger_sender.send(()).await?;
         let cross_chain_message_delivery = chain_client.options().cross_chain_message_delivery;
         let mut num_sent_proposals = 0;
         let authenticated_signer = Some(AccountOwner::from(key_pair.public()));