Estimate max block size

Cargo.toml

@@ -13,6 +13,7 @@ async-compatibility-layer = { version = "1.1", default-features = false, feature
 async-lock = "2.8"
 async-std = { version = "1.9.0", features = ["unstable", "attributes"] }
 async-trait = "0.1"
+bincode = "1.3"
 clap = { version = "4.5", features = ["derive", "env"] }
 committable = "0.2"
 derivative = "2.2"
@@ -37,4 +38,6 @@ hex = "0.4.3"
 hotshot-example-types = { git = "https://github.com/EspressoSystems/HotShot.git", tag = "0.5.70" }
 
 [lints.rust]
-unexpected_cfgs = { level = "warn", check-cfg = ['cfg(async_executor_impl, values("async-std", "tokio"))'] }
+unexpected_cfgs = { level = "warn", check-cfg = [
+    'cfg(async_executor_impl, values("async-std", "tokio"))',
+] }

src/builder_state.rs

@@ -32,7 +32,7 @@ use async_std::task::spawn_blocking;
 #[cfg(async_executor_impl = "tokio")]
 use tokio::task::spawn_blocking;
 
-use std::collections::{HashMap, HashSet};
+use std::collections::{HashMap, HashSet, VecDeque};
 use std::fmt::Debug;
 use std::sync::Arc;
 use std::time::Instant;
@@ -87,6 +87,8 @@ pub struct BuildBlockInfo<TYPES: NodeType> {
     pub metadata: <<TYPES as NodeType>::BlockPayload as BlockPayload<TYPES>>::Metadata,
     pub vid_trigger: OneShotSender<TriggerStatus>,
     pub vid_receiver: UnboundedReceiver<(VidCommitment, VidPrecomputeData)>,
+    // Could we have included more transactions, but chose not to?
+    pub truncated: bool,
 }
 
 /// Response Message to be put on the response channel
@@ -169,7 +171,7 @@ pub struct BuilderState<TYPES: NodeType> {
     pub tx_receiver: BroadcastReceiver<Arc<ReceivedTransaction<TYPES>>>,
 
     /// filtered queue of available transactions, taken from tx_receiver
-    pub tx_queue: Vec<Arc<ReceivedTransaction<TYPES>>>,
+    pub tx_queue: VecDeque<Arc<ReceivedTransaction<TYPES>>>,
 
     /// global state handle, defined in the service.rs
     pub global_state: Arc<RwLock<GlobalState<TYPES>>>,
@@ -490,17 +492,50 @@ impl<TYPES: NodeType> BuilderState<TYPES> {
 
             async_sleep(sleep_interval).await
         }
+
+        // Don't build an empty block
+        if self.tx_queue.is_empty() {
+            return None;
+        }
+
+        let max_block_size = self.global_state.read_arc().await.max_block_size;
+        let transactions_to_include = self.tx_queue.iter().scan(0, |total_size, tx| {
+            if *total_size >= max_block_size {
+                None
+            } else {
+                // This way we will include one transaction over our target block length.
+                // This is done on purpose, otherwise we'd have a possible failure state
+                // where a single transaction larger than target block state is stuck in
+                // queue and we just build empty blocks
+                *total_size += tx.len;
+                Some(tx.tx.clone())
+            }
+        });
+
         if let Ok((payload, metadata)) =
             <TYPES::BlockPayload as BlockPayload<TYPES>>::from_transactions(
-                self.tx_queue.iter().map(|tx| tx.tx.clone()),
+                transactions_to_include,
                 &self.validated_state,
                 &self.instance_state,
             )
             .await
         {
             let builder_hash = payload.builder_commitment(&metadata);
             // count the number of txns
-            let txn_count = self.tx_queue.len();
+            let actual_txn_count = payload.num_transactions(&metadata);
+
+            // Payload is empty despite us checking that tx_queue isn't empty earlier.
+            // This indicates that the block was truncated due to sequencer block length
+            // limits and we have a transaction too big to ever be included in the head of
+            // our queue. We need to drop it and mark as "included" so that if we receive
+            // it again we don't even bother with it.
+            if actual_txn_count == 0 {
+                if let Some(txn) = self.tx_queue.pop_front() {
+                    self.txns_in_queue.remove(&txn.commit);
+                    self.included_txns.insert(txn.commit);
+                };
+                return None;
+            }
 
             // insert the recently built block into the builder commitments
             self.builder_commitments
@@ -536,7 +571,7 @@ impl<TYPES: NodeType> BuilderState<TYPES> {
             tracing::info!(
                 "Builder view num {:?}, building block with {:?} txns, with builder hash {:?}",
                 self.built_from_proposed_block.view_number,
-                txn_count,
+                actual_txn_count,
                 builder_hash
             );
 
@@ -551,6 +586,7 @@ impl<TYPES: NodeType> BuilderState<TYPES> {
                 metadata,
                 vid_trigger: trigger_send,
                 vid_receiver: unbounded_receiver,
+                truncated: actual_txn_count < self.tx_queue.len(),
             })
         } else {
             tracing::warn!("build block, returning None");
@@ -744,7 +780,7 @@ impl<TYPES: NodeType> BuilderState<TYPES> {
         qc_receiver: BroadcastReceiver<MessageType<TYPES>>,
         req_receiver: BroadcastReceiver<MessageType<TYPES>>,
         tx_receiver: BroadcastReceiver<Arc<ReceivedTransaction<TYPES>>>,
-        tx_queue: Vec<Arc<ReceivedTransaction<TYPES>>>,
+        tx_queue: VecDeque<Arc<ReceivedTransaction<TYPES>>>,
         global_state: Arc<RwLock<GlobalState<TYPES>>>,
         num_nodes: NonZeroUsize,
         maximize_txn_capture_timeout: Duration,
@@ -841,7 +877,7 @@ impl<TYPES: NodeType> BuilderState<TYPES> {
                         continue;
                     }
                     self.txns_in_queue.insert(tx.commit);
-                    self.tx_queue.push(tx);
+                    self.tx_queue.push_back(tx);
                 }
                 Err(async_broadcast::TryRecvError::Empty)
                 | Err(async_broadcast::TryRecvError::Closed) => {

src/service.rs

@@ -60,6 +60,11 @@ use std::{fmt::Display, time::Instant};
 use tagged_base64::TaggedBase64;
 use tide_disco::{method::ReadState, Url};
 
+// Start assuming we're fine calculatig VID for 100 kilobyte blocks
+const INITIAL_MAX_BLOCK_SIZE: u64 = 100_000;
+// Never go lower than 10 kilobytes
+const MAX_BLOCK_SIZE_FLOOR: u64 = 10_000;
+
 // It holds all the necessary information for a block
 #[derive(Debug)]
 pub struct BlockInfo<Types: NodeType> {
@@ -68,6 +73,8 @@ pub struct BlockInfo<Types: NodeType> {
     pub vid_trigger: Arc<RwLock<Option<OneShotSender<TriggerStatus>>>>,
     pub vid_receiver: Arc<RwLock<WaitAndKeep<(VidCommitment, VidPrecomputeData)>>>,
     pub offered_fee: u64,
+    // Could we have included more transactions with this block, but chose not to?
+    pub truncated: bool,
 }
 
 // It holds the information for the proposed block
@@ -105,9 +112,11 @@ pub struct BuilderStatesInfo<Types: NodeType> {
 pub struct ReceivedTransaction<Types: NodeType> {
     // the transaction
     pub tx: Types::Transaction,
-    // its hash
+    // transaction's hash
     pub commit: Commitment<Types::Transaction>,
-    // its source
+    // transaction's esitmated length
+    pub len: u64,
+    // transaction's source
     pub source: TransactionSource,
     // received time
     pub time_in: Instant,
@@ -135,6 +144,9 @@ pub struct GlobalState<Types: NodeType> {
 
     // highest view running builder task
     pub highest_view_num_builder_id: BuilderStateId<Types>,
+
+    // estimated maximum block size we can build in time
+    pub max_block_size: u64,
 }
 
 impl<Types: NodeType> GlobalState<Types> {
@@ -160,6 +172,7 @@ impl<Types: NodeType> GlobalState<Types> {
             last_garbage_collected_view_num,
             builder_state_to_last_built_block: Default::default(),
             highest_view_num_builder_id: bootstrap_id,
+            max_block_size: INITIAL_MAX_BLOCK_SIZE,
         }
     }
 
@@ -203,6 +216,7 @@ impl<Types: NodeType> GlobalState<Types> {
                         build_block_info.vid_receiver,
                     ))),
                     offered_fee: build_block_info.offered_fee,
+                    truncated: build_block_info.truncated,
                 },
             );
         }
@@ -599,6 +613,15 @@ where
                     Err(_toe) => {
                         if Instant::now() >= timeout_after {
                             tracing::warn!("Couldn't get vid commitment in time for block {id}",);
+                            {
+                                // we can't keep up with this block size, reduce max block size by 10%
+                                let mut global_state = self.global_state.write_arc().await;
+                                global_state.max_block_size = std::cmp::min(
+                                    global_state.max_block_size
+                                        - global_state.max_block_size.div_ceil(10),
+                                    MAX_BLOCK_SIZE_FLOOR,
+                                );
+                            }
                             break Err(BuildError::Error {
                                 message: "Couldn't get vid commitment in time".to_string(),
                             });
@@ -619,6 +642,18 @@ where
             };
 
             tracing::info!("Got vid commitment for block {id}",);
+
+            // This block was truncated, but we got VID in time.
+            // Maybe we can handle bigger blocks?
+            if block_info.truncated {
+                // Increase max block size by 10%
+                let mut global_state = self.global_state.write_arc().await;
+                global_state.max_block_size = std::cmp::min(
+                    global_state.max_block_size + global_state.max_block_size.div_ceil(10),
+                    MAX_BLOCK_SIZE_FLOOR,
+                );
+            }
+
             if response_received.is_ok() {
                 let (vid_commitment, vid_precompute_data) =
                     response_received.map_err(|err| BuildError::Error {
@@ -1062,12 +1097,14 @@ pub(crate) async fn handle_received_txns<Types: NodeType>(
     let time_in = Instant::now();
     for tx in txns.into_iter() {
         let commit = tx.commit();
+        let len = bincode::serialized_size(&tx).unwrap_or_default();
         let res = tx_sender
             .try_broadcast(Arc::new(ReceivedTransaction {
                 tx,
                 source: source.clone(),
                 commit,
                 time_in,
+                len,
             }))
             .inspect(|val| {
                 if let Some(evicted_txn) = val {

src/testing/basic_test.rs

@@ -18,6 +18,7 @@ pub use async_broadcast::{
 #[cfg(test)]
 mod tests {
     use super::*;
+    use std::collections::VecDeque;
     use std::{hash::Hash, marker::PhantomData, num::NonZeroUsize};
 
     use async_compatibility_layer::channel::unbounded;
@@ -100,7 +101,7 @@ mod tests {
         let (tx_sender, tx_receiver) = broadcast::<Arc<ReceivedTransaction<TestTypes>>>(
             num_test_messages * multiplication_factor,
         );
-        let tx_queue = Vec::new();
+        let tx_queue = VecDeque::new();
         // generate the keys for the buidler
         let seed = [201_u8; 32];
         let (_builder_pub_key, _builder_private_key) =