CongestionTracker:

- Witnesses congestion failures from checkpointed effects
- Returns a suggested gas price given a set of input objects

crates/sui-core/src/authority.rs

@@ -2,6 +2,7 @@
 // Copyright (c) Mysten Labs, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
+use crate::congestion_tracker::CongestionTracker;
 use crate::consensus_adapter::ConsensusOverloadChecker;
 use crate::execution_cache::ExecutionCacheTraitPointers;
 use crate::execution_cache::TransactionCacheRead;
@@ -831,6 +832,8 @@ pub struct AuthorityState {
 
     /// The chain identifier is derived from the digest of the genesis checkpoint.
     chain_identifier: ChainIdentifier,
+
+    pub(crate) congestion_tracker: Arc<CongestionTracker>,
 }
 
 /// The authority state encapsulates all state, drives execution, and ensures safety.
@@ -2938,6 +2941,7 @@ impl AuthorityState {
             overload_info: AuthorityOverloadInfo::default(),
             validator_tx_finalizer,
             chain_identifier,
+            congestion_tracker: Arc::new(CongestionTracker::new()),
         });
 
         // Start a task to execute ready certificates.

crates/sui-core/src/checkpoints/checkpoint_executor/mod.rs

@@ -1391,6 +1391,14 @@ async fn finalize_checkpoint(
     debug!("finalizing checkpoint");
     epoch_store.insert_finalized_transactions(tx_digests, checkpoint.sequence_number)?;
 
+    if state.is_fullnode(epoch_store) {
+        state.congestion_tracker.process_checkpoint_effects(
+            transaction_cache_reader,
+            &checkpoint,
+            &effects,
+        );
+    }
+
     // TODO remove once we no longer need to support this table for read RPC
     state
         .get_checkpoint_cache()

crates/sui-core/src/congestion_tracker.rs

@@ -0,0 +1,334 @@
+// Copyright (c) Mysten Labs, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+use moka::ops::compute::Op;
+use moka::sync::Cache;
+use std::collections::hash_map::Entry;
+use std::collections::HashMap;
+use sui_types::base_types::ObjectID;
+use sui_types::effects::{InputSharedObject, TransactionEffects, TransactionEffectsAPI};
+use sui_types::execution_status::CongestedObjects;
+use sui_types::messages_checkpoint::{CheckpointTimestamp, VerifiedCheckpoint};
+use sui_types::transaction::{TransactionData, TransactionDataAPI};
+
+use crate::execution_cache::TransactionCacheRead;
+
+#[derive(Clone, Copy, Debug)]
+pub struct CongestionInfo {
+    pub last_cancellation_time: CheckpointTimestamp,
+
+    pub highest_cancelled_gas_price: u64,
+
+    pub last_success_time: Option<CheckpointTimestamp>,
+    pub lowest_executed_gas_price: Option<u64>,
+}
+
+impl CongestionInfo {
+    /// Update the congestion info with the latest congestion info from a new checkpoint
+    fn update_for_new_checkpoint(&mut self, new: &CongestionInfo) {
+        // If there are more recent cancellations, we need to know the latest highest
+        // cancelled price
+        if new.last_cancellation_time > self.last_cancellation_time {
+            self.last_cancellation_time = new.last_cancellation_time;
+            self.highest_cancelled_gas_price = new.highest_cancelled_gas_price;
+        }
+        // If there are more recent successful transactions, we need to know the latest lowest
+        // executed price
+        if new.last_success_time > self.last_success_time {
+            self.last_success_time = new.last_success_time;
+            self.lowest_executed_gas_price = new.lowest_executed_gas_price;
+        }
+    }
+
+    fn update_for_cancellation(&mut self, now: CheckpointTimestamp, gas_price: u64) {
+        self.last_cancellation_time = now;
+        self.highest_cancelled_gas_price =
+            std::cmp::max(self.highest_cancelled_gas_price, gas_price);
+    }
+
+    fn update_for_success(&mut self, now: CheckpointTimestamp, gas_price: u64) {
+        self.last_success_time = Some(now);
+        self.lowest_executed_gas_price = Some(match self.lowest_executed_gas_price {
+            Some(current_min) => std::cmp::min(current_min, gas_price),
+            None => gas_price,
+        });
+    }
+}
+
+pub struct CongestionTracker {
+    pub congestion_clearing_prices: Cache<ObjectID, CongestionInfo>,
+}
+
+impl Default for CongestionTracker {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl CongestionTracker {
+    pub fn new() -> Self {
+        Self {
+            congestion_clearing_prices: Cache::new(10_000),
+        }
+    }
+
+    pub fn process_checkpoint_effects(
+        &self,
+        transaction_cache_reader: &dyn TransactionCacheRead,
+        checkpoint: &VerifiedCheckpoint,
+        effects: &[TransactionEffects],
+    ) {
+        let mut congestion_events = Vec::with_capacity(effects.len());
+        let mut cleared_events = Vec::with_capacity(effects.len());
+
+        for effect in effects {
+            let gas_price = transaction_cache_reader
+                .get_transaction_block(effect.transaction_digest())
+                .unwrap()
+                .transaction_data()
+                .gas_price();
+            if let Some(CongestedObjects(congested_objects)) =
+                effect.status().get_congested_objects()
+            {
+                congestion_events.push((gas_price, congested_objects.clone()));
+            } else {
+                cleared_events.push((
+                    gas_price,
+                    effect
+                        .input_shared_objects()
+                        .into_iter()
+                        .filter_map(|object| match object {
+                            InputSharedObject::Mutate((id, _, _)) => Some(id),
+                            InputSharedObject::Cancelled(_, _)
+                            | InputSharedObject::ReadOnly(_)
+                            | InputSharedObject::ReadDeleted(_, _)
+                            | InputSharedObject::MutateDeleted(_, _) => None,
+                        })
+                        .collect::<Vec<_>>(),
+                ));
+            }
+        }
+
+        self.process_per_checkpoint_events(
+            checkpoint.timestamp_ms,
+            &congestion_events,
+            &cleared_events,
+        );
+    }
+
+    /// For all the mutable shared inputs, get the highest minimum clearing price (if any exists)
+    /// and the lowest maximum cancelled price.
+    pub fn get_suggested_gas_prices(&self, transaction: &TransactionData) -> Option<u64> {
+        self.get_suggested_gas_price_for_objects(
+            transaction
+                .shared_input_objects()
+                .into_iter()
+                .filter(|id| id.mutable)
+                .map(|id| id.id),
+        )
+    }
+}
+
+impl CongestionTracker {
+    fn process_per_checkpoint_events(
+        &self,
+        now: CheckpointTimestamp,
+        congestion_events: &[(u64, Vec<ObjectID>)],
+        cleared_events: &[(u64, Vec<ObjectID>)],
+    ) {
+        let congestion_info_map =
+            self.compute_per_checkpoint_congestion_info(now, congestion_events, cleared_events);
+        self.process_checkpoint_congestion(congestion_info_map);
+    }
+
+    fn get_suggested_gas_price_for_objects(
+        &self,
+        objects: impl Iterator<Item = ObjectID>,
+    ) -> Option<u64> {
+        let mut clearing_price = None;
+        for object_id in objects {
+            if let Some(info) = self.get_congestion_info(object_id) {
+                let clearing_price_for_object = match info
+                    .last_success_time
+                    .cmp(&Some(info.last_cancellation_time))
+                {
+                    std::cmp::Ordering::Greater => {
+                        // there were no cancellations in the most recent checkpoint,
+                        // so the object is probably not congested any more
+                        None
+                    }
+                    std::cmp::Ordering::Less => {
+                        // there were no successes in the most recent checkpoint. This should be a rare case,
+                        // but we know we will have to bid at least as much as the highest cancelled price.
+                        Some(info.highest_cancelled_gas_price)
+                    }
+                    std::cmp::Ordering::Equal => {
+                        // there were both successes and cancellations.
+                        info.lowest_executed_gas_price
+                    }
+                };
+                clearing_price = std::cmp::max(clearing_price, clearing_price_for_object);
+            }
+        }
+        clearing_price
+    }
+
+    fn compute_per_checkpoint_congestion_info(
+        &self,
+        now: CheckpointTimestamp,
+        congestion_events: &[(u64, Vec<ObjectID>)],
+        cleared_events: &[(u64, Vec<ObjectID>)],
+    ) -> HashMap<ObjectID, CongestionInfo> {
+        let mut congestion_info_map: HashMap<ObjectID, CongestionInfo> = HashMap::new();
+
+        for (gas_price, objects) in congestion_events {
+            for object in objects {
+                match congestion_info_map.entry(*object) {
+                    Entry::Occupied(entry) => {
+                        entry.into_mut().update_for_cancellation(now, *gas_price);
+                    }
+                    Entry::Vacant(entry) => {
+                        let info = CongestionInfo {
+                            last_cancellation_time: now,
+                            highest_cancelled_gas_price: *gas_price,
+                            last_success_time: None,
+                            lowest_executed_gas_price: None,
+                        };
+
+                        entry.insert(info);
+                    }
+                }
+            }
+        }
+
+        for (gas_price, objects) in cleared_events {
+            for object in objects {
+                // We only record clearing prices if the object has observed cancellations recently
+                match congestion_info_map.entry(*object) {
+                    Entry::Occupied(entry) => {
+                        entry.into_mut().update_for_success(now, *gas_price);
+                    }
+                    Entry::Vacant(entry) => {
+                        if let Some(prev) = self.get_congestion_info(*object) {
+                            let info = CongestionInfo {
+                                last_cancellation_time: prev.last_cancellation_time,
+                                highest_cancelled_gas_price: prev.highest_cancelled_gas_price,
+                                last_success_time: Some(now),
+                                lowest_executed_gas_price: Some(*gas_price),
+                            };
+                            entry.insert(info);
+                        }
+                    }
+                }
+            }
+        }
+
+        congestion_info_map
+    }
+
+    fn process_checkpoint_congestion(
+        &self,
+        congestion_info_map: HashMap<ObjectID, CongestionInfo>,
+    ) {
+        for (object_id, info) in congestion_info_map {
+            self.congestion_clearing_prices
+                .entry(object_id)
+                .and_compute_with(|maybe_entry| {
+                    if let Some(e) = maybe_entry {
+                        let mut e = e.into_value();
+                        e.update_for_new_checkpoint(&info);
+                        Op::Put(e)
+                    } else {
+                        Op::Put(info)
+                    }
+                });
+        }
+    }
+
+    fn get_congestion_info(&self, object_id: ObjectID) -> Option<CongestionInfo> {
+        self.congestion_clearing_prices.get(&object_id)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_process_events_new_congestion() {
+        let tracker = CongestionTracker::new();
+        let obj1 = ObjectID::random();
+        let obj2 = ObjectID::random();
+        let now = 1000;
+
+        tracker.process_per_checkpoint_events(now, &[(100, vec![obj1]), (200, vec![obj2])], &[]);
+
+        assert_eq!(
+            tracker.get_suggested_gas_price_for_objects(vec![obj1].into_iter()),
+            Some(100)
+        );
+        assert_eq!(
+            tracker.get_suggested_gas_price_for_objects(vec![obj2].into_iter()),
+            Some(200)
+        );
+    }
+
+    #[test]
+    fn test_process_events_congestion_then_success() {
+        let tracker = CongestionTracker::new();
+        let obj = ObjectID::random();
+
+        // Cancellations only, no successes. Highest cancelled price is used.
+        tracker.process_per_checkpoint_events(1000, &[(100, vec![obj]), (75, vec![obj])], &[]);
+        assert_eq!(
+            tracker.get_suggested_gas_price_for_objects(vec![obj].into_iter()),
+            Some(100)
+        );
+
+        // No cancellations in last checkpoint, so no congestion
+        tracker.process_per_checkpoint_events(2000, &[], &[(150, vec![obj])]);
+        assert_eq!(
+            tracker.get_suggested_gas_price_for_objects(vec![obj].into_iter()),
+            None,
+        );
+
+        // next checkpoint has cancellations and successes, so the lowest success price is used.
+        tracker.process_per_checkpoint_events(
+            3000,
+            &[(100, vec![obj])],
+            &[(175, vec![obj]), (125, vec![obj])],
+        );
+        assert_eq!(
+            tracker.get_suggested_gas_price_for_objects(vec![obj].into_iter()),
+            Some(125)
+        );
+    }
+
+    #[test]
+    fn test_get_suggested_gas_price_multiple_objects() {
+        let tracker = CongestionTracker::new();
+        let obj1 = ObjectID::random();
+        let obj2 = ObjectID::random();
+
+        // Process different congestion events
+        tracker.process_per_checkpoint_events(1000, &[(100, vec![obj1]), (200, vec![obj2])], &[]);
+
+        // Should suggest highest congestion price
+        assert_eq!(
+            tracker.get_suggested_gas_price_for_objects(vec![obj1, obj2].into_iter()),
+            Some(200)
+        );
+
+        // Process different congestion events
+        tracker.process_per_checkpoint_events(
+            2000,
+            &[(100, vec![obj1]), (200, vec![obj2])],
+            &[(100, vec![obj1]), (150, vec![obj2])],
+        );
+        // Should suggest the highest lowest success price
+        assert_eq!(
+            tracker.get_suggested_gas_price_for_objects(vec![obj1, obj2].into_iter()),
+            Some(150)
+        );
+    }
+}

crates/sui-core/src/lib.rs

@@ -9,6 +9,7 @@ pub mod authority_aggregator;
 pub mod authority_client;
 pub mod authority_server;
 pub mod checkpoints;
+pub mod congestion_tracker;
 pub mod consensus_adapter;
 pub mod consensus_handler;
 pub mod consensus_manager;