Dynamic QBFT Timeout

sips/dynamic_qbft_timeout.md

@@ -0,0 +1,90 @@
+| Author         | Title                 | Category | Status   |
+| -------------- | --------------------- | -------- | -------- |
+| Gal Rogozinski |  QBFT timeout | Core     | approved |
+
+
+**Summary**  
+Changes to the constant timeouts we defined in [SIP#6](https://github.com/bloxapp/SIPs/blob/main/sips/constant_qbft_timeout.md) that should improve performance. 
+
+**Rational**  
+Currently for all duties, we have a `quickTimeout` of 2 seconds before sending a `RoundChange` message and a `slowTimeout` of 2 minutes starting from the 8th round.The timer starts when the QBFT instance starts. This approach has 2 issues:
+
+1. Duties that require a pre-consensus stage may start their instances at different times, causing some nodes to timeout sooner than others. This will result in a greater probability of a failed first round.
+2. Different duties have different timing assumptions, which may cause some duties to execute earlier than others.
+
+
+
+**Beacon Duty Timing Assumptions**  
+The Beacon chain has some timing assumptions regarding duty execution for maximizing rewards.
+
+| Duty           | Timing Assumption | Dependency     | Description                                                                                                         |
+| -------------- | ----------------- | -------------- | ------------------------------------------------------------------------------------------------------------------- |
+| Proposal       | < 4 Sec           | ---            | Attestations wait 4 seconds for a block                                                                             |
+| Attester       | < 4 Sec           | Proposal       | Attestations wait 4 seconds for a block then need to be propogated within 4 seconds for aggregators to pick them up |
+| Aggregator     | < 4 Sec           | Attester       | Aggregators start aggregating within 8 seconds from slot start and need to propogate within 4 seconds               |
+| Sync Committee | < 4 sec           | Proposal       | Sync Committee wait 4 seconds for a block                                                                           |
+| Contribution   | < 4 sec           | Sync Committee | Contributions wait 8 seconds from the slot start                                                                    |
+
+
+
+**Specification**
+
+From the slot start time after `baseDuration` delay wait 2 seconds before emitting a `RoundChange` message until the 6th round (inclusive). Afterwards, wait 2 minutes.
+
+```go
+var (
+	// quickTimeoutThreshold is the round after which the timeout duration increases to 2 minutes
+	quickTimeoutThreshold = Round(6)
+	// quickTimeout is the timeout in seconds for the first 6 rounds
+	quickTimeout int64 = 2 // 2 seconds
+	// slowTimeout is the timeout in seconds for rounds after the first 6
+	slowTimeout int64 = 120 // 2 minutes
+)
+
+// RoundTimeout returns the unix epoch time (seconds) in which we should send a RC message
+// Called for all beacon duties other than proposals
+func RoundTimeout(round Round, height Height, baseDuration int64, network types.BeaconNetwork) int64 {
+	// Calculate additional timeout in seconds based on round
+	var additionalTimeout int64
+	additionalTimeout = int64(min(round, quickTimeoutThreshold)) * quickTimeout
+	if round > quickTimeoutThreshold {
+		slowPortion := int64(round-quickTimeoutThreshold) * slowTimeout
+		additionalTimeout += slowPortion
+	}
+
+	// Combine base duration and additional timeout
+	timeoutDuration := baseDuration + additionalTimeout
+
+	// Get the unix epoch start time of the duty seconds
+	dutyStartTime := network.EstimatedTimeAtSlot(phase0.Slot(height))
+
+	// Calculate the time until the duty should start plus the timeout duration
+	return dutyStartTime + timeoutDuration
+}
+```
+
+*Proposals*
+
+No changes from [SIP#6](https://github.com/bloxapp/SIPs/blob/main/sips/constant_qbft_timeout.md). Doesn't rely on the slot/duty start time.
+
+*Attestations/Sync Committees*
+
+Once the slot starts, wait 4 seconds for a block to be produced then start the timer according to the new rules.
+
+```go
+// AttestationOrSyncCommitteeTimeout returns the unix epoch time (seconds) in which we should send a RC message
+func AttestationOrSyncCommitteeTimeout(round Round, height Height, network types.BeaconNetwork) int64 {
+	return RoundTimeout(round, height, 4, network)
+}
+```
+
+*Aggregator/Contribution*
+
+Once the slot starts, wait 8 seconds for a block to be produced then start the timer according to the new rules
+
+```go
+// AggregationOrContributionTimeout returns the unix epoch time (seconds) in which we should send a RC message
+func AggregationOrContributionTimeout(r Round, height Height, network types.BeaconNetwork) int64 {
+	return RoundTimeout(r, height, 8, network)
+}
+```