prysm-pulse/beacon-chain/casper/incentives.go

109 lines
4.1 KiB
Go
Raw Normal View History

package casper
import (
"github.com/prysmaticlabs/prysm/beacon-chain/params"
pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
"github.com/prysmaticlabs/prysm/shared/mathutil"
"github.com/sirupsen/logrus"
)
var log = logrus.WithField("prefix", "casper")
// CalculateRewards adjusts validators balances by applying rewards or penalties
// based on FFG incentive structure.
// FFG Rewards scheme rewards validator who have voted on blocks, and penalises those validators
// who are offline. The penalties are more severe the longer they are offline.
func CalculateRewards(
slot uint64,
voterIndices []uint32,
validators []*pb.ValidatorRecord,
totalParticipatedDeposit uint64,
timeSinceFinality uint64) []*pb.ValidatorRecord {
totalDeposit := TotalActiveValidatorDeposit(validators)
activeValidators := ActiveValidatorIndices(validators)
rewardQuotient := RewardQuotient(validators)
penaltyQuotient := quadraticPenaltyQuotient()
log.Debugf("Applying rewards and penalties for the validators for slot %d", slot)
if timeSinceFinality <= 3*params.GetConfig().CycleLength {
for _, validatorIndex := range activeValidators {
var voted bool
for _, voterIndex := range voterIndices {
if voterIndex == validatorIndex {
voted = true
balance := validators[validatorIndex].GetBalance()
newbalance := int64(balance) + int64(balance/rewardQuotient)*(2*int64(totalParticipatedDeposit)-int64(totalDeposit))/int64(totalDeposit)
validators[validatorIndex].Balance = uint64(newbalance)
break
}
}
if !voted {
newBalance := validators[validatorIndex].GetBalance()
newBalance -= newBalance / rewardQuotient
validators[validatorIndex].Balance = newBalance
}
}
} else {
for _, validatorIndex := range activeValidators {
var voted bool
for _, voterIndex := range voterIndices {
if voterIndex == validatorIndex {
voted = true
break
}
}
if !voted {
newBalance := validators[validatorIndex].GetBalance()
newBalance -= newBalance/rewardQuotient + newBalance*timeSinceFinality/penaltyQuotient
validators[validatorIndex].Balance = newBalance
}
}
}
return validators
}
// RewardQuotient returns the reward quotient for validators which will be used to
// reward validators for voting on blocks, or penalise them for being offline.
func RewardQuotient(validators []*pb.ValidatorRecord) uint64 {
totalDepositETH := TotalActiveValidatorDepositInEth(validators)
return params.GetConfig().BaseRewardQuotient * mathutil.IntegerSquareRoot(totalDepositETH)
}
// quadraticPenaltyQuotient is the quotient that will be used to apply penalties to offline
// validators.
func quadraticPenaltyQuotient() uint64 {
dropTimeFactor := params.GetConfig().SqrtExpDropTime
return dropTimeFactor * dropTimeFactor
}
// QuadraticPenalty returns the penalty that will be applied to an offline validator
// based on the number of slots that they are offline.
func QuadraticPenalty(numberOfSlots uint64) uint64 {
slotFactor := (numberOfSlots * numberOfSlots) / 2
penaltyQuotient := quadraticPenaltyQuotient()
return slotFactor / penaltyQuotient
}
// RewardValidatorCrosslink applies rewards to validators part of a shard committee for voting on a shard.
// TODO(#538): Change this to big.Int as tests using 64 bit integers fail due to integer overflow.
func RewardValidatorCrosslink(totalDeposit uint64, participatedDeposits uint64, rewardQuotient uint64, validator *pb.ValidatorRecord) {
currentBalance := int64(validator.Balance)
currentBalance += int64(currentBalance) / int64(rewardQuotient) * (2*int64(participatedDeposits) - int64(totalDeposit)) / int64(totalDeposit)
validator.Balance = uint64(currentBalance)
}
// PenaliseValidatorCrosslink applies penalties to validators part of a shard committee for not voting on a shard.
func PenaliseValidatorCrosslink(timeSinceLastConfirmation uint64, rewardQuotient uint64, validator *pb.ValidatorRecord) {
newBalance := validator.Balance
quadraticQuotient := quadraticPenaltyQuotient()
newBalance -= newBalance/rewardQuotient + newBalance*timeSinceLastConfirmation/quadraticQuotient
validator.Balance = newBalance
}