types: sort validators by voting power

thus enabling faster commit verification assuming non uniform distribution of power. Closes #2478 spec: https://github.com/tendermint/spec/pull/91
2026-01-10 15:07:24 +00:00 · 2020-05-06 11:37:36 +04:00
parent f6435f2c73
commit 25890a6635
7 changed files with 134 additions and 100 deletions
--- a/CHANGELOG_PENDING.md
+++ b/CHANGELOG_PENDING.md
@@ -11,6 +11,7 @@ Friendly reminder, we have a [bug bounty program](https://hackerone.com/tendermi
 - CLI/RPC/Config

  - [evidence] \#4725 Remove `Pubkey` from DuplicateVoteEvidence
+  - [rpc] [\#4792](https://github.com/tendermint/tendermint/pull/4792) `/validators` are now sorted by voting power (@melekes)

 - Apps

@@ -25,6 +26,8 @@ Friendly reminder, we have a [bug bounty program](https://hackerone.com/tendermi

 - Blockchain Protocol

+  - [types] [\#4792](https://github.com/tendermint/tendermint/pull/4792) Sort validators by voting power to enable faster commit verification (@melekes)
+
 ### FEATURES:

 - [statesync] Add state sync support, where a new node can be rapidly bootstrapped by fetching state snapshots from peers instead of replaying blocks. See the `[statesync]` config section.
--- a/lite2/helpers_test.go
+++ b/lite2/helpers_test.go
@@ -78,7 +78,7 @@ func (pkz privKeys) signHeader(header *types.Header, first, last int) *types.Com
 	}

 	// We need this list to keep the ordering.
-	vset := pkz.ToValidators(1, 0)
+	vset := pkz.ToValidators(1, 1)

 	blockID := types.BlockID{
 		Hash:        header.Hash(),
--- a/rpc/swagger/swagger.yaml
+++ b/rpc/swagger/swagger.yaml
@@ -669,7 +669,7 @@ paths:
      tags:
        - Info
      description: |
-        Get Validators.
+        Get Validators. Validators are sorted by voting power.
      responses:
        200:
          description: Commit results.
--- a/state/validation.go
+++ b/state/validation.go
@@ -148,9 +148,14 @@ func validateBlock(evidencePool EvidencePool, stateDB dbm.DB, state State, block
 	// NOTE: We can't actually verify it's the right proposer because we dont
 	// know what round the block was first proposed. So just check that it's
 	// a legit address and a known validator.
-	if len(block.ProposerAddress) != crypto.AddressSize ||
-		!state.Validators.HasAddress(block.ProposerAddress) {
-		return fmt.Errorf("block.Header.ProposerAddress, %X, is not a validator",
+	if len(block.ProposerAddress) != crypto.AddressSize {
+		return fmt.Errorf("expected ProposerAddress size %d, got %d",
+			crypto.AddressSize,
+			len(block.ProposerAddress),
+		)
+	}
+	if !state.Validators.HasAddress(block.ProposerAddress) {
+		return fmt.Errorf("block.Header.ProposerAddress %X is not a validator",
 			block.ProposerAddress,
 		)
 	}
--- a/types/priv_validator.go
+++ b/types/priv_validator.go
@@ -18,9 +18,6 @@ type PrivValidator interface {
 	SignProposal(chainID string, proposal *Proposal) error
 }

-//----------------------------------------
-// Misc.
-
 type PrivValidatorsByAddress []PrivValidator

 func (pvs PrivValidatorsByAddress) Len() int {
--- a/types/validator_set.go
+++ b/types/validator_set.go
@@ -24,19 +24,23 @@ const (
 	// and leaves room for defensive purposes.
 	MaxTotalVotingPower = int64(math.MaxInt64) / 8

-	// PriorityWindowSizeFactor - is a constant that when multiplied with the total voting power gives
-	// the maximum allowed distance between validator priorities.
+	// PriorityWindowSizeFactor - is a constant that when multiplied with the
+	// total voting power gives the maximum allowed distance between validator
+	// priorities.
 	PriorityWindowSizeFactor = 2
 )

 // ValidatorSet represent a set of *Validator at a given height.
+//
 // The validators can be fetched by address or index.
-// The index is in order of .Address, so the indices are fixed
-// for all rounds of a given blockchain height - ie. the validators
-// are sorted by their address.
-// On the other hand, the .ProposerPriority of each validator and
-// the designated .GetProposer() of a set changes every round,
-// upon calling .IncrementProposerPriority().
+// The index is in order of .VotingPower, so the indices are fixed for all
+// rounds of a given blockchain height - ie. the validators are sorted by their
+// voting power (descending). Secondary index - .Address (ascending).
+//
+// On the other hand, the .ProposerPriority of each validator and the
+// designated .GetProposer() of a set changes every round, upon calling
+// .IncrementProposerPriority().
+//
 // NOTE: Not goroutine-safe.
 // NOTE: All get/set to validators should copy the value for safety.
 type ValidatorSet struct {
@@ -48,18 +52,21 @@ type ValidatorSet struct {
 	totalVotingPower int64
 }

-// NewValidatorSet initializes a ValidatorSet by copying over the
-// values from `valz`, a list of Validators. If valz is nil or empty,
-// the new ValidatorSet will have an empty list of Validators.
-// The addresses of validators in `valz` must be unique otherwise the
-// function panics.
-// Note the validator set size has an implied limit equal to that of the MaxVotesCount -
-// commits by a validator set larger than this will fail validation.
+// NewValidatorSet initializes a ValidatorSet by copying over the values from
+// `valz`, a list of Validators. If valz is nil or empty, the new ValidatorSet
+// will have an empty list of Validators.
+//
+// The addresses of validators in `valz` must be unique otherwise the function
+// panics.
+//
+// Note the validator set size has an implied limit equal to that of the
+// MaxVotesCount - commits by a validator set larger than this will fail
+// validation.
 func NewValidatorSet(valz []*Validator) *ValidatorSet {
 	vals := &ValidatorSet{}
 	err := vals.updateWithChangeSet(valz, false)
 	if err != nil {
-		panic(fmt.Sprintf("cannot create validator set: %s", err))
+		panic(fmt.Sprintf("Cannot create validator set: %v", err))
 	}
 	if len(valz) > 0 {
 		vals.IncrementProposerPriority(1)
@@ -80,8 +87,8 @@ func (vals *ValidatorSet) CopyIncrementProposerPriority(times int) *ValidatorSet
 	return copy
 }

-// IncrementProposerPriority increments ProposerPriority of each validator and updates the
-// proposer. Panics if validator set is empty.
+// IncrementProposerPriority increments ProposerPriority of each validator and
+// updates the proposer. Panics if validator set is empty.
 // `times` must be positive.
 func (vals *ValidatorSet) IncrementProposerPriority(times int) {
 	if vals.IsNilOrEmpty() {
@@ -107,8 +114,9 @@ func (vals *ValidatorSet) IncrementProposerPriority(times int) {
 	vals.Proposer = proposer
 }

-// RescalePriorities rescales the priorities such that the distance between the maximum and minimum
-// is smaller than `diffMax`.
+// RescalePriorities rescales the priorities such that the distance between the
+// maximum and minimum is smaller than `diffMax`. Panics if validator set is
+// empty.
 func (vals *ValidatorSet) RescalePriorities(diffMax int64) {
 	if vals.IsNilOrEmpty() {
 		panic("empty validator set")
@@ -226,25 +234,27 @@ func (vals *ValidatorSet) Copy() *ValidatorSet {
 // HasAddress returns true if address given is in the validator set, false -
 // otherwise.
 func (vals *ValidatorSet) HasAddress(address []byte) bool {
-	idx := sort.Search(len(vals.Validators), func(i int) bool {
-		return bytes.Compare(address, vals.Validators[i].Address) <= 0
-	})
-	return idx < len(vals.Validators) && bytes.Equal(vals.Validators[idx].Address, address)
+	for _, val := range vals.Validators {
+		if bytes.Equal(val.Address, address) {
+			return true
+		}
+	}
+	return false
 }

 // GetByAddress returns an index of the validator with address and validator
-// itself if found. Otherwise, -1 and nil are returned.
+// itself (copy) if found. Otherwise, -1 and nil are returned.
 func (vals *ValidatorSet) GetByAddress(address []byte) (index int, val *Validator) {
-	idx := sort.Search(len(vals.Validators), func(i int) bool {
-		return bytes.Compare(address, vals.Validators[i].Address) <= 0
-	})
-	if idx < len(vals.Validators) && bytes.Equal(vals.Validators[idx].Address, address) {
-		return idx, vals.Validators[idx].Copy()
+	for idx, val := range vals.Validators {
+		if bytes.Equal(val.Address, address) {
+			return idx, val.Copy()
+		}
 	}
 	return -1, nil
 }

-// GetByIndex returns the validator's address and validator itself by index.
+// GetByIndex returns the validator's address and validator itself (copy) by
+// index.
 // It returns nil values if index is less than 0 or greater or equal to
 // len(ValidatorSet.Validators).
 func (vals *ValidatorSet) GetByIndex(index int) (address []byte, val *Validator) {
@@ -263,7 +273,6 @@ func (vals *ValidatorSet) Size() int {
 // Forces recalculation of the set's total voting power.
 // Panics if total voting power is bigger than MaxTotalVotingPower.
 func (vals *ValidatorSet) updateTotalVotingPower() {
-
 	sum := int64(0)
 	for _, val := range vals.Validators {
 		// mind overflow
@@ -445,7 +454,6 @@ func numNewValidators(updates []*Validator, vals *ValidatorSet) int {
 //
 // No changes are made to the validator set 'vals'.
 func computeNewPriorities(updates []*Validator, vals *ValidatorSet, updatedTotalVotingPower int64) {
-
 	for _, valUpdate := range updates {
 		address := valUpdate.Address
 		_, val := vals.GetByAddress(address)
@@ -471,8 +479,9 @@ func computeNewPriorities(updates []*Validator, vals *ValidatorSet, updatedTotal
 // Expects updates to be a list of updates sorted by address with no duplicates or errors,
 // must have been validated with verifyUpdates() and priorities computed with computeNewPriorities().
 func (vals *ValidatorSet) applyUpdates(updates []*Validator) {
-
 	existing := vals.Validators
+	sort.Sort(ValidatorsByAddress(existing))
+
 	merged := make([]*Validator, len(existing)+len(updates))
 	i := 0

@@ -509,7 +518,6 @@ func (vals *ValidatorSet) applyUpdates(updates []*Validator) {
 // Checks that the validators to be removed are part of the validator set.
 // No changes are made to the validator set 'vals'.
 func verifyRemovals(deletes []*Validator, vals *ValidatorSet) (votingPower int64, err error) {
-
 	removedVotingPower := int64(0)
 	for _, valUpdate := range deletes {
 		address := valUpdate.Address
@@ -527,8 +535,8 @@ func verifyRemovals(deletes []*Validator, vals *ValidatorSet) (votingPower int64

 // Removes the validators specified in 'deletes' from validator set 'vals'.
 // Should not fail as verification has been done before.
+// Expects vals to be sorted by address (done by applyUpdates).
 func (vals *ValidatorSet) applyRemovals(deletes []*Validator) {
-
 	existing := vals.Validators

 	merged := make([]*Validator, len(existing)-len(deletes))
@@ -559,7 +567,6 @@ func (vals *ValidatorSet) applyRemovals(deletes []*Validator) {
 // are not allowed and will trigger an error if present in 'changes'.
 // The 'allowDeletes' flag is set to false by NewValidatorSet() and to true by UpdateWithChangeSet().
 func (vals *ValidatorSet) updateWithChangeSet(changes []*Validator, allowDeletes bool) error {
-
 	if len(changes) == 0 {
 		return nil
 	}
@@ -606,6 +613,8 @@ func (vals *ValidatorSet) updateWithChangeSet(changes []*Validator, allowDeletes
 	vals.RescalePriorities(PriorityWindowSizeFactor * vals.TotalVotingPower())
 	vals.shiftByAvgProposerPriority()

+	sort.Sort(ValidatorsByVotingPower(vals.Validators))
+
 	return nil
 }

@@ -883,42 +892,59 @@ func (vals *ValidatorSet) StringIndented(indent string) string {
 }

 //-------------------------------------
-// Implements sort for sorting validators by address.

-// ValidatorsByAddress implements the sort of validators by address.
+// ValidatorsByVotingPower implements sort.Interface for []*Validator based on
+// the VotingPower and Address fields.
+type ValidatorsByVotingPower []*Validator
+
+func (valz ValidatorsByVotingPower) Len() int { return len(valz) }
+
+func (valz ValidatorsByVotingPower) Less(i, j int) bool {
+	if valz[i].VotingPower == valz[j].VotingPower {
+		return bytes.Compare(valz[i].Address, valz[j].Address) == -1
+	}
+	return valz[i].VotingPower > valz[j].VotingPower
+}
+
+func (valz ValidatorsByVotingPower) Swap(i, j int) {
+	valz[i], valz[j] = valz[j], valz[i]
+}
+
+// ValidatorsByAddress implements sort.Interface for []*Validator based on
+// the Address field.
 type ValidatorsByAddress []*Validator

-func (valz ValidatorsByAddress) Len() int {
-	return len(valz)
-}
+func (valz ValidatorsByAddress) Len() int { return len(valz) }

 func (valz ValidatorsByAddress) Less(i, j int) bool {
 	return bytes.Compare(valz[i].Address, valz[j].Address) == -1
 }

 func (valz ValidatorsByAddress) Swap(i, j int) {
-	it := valz[i]
-	valz[i] = valz[j]
-	valz[j] = it
+	valz[i], valz[j] = valz[j], valz[i]
 }

 //----------------------------------------
-// for testing

-// RandValidatorSet returns a randomized validator set, useful for testing.
-// NOTE: PrivValidator are in order.
-// UNSTABLE
+// RandValidatorSet returns a randomized validator set (size: +numValidators+),
+// where each validator has a voting power of +votingPower+.
+//
+// EXPOSED FOR TESTING.
 func RandValidatorSet(numValidators int, votingPower int64) (*ValidatorSet, []PrivValidator) {
-	valz := make([]*Validator, numValidators)
-	privValidators := make([]PrivValidator, numValidators)
+	var (
+		valz           = make([]*Validator, numValidators)
+		privValidators = make([]PrivValidator, numValidators)
+	)
+
 	for i := 0; i < numValidators; i++ {
 		val, privValidator := RandValidator(false, votingPower)
 		valz[i] = val
 		privValidators[i] = privValidator
 	}
-	vals := NewValidatorSet(valz)
+
 	sort.Sort(PrivValidatorsByAddress(privValidators))
-	return vals, privValidators
+
+	return NewValidatorSet(valz), privValidators
 }

 ///////////////////////////////////////////////////////////////////////////////
--- a/types/validator_set_test.go
+++ b/types/validator_set_test.go
@@ -929,28 +929,28 @@ func TestValSetUpdatesBasicTestsExecute(t *testing.T) {
 		},
 		{ // voting power changes
 			testValSet(2, 10),
-			[]testVal{{"v1", 11}, {"v2", 22}},
-			[]testVal{{"v1", 11}, {"v2", 22}},
+			[]testVal{{"v2", 22}, {"v1", 11}},
+			[]testVal{{"v2", 22}, {"v1", 11}},
 		},
 		{ // add new validators
-			[]testVal{{"v1", 10}, {"v2", 20}},
-			[]testVal{{"v3", 30}, {"v4", 40}},
-			[]testVal{{"v1", 10}, {"v2", 20}, {"v3", 30}, {"v4", 40}},
+			[]testVal{{"v2", 20}, {"v1", 10}},
+			[]testVal{{"v4", 40}, {"v3", 30}},
+			[]testVal{{"v4", 40}, {"v3", 30}, {"v2", 20}, {"v1", 10}},
 		},
 		{ // add new validator to middle
-			[]testVal{{"v1", 10}, {"v3", 20}},
+			[]testVal{{"v3", 20}, {"v1", 10}},
 			[]testVal{{"v2", 30}},
-			[]testVal{{"v1", 10}, {"v2", 30}, {"v3", 20}},
+			[]testVal{{"v2", 30}, {"v3", 20}, {"v1", 10}},
 		},
 		{ // add new validator to beginning
-			[]testVal{{"v2", 10}, {"v3", 20}},
+			[]testVal{{"v3", 20}, {"v2", 10}},
 			[]testVal{{"v1", 30}},
-			[]testVal{{"v1", 30}, {"v2", 10}, {"v3", 20}},
+			[]testVal{{"v1", 30}, {"v3", 20}, {"v2", 10}},
 		},
 		{ // delete validators
-			[]testVal{{"v1", 10}, {"v2", 20}, {"v3", 30}},
+			[]testVal{{"v3", 30}, {"v2", 20}, {"v1", 10}},
 			[]testVal{{"v2", 0}},
-			[]testVal{{"v1", 10}, {"v3", 30}},
+			[]testVal{{"v3", 30}, {"v1", 10}},
 		},
 	}

@@ -987,19 +987,19 @@ func TestValSetUpdatesOrderIndependenceTestsExecute(t *testing.T) {
 		updateVals []testVal
 	}{
 		0: { // order of changes should not matter, the final validator sets should be the same
-			[]testVal{{"v1", 10}, {"v2", 10}, {"v3", 30}, {"v4", 40}},
-			[]testVal{{"v1", 11}, {"v2", 22}, {"v3", 33}, {"v4", 44}}},
+			[]testVal{{"v4", 40}, {"v3", 30}, {"v2", 10}, {"v1", 10}},
+			[]testVal{{"v4", 44}, {"v3", 33}, {"v2", 22}, {"v1", 11}}},

 		1: { // order of additions should not matter
-			[]testVal{{"v1", 10}, {"v2", 20}},
+			[]testVal{{"v2", 20}, {"v1", 10}},
 			[]testVal{{"v3", 30}, {"v4", 40}, {"v5", 50}, {"v6", 60}}},

 		2: { // order of removals should not matter
-			[]testVal{{"v1", 10}, {"v2", 20}, {"v3", 30}, {"v4", 40}},
+			[]testVal{{"v4", 40}, {"v3", 30}, {"v2", 20}, {"v1", 10}},
 			[]testVal{{"v1", 0}, {"v3", 0}, {"v4", 0}}},

 		3: { // order of mixed operations should not matter
-			[]testVal{{"v1", 10}, {"v2", 20}, {"v3", 30}, {"v4", 40}},
+			[]testVal{{"v4", 40}, {"v3", 30}, {"v2", 20}, {"v1", 10}},
 			[]testVal{{"v1", 0}, {"v3", 0}, {"v2", 22}, {"v5", 50}, {"v4", 44}}},
 	}

@@ -1150,11 +1150,11 @@ func randTestVSetCfg(t *testing.T, nBase, nAddMax int) testVSetCfg {
 		cfg.expectedVals[i-nDel] = cfg.addedVals[i-nBase]
 	}

-	sort.Sort(testValsByAddress(cfg.startVals))
-	sort.Sort(testValsByAddress(cfg.deletedVals))
-	sort.Sort(testValsByAddress(cfg.updatedVals))
-	sort.Sort(testValsByAddress(cfg.addedVals))
-	sort.Sort(testValsByAddress(cfg.expectedVals))
+	sort.Sort(testValsByVotingPower(cfg.startVals))
+	sort.Sort(testValsByVotingPower(cfg.deletedVals))
+	sort.Sort(testValsByVotingPower(cfg.updatedVals))
+	sort.Sort(testValsByVotingPower(cfg.addedVals))
+	sort.Sort(testValsByVotingPower(cfg.expectedVals))

 	return cfg

@@ -1175,25 +1175,25 @@ func TestValSetUpdatePriorityOrderTests(t *testing.T) {

 	testCases := []testVSetCfg{
 		0: { // remove high power validator, keep old equal lower power validators
-			startVals:    []testVal{{"v1", 1}, {"v2", 1}, {"v3", 1000}},
+			startVals:    []testVal{{"v3", 1000}, {"v1", 1}, {"v2", 1}},
 			deletedVals:  []testVal{{"v3", 0}},
 			updatedVals:  []testVal{},
 			addedVals:    []testVal{},
 			expectedVals: []testVal{{"v1", 1}, {"v2", 1}},
 		},
 		1: { // remove high power validator, keep old different power validators
-			startVals:    []testVal{{"v1", 1}, {"v2", 10}, {"v3", 1000}},
+			startVals:    []testVal{{"v3", 1000}, {"v2", 10}, {"v1", 1}},
 			deletedVals:  []testVal{{"v3", 0}},
 			updatedVals:  []testVal{},
 			addedVals:    []testVal{},
-			expectedVals: []testVal{{"v1", 1}, {"v2", 10}},
+			expectedVals: []testVal{{"v2", 10}, {"v1", 1}},
 		},
 		2: { // remove high power validator, add new low power validators, keep old lower power
-			startVals:    []testVal{{"v1", 1}, {"v2", 2}, {"v3", 1000}},
+			startVals:    []testVal{{"v3", 1000}, {"v2", 2}, {"v1", 1}},
 			deletedVals:  []testVal{{"v3", 0}},
 			updatedVals:  []testVal{{"v2", 1}},
-			addedVals:    []testVal{{"v4", 40}, {"v5", 50}},
-			expectedVals: []testVal{{"v1", 1}, {"v2", 1}, {"v4", 40}, {"v5", 50}},
+			addedVals:    []testVal{{"v5", 50}, {"v4", 40}},
+			expectedVals: []testVal{{"v5", 50}, {"v4", 40}, {"v1", 1}, {"v2", 1}},
 		},

 		// generate a configuration with 100 validators,
@@ -1244,7 +1244,7 @@ func verifyValSetUpdatePriorityOrder(t *testing.T, valSet *ValidatorSet, cfg tes
 	//  - they should be at the beginning of valListNewPriority since it is sorted by priority
 	if len(cfg.addedVals) > 0 {
 		addedValsPriSlice := updatedValsPriSorted[:len(cfg.addedVals)]
-		sort.Sort(ValidatorsByAddress(addedValsPriSlice))
+		sort.Sort(ValidatorsByVotingPower(addedValsPriSlice))
 		assert.Equal(t, cfg.addedVals, toTestValList(addedValsPriSlice))

 		//  - and should all have the same priority
@@ -1259,7 +1259,7 @@ func TestValSetUpdateOverflowRelated(t *testing.T) {
 	testCases := []testVSetCfg{
 		{
 			name:         "1 no false overflow error messages for updates",
-			startVals:    []testVal{{"v1", 1}, {"v2", MaxTotalVotingPower - 1}},
+			startVals:    []testVal{{"v2", MaxTotalVotingPower - 1}, {"v1", 1}},
 			updatedVals:  []testVal{{"v1", MaxTotalVotingPower - 1}, {"v2", 1}},
 			expectedVals: []testVal{{"v1", MaxTotalVotingPower - 1}, {"v2", 1}},
 			wantErr:      false,
@@ -1268,9 +1268,9 @@ func TestValSetUpdateOverflowRelated(t *testing.T) {
 			// this test shows that it is important to apply the updates in the order of the change in power
 			// i.e. apply first updates with decreases in power, v2 change in this case.
 			name:         "2 no false overflow error messages for updates",
-			startVals:    []testVal{{"v1", 1}, {"v2", MaxTotalVotingPower - 1}},
+			startVals:    []testVal{{"v2", MaxTotalVotingPower - 1}, {"v1", 1}},
 			updatedVals:  []testVal{{"v1", MaxTotalVotingPower/2 - 1}, {"v2", MaxTotalVotingPower / 2}},
-			expectedVals: []testVal{{"v1", MaxTotalVotingPower/2 - 1}, {"v2", MaxTotalVotingPower / 2}},
+			expectedVals: []testVal{{"v2", MaxTotalVotingPower / 2}, {"v1", MaxTotalVotingPower/2 - 1}},
 			wantErr:      false,
 		},
 		{
@@ -1278,7 +1278,7 @@ func TestValSetUpdateOverflowRelated(t *testing.T) {
 			startVals:    []testVal{{"v1", MaxTotalVotingPower - 2}, {"v2", 1}, {"v3", 1}},
 			deletedVals:  []testVal{{"v1", 0}},
 			addedVals:    []testVal{{"v4", MaxTotalVotingPower - 2}},
-			expectedVals: []testVal{{"v2", 1}, {"v3", 1}, {"v4", MaxTotalVotingPower - 2}},
+			expectedVals: []testVal{{"v4", MaxTotalVotingPower - 2}, {"v2", 1}, {"v3", 1}},
 			wantErr:      false,
 		},
 		{
@@ -1291,7 +1291,7 @@ func TestValSetUpdateOverflowRelated(t *testing.T) {
 				{"v1", MaxTotalVotingPower/2 - 2}, {"v3", MaxTotalVotingPower/2 - 3}, {"v4", 2}},
 			addedVals: []testVal{{"v5", 3}},
 			expectedVals: []testVal{
-				{"v1", MaxTotalVotingPower/2 - 2}, {"v3", MaxTotalVotingPower/2 - 3}, {"v4", 2}, {"v5", 3}},
+				{"v1", MaxTotalVotingPower/2 - 2}, {"v3", MaxTotalVotingPower/2 - 3}, {"v5", 3}, {"v4", 2}},
 			wantErr: false,
 		},
 		{
@@ -1433,18 +1433,21 @@ func (valz validatorsByPriority) Swap(i, j int) {
 }

 //-------------------------------------
-// Sort testVal-s by address.
-type testValsByAddress []testVal

-func (tvals testValsByAddress) Len() int {
+type testValsByVotingPower []testVal
+
+func (tvals testValsByVotingPower) Len() int {
 	return len(tvals)
 }

-func (tvals testValsByAddress) Less(i, j int) bool {
-	return bytes.Compare([]byte(tvals[i].name), []byte(tvals[j].name)) == -1
+func (tvals testValsByVotingPower) Less(i, j int) bool {
+	if tvals[i].power == tvals[j].power {
+		return bytes.Compare([]byte(tvals[i].name), []byte(tvals[j].name)) == -1
+	}
+	return tvals[i].power > tvals[j].power
 }

-func (tvals testValsByAddress) Swap(i, j int) {
+func (tvals testValsByVotingPower) Swap(i, j int) {
 	it := tvals[i]
 	tvals[i] = tvals[j]
 	tvals[j] = it