[viewchange] update view ID slower than view change timeout

so that node init view change at different timeslot can converge on the
same view ID

Signed-off-by: Leo Chen <leo@harmony.one>

consensus/config.go

@@ -6,6 +6,10 @@ import "time"
 const (
 	// default timeout configuration is shorten to 45 seconds as the consensus is 5s
 	viewChangeTimeout = 45
+	// viewChangeSlot means every 90 seconds, the view change ID will be advanced.
+	// so that the nodes init view change process within the 90 seconds range will
+	// be have the same view change ID
+	viewChangeSlot = 90
 	// The duration of viewChangeTimeout for each view change
 	viewChangeDuration time.Duration = viewChangeTimeout * time.Second
 

consensus/view_change.go

@@ -133,7 +133,7 @@ func (consensus *Consensus) getNextViewID() (uint64, time.Duration) {
 		return consensus.fallbackNextViewID()
 	}
 	// diff only increases
-	diff := uint64((curTimestamp - blockTimestamp) / viewChangeTimeout)
+	diff := uint64((curTimestamp - blockTimestamp) / viewChangeSlot)
 	nextViewID := diff + lastBlockViewID
 
 	consensus.getLogger().Info().