reverse dht ownership order from predecessor to successor, this plays nicer with the default 0 bits in unknown node IDs

This commit is contained in:
Arceliar 2018-10-21 18:15:04 -05:00
parent 5e3959f1d0
commit 253861ebd3
2 changed files with 11 additions and 35 deletions

View File

@ -11,7 +11,7 @@ import (
"time" "time"
) )
const dht_lookup_size = 4 const dht_lookup_size = 16
// dhtInfo represents everything we know about a node in the DHT. // dhtInfo represents everything we know about a node in the DHT.
// This includes its key, a cache of it's NodeID, coords, and timing/ping related info for deciding who/when to ping nodes for maintenance. // This includes its key, a cache of it's NodeID, coords, and timing/ping related info for deciding who/when to ping nodes for maintenance.
@ -75,43 +75,16 @@ func (t *dht) reset() {
} }
// Does a DHT lookup and returns up to dht_lookup_size results // Does a DHT lookup and returns up to dht_lookup_size results
// If allowWorse = true, begins with best know predecessor for ID and works backwards, even if these nodes are worse predecessors than we are, to be used when intializing searches
// If allowWorse = false, begins with the best known successor for ID and works backwards (next is predecessor, etc, inclusive of the ID if it's a known node)
func (t *dht) lookup(nodeID *NodeID, everything bool) []*dhtInfo { func (t *dht) lookup(nodeID *NodeID, everything bool) []*dhtInfo {
results := make([]*dhtInfo, 0, len(t.table)) results := make([]*dhtInfo, 0, len(t.table))
for _, info := range t.table { for _, info := range t.table {
results = append(results, info) results = append(results, info)
} }
sort.SliceStable(results, func(i, j int) bool { sort.SliceStable(results, func(i, j int) bool {
return dht_ordered(results[j].getNodeID(), results[i].getNodeID(), nodeID) return dht_ordered(nodeID, results[i].getNodeID(), results[j].getNodeID())
}) })
if len(results) > dht_lookup_size { if len(results) > dht_lookup_size {
//results = results[:dht_lookup_size] //FIXME debug results = results[:dht_lookup_size]
}
return results
}
func (t *dht) old_lookup(nodeID *NodeID, allowWorse bool) []*dhtInfo {
var results []*dhtInfo
var successor *dhtInfo
sTarget := t.nodeID.next()
for infoID, info := range t.table {
if true || allowWorse || dht_ordered(&t.nodeID, &infoID, nodeID) {
results = append(results, info)
} else {
if successor == nil || dht_ordered(&sTarget, &infoID, successor.getNodeID()) {
successor = info
}
}
}
sort.SliceStable(results, func(i, j int) bool {
return dht_ordered(results[j].getNodeID(), results[i].getNodeID(), nodeID)
})
if successor != nil {
results = append([]*dhtInfo{successor}, results...)
}
if len(results) > dht_lookup_size {
//results = results[:dht_lookup_size] //FIXME debug
} }
return results return results
} }
@ -350,8 +323,9 @@ func (t *dht) getImportant() []*dhtInfo {
} }
// Sort them by increasing order in distance along the ring // Sort them by increasing order in distance along the ring
sort.SliceStable(infos, func(i, j int) bool { sort.SliceStable(infos, func(i, j int) bool {
// Sort in order of successors // Sort in order of predecessors (!), reverse from chord normal, becuase it plays nicer with zero bits for unknown parts of target addresses
return dht_ordered(&t.nodeID, infos[i].getNodeID(), infos[j].getNodeID()) return dht_ordered(infos[j].getNodeID(), infos[i].getNodeID(), &t.nodeID)
//return dht_ordered(&t.nodeID, infos[i].getNodeID(), infos[j].getNodeID())
}) })
// Keep the ones that are no further than the closest seen so far // Keep the ones that are no further than the closest seen so far
minDist := ^uint64(0) minDist := ^uint64(0)
@ -377,7 +351,8 @@ func (t *dht) isImportant(ninfo *dhtInfo, important []*dhtInfo) bool {
if dist < minDist { if dist < minDist {
minDist = dist minDist = dist
} }
if dht_ordered(&t.nodeID, ninfo.getNodeID(), info.getNodeID()) && ndist <= minDist { //if dht_ordered(&t.nodeID, ninfo.getNodeID(), info.getNodeID()) && ndist <= minDist {
if dht_ordered(info.getNodeID(), ninfo.getNodeID(), &t.nodeID) && ndist <= minDist {
// This node is at least as close in both key space and tree space // This node is at least as close in both key space and tree space
return true return true
} }

View File

@ -113,11 +113,12 @@ func (s *searches) addToSearch(sinfo *searchInfo, res *dhtRes) {
sort.SliceStable(sinfo.toVisit, func(i, j int) bool { sort.SliceStable(sinfo.toVisit, func(i, j int) bool {
// Should return true if i is closer to the destination than j // Should return true if i is closer to the destination than j
// FIXME for some reason it works better backwards, why?! // FIXME for some reason it works better backwards, why?!
return dht_ordered(sinfo.toVisit[j].getNodeID(), sinfo.toVisit[i].getNodeID(), &res.Dest) //return dht_ordered(sinfo.toVisit[j].getNodeID(), sinfo.toVisit[i].getNodeID(), &res.Dest)
return dht_ordered(&res.Dest, sinfo.toVisit[i].getNodeID(), sinfo.toVisit[j].getNodeID())
}) })
// Truncate to some maximum size // Truncate to some maximum size
if len(sinfo.toVisit) > search_MAX_SEARCH_SIZE { if len(sinfo.toVisit) > search_MAX_SEARCH_SIZE {
//sinfo.toVisit = sinfo.toVisit[:search_MAX_SEARCH_SIZE] sinfo.toVisit = sinfo.toVisit[:search_MAX_SEARCH_SIZE]
} }
} }