try another peer sorting metric. fix bug in when findproviders returns

kpeerset/metrics.go

 package kpeerset
 
 import (
+	"math/big"
 	"sort"
 	"time"
 
@@ -20,7 +21,12 @@ type peerLatencyMetricList []peerLatencyMetric
 func (p peerLatencyMetricList) Len() int { return len(p) }
 func (p peerLatencyMetricList) Less(i, j int) bool {
 	pm1, pm2 := p[i], p[j]
+	return calculationLess(pm1, pm2)
+}
+func (p peerLatencyMetricList) Swap(i, j int)           { p[i], p[j] = p[j], p[i] }
+func (p peerLatencyMetricList) GetPeerID(i int) peer.ID { return p[i].peer }
 
+func less(pm1, pm2 *peerLatencyMetric) bool {
 	p1Connectedness, p2Connectedness := pm1.connectedness, pm2.connectedness
 	p1Latency, p2Latency := pm1.latency, pm2.latency
 
@@ -58,8 +64,36 @@ func (p peerLatencyMetricList) Less(i, j int) bool {
 
 	return pm1.metric.Cmp(pm2.metric) == -1
 }
-func (p peerLatencyMetricList) Swap(i, j int)           { p[i], p[j] = p[j], p[i] }
-func (p peerLatencyMetricList) GetPeerID(i int) peer.ID { return p[i].peer }
+
+func calculationLess(pm1, pm2 peerLatencyMetric) bool {
+	return calc(pm1).Cmp(calc(pm2)) == -1
+}
+
+func calc(pm peerLatencyMetric) *big.Int {
+	var c int64
+	switch pm.connectedness {
+	case network.Connected:
+		c = 1
+	case network.CanConnect:
+		c = 5
+	case network.CannotConnect:
+		c = 10000
+	default:
+		c = 20
+	}
+
+	l := int64(pm.latency)
+	if l <= 0 {
+		l = int64(time.Second) * 10
+	}
+
+	res := big.NewInt(c)
+	tmp := big.NewInt(l)
+	res.Mul(res, tmp)
+	res.Mul(res, pm.metric)
+
+	return res
+}
 
 var _ SortablePeers = (*peerLatencyMetricList)(nil)
 

routing.go

@@ -608,7 +608,7 @@ func (dht *IpfsDHT) findProvidersAsyncRoutine(ctx context.Context, key multihash
 			return peers, nil
 		},
 		func(peerset *kpeerset.SortedPeerset) bool {
-			return ps.Size() > count
+			return ps.Size() >= count
 		},
 	)