node: add RTT and bandwidth measurement holders

Signed-off-by: Csaba Kiraly <csaba.kiraly@gmail.com>

codexdht/private/eth/p2p/discoveryv5/node.nim

@@ -20,6 +20,9 @@ import
 
 export stint
 
+const
+  avgSmoothingFactor = 0.9
+
 type
   NodeId* = UInt256
 
@@ -27,6 +30,12 @@ type
     ip*: ValidIpAddress
     port*: Port
 
+  Stats* = object
+    rttMin*: float #millisec
+    rttAvg*: float #millisec
+    bwAvg*: float #bps
+    bwMax*: float #bps
+
   Node* = ref object
     id*: NodeId
     pubkey*: PublicKey
@@ -35,6 +44,7 @@ type
     seen*: bool ## Indicates if there was at least one successful
     ## request-response with this node, or if the nde was verified
     ## through the underlying transport mechanisms.
+    stats*: Stats # traffic measurements and statistics
 
 func toNodeId*(pid: PeerId): NodeId =
   ## Convert public key to a node identifier.
@@ -182,3 +192,21 @@ func shortLog*(address: Address): string =
   $address
 
 chronicles.formatIt(Address): shortLog(it)
+
+# collecting performane metrics
+func registerRtt*(n: Node, rtt: Duration) =
+  ## register an RTT measurement
+  let rttMs = rtt.nanoseconds.float / 1e6
+  n.stats.rttMin =
+    if n.stats.rttMin == 0: rttMs
+    else: min(n.stats.rttMin, rttMs)
+  n.stats.rttAvg =
+    if n.stats.rttAvg == 0: rttMs
+    else: avgSmoothingFactor * n.stats.rttAvg + (1.0 - avgSmoothingFactor) * rttMs
+
+func registerBw*(n: Node, bw: float) =
+  ## register an bandwidth measurement
+  n.stats.bwMax = max(n.stats.bwMax, bw)
+  n.stats.bwAvg =
+    if n.stats.bwAvg == 0: bw
+    else: avgSmoothingFactor * n.stats.bwAvg + (1.0 - avgSmoothingFactor) * bw