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Implement RTT tracking and parallel probing in HyperDHT #230

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164 changes: 163 additions & 1 deletion index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,8 @@ class HyperDHT extends DHT {

super({ ...opts, port, bootstrap, nodes, filterNode })

const { router, relayAddresses, persistent } = defaultCacheOpts(opts)
const { router, relayAddresses, nodeRTT, connectionCache, directConnectionCache, persistent } =
defaultCacheOpts(opts)

this.defaultKeyPair = opts.keyPair || createKeyPair(opts.seed)
this.listening = new Set()
Expand All @@ -46,6 +47,12 @@ class HyperDHT extends DHT {
this._validatedLocalAddresses = new Map()
this._relayAddressesCache = new Cache(relayAddresses)

this._nodeRTT = new Cache(nodeRTT)

this._connectionCache = new Cache(connectionCache)

this._directConnectionCache = new Cache(directConnectionCache)

this._deferRandomPunch = !!opts.deferRandomPunch
this._lastRandomPunch = this._deferRandomPunch ? Date.now() : 0
this._connectable = true
Expand All @@ -65,6 +72,63 @@ class HyperDHT extends DHT {
if (!this.online) return
for (const server of this.listening) server.notifyOnline()
})

this._rttWarmupInterval = null
if (opts.preWarmRTT !== false) {
this._startRTTWarmup()
}

this.parallelProbing = opts.parallelProbing !== false
}

_startRTTWarmup() {
if (this._rttWarmupInterval) return

this._rttWarmupInterval = setInterval(() => {
if (this.destroyed || !this.online) return

// Sample up to 10 random nodes for RTT measurement
const nodes = []
if (this.nodes && this.nodes.latest) {
let count = 0
for (let node = this.nodes.latest; node && count < 10; node = node.prev) {
if (node.host && node.port) {
nodes.push(node)
count++
}
}
}

for (const node of nodes) {
const key = `${node.host}:${node.port}`
const stats = this._nodeRTT.get(key)
const needsUpdate = !stats || Date.now() - stats.lastUpdate > 60000 // Update if older than 60s

if (needsUpdate) {
// Measure RTT in background (don't await)
const startTime = process.hrtime.bigint()
this.ping({ host: node.host, port: node.port }).then(
() => {
const endTime = process.hrtime.bigint()
const rtt = Number(endTime - startTime) / 1_000_000
if (rtt > 0 && rtt < 10000) {

this.updateNodeRTT(node, rtt)
}
},
() => {
}
)
}
}
}, 30000)
}

_stopRTTWarmup() {
if (this._rttWarmupInterval) {
clearInterval(this._rttWarmupInterval)
this._rttWarmupInterval = null
}
}

connect(remotePublicKey, opts) {
Expand Down Expand Up @@ -119,9 +183,104 @@ class HyperDHT extends DHT {
if (this._persistent) this._persistent.destroy()
await this.rawStreams.clear()
await this._socketPool.destroy()
this._stopRTTWarmup()
this._nodeRTT.clear()
this._connectionCache.clear()
this._directConnectionCache.clear()
await super.destroy()
}


getNodeRTT(node) {
if (!node) return null
const host = node.host || (node.address && node.address.host)
const port = node.port || (node.address && node.address.port)
if (!host || !port) return null

const key = `${host}:${port}`
const stats = this._nodeRTT.get(key)
return stats ? stats.srtt : null
}


updateNodeRTT(node, rtt) {
if (!node || !rtt || rtt <= 0) return

const host = node.host || (node.address && node.address.host)
const port = node.port || (node.address && node.address.port)
if (!host || !port) return

const key = `${host}:${port}`

const alpha = 0.125 // Weight for SRTT
const beta = 0.25 // Weight for RTTVAR

if (!this._nodeRTT.has(key)) {
// First measurement
this._nodeRTT.set(key, {
srtt: rtt,
rttvar: rtt / 2, // Initial variance estimate
samples: 1,
lastUpdate: Date.now()
})
} else {
const stats = this._nodeRTT.get(key)

stats.rttvar = (1 - beta) * stats.rttvar + beta * Math.abs(stats.srtt - rtt)

stats.srtt = (1 - alpha) * stats.srtt + alpha * rtt

stats.samples++
stats.lastUpdate = Date.now()
}
}


sortNodesByRTT(nodes) {
return nodes
.map((node) => ({
node,
rtt: this.getNodeRTT(node) || Infinity
}))
.sort((a, b) => a.rtt - b.rtt)
.map((item) => item.node)
}


getAverageRTT() {
if (!this._nodeRTT) return null

let totalRTT = 0
let count = 0
for (const stats of this._nodeRTT.values()) {
if (stats.srtt && stats.srtt > 0) {
totalRTT += stats.srtt
count++
}
}

return count > 0 ? totalRTT / count : null
}


getRTTBasedTimeout(baseTimeout = 10000, minMultiplier = 0.9, maxMultiplier = 1.5) {
const avgRTT = this.getAverageRTT()
if (!avgRTT) return baseTimeout

// Only optimize timeout if we have very fast RTT (< 100ms)
// For slower networks, keep the base timeout to avoid premature timeouts
if (avgRTT < 100) {
// For fast networks, use 10x RTT as timeout (very conservative)
const rttBasedTimeout = avgRTT * 10
const minTimeout = baseTimeout * minMultiplier
const maxTimeout = baseTimeout * maxMultiplier
return Math.max(minTimeout, Math.min(maxTimeout, rttBasedTimeout))
}

// For slower networks, don't reduce timeout - keep base
return baseTimeout
}

async validateLocalAddresses(addresses) {
const list = []
const socks = []
Expand Down Expand Up @@ -593,6 +752,9 @@ function defaultCacheOpts(opts) {
forwards: { maxSize, maxAge }
},
relayAddresses: { maxSize: Math.min(maxSize, 512), maxAge: 0 },
nodeRTT: { maxSize: Math.min(maxSize, 2048), maxAge: 3600000 },
connectionCache: { maxSize: Math.min(maxSize, 1024), maxAge: 60000 },
directConnectionCache: { maxSize: Math.min(maxSize, 1024), maxAge: 300000 },
persistent: {
records: { maxSize, maxAge },
refreshes: { maxSize, maxAge },
Expand Down
50 changes: 46 additions & 4 deletions lib/announcer.js
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Original file line number Diff line number Diff line change
Expand Up @@ -112,7 +112,22 @@ module.exports = class Announcer {
const pings = []

for (const node of this._serverRelays[2].values()) {
pings.push(this.dht.ping(node))
const startTime = process.hrtime.bigint()
const pingPromise = this.dht.ping(node).then(
(res) => {
// Track RTT for relay nodes
const endTime = process.hrtime.bigint()
const rtt = Number(endTime - startTime) / 1_000_000 // ms
if (this.dht.updateNodeRTT) {
this.dht.updateNodeRTT(node, rtt)
}
return res
},
(err) => {
throw err
}
)
pings.push(pingPromise)
}

const active = await resolved(pings)
Expand Down Expand Up @@ -167,7 +182,7 @@ module.exports = class Announcer {
if (this.stopped || this.suspended) return

const ann = []
const replies = pickBest(q.closestReplies)
const replies = pickBest(q.closestReplies, this.dht)

const relays = []
const relayAddresses = []
Expand Down Expand Up @@ -295,8 +310,35 @@ function resolved(ps) {
})
}

function pickBest(replies) {
// TODO: pick the ones closest to us RTT wise
function pickBest(replies, dht) {
if (!replies || replies.length === 0) return []

if (dht && dht.sortNodesByRTT) {
const nodeToMsg = new Map()
const nodes = []

for (const msg of replies) {
if (msg.from) {
nodes.push(msg.from)
const key = `${msg.from.host}:${msg.from.port}`
nodeToMsg.set(key, msg)
}
}

if (nodes.length > 0) {
const sortedNodes = dht.sortNodesByRTT(nodes)

const sortedMsgs = []
for (const node of sortedNodes) {
const key = `${node.host}:${node.port}`
const msg = nodeToMsg.get(key)
if (msg) sortedMsgs.push(msg)
}

return sortedMsgs.slice(0, 3)
}
}

return replies.slice(0, 3)
}

Expand Down
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