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congestion: implemented dynamic packet pacing based on network condit…
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,43 +1,69 @@ | ||
| package congestion | ||
|
|
||
| import "time" | ||
| import ( | ||
| "time" | ||
|
|
||
| const bytesPerToken = 512 | ||
| "github.com/cooldogedev/spectral/internal/protocol" | ||
| ) | ||
|
|
||
| const ( | ||
| minPacingDelay = time.Millisecond * 2 | ||
| minBurstSize = 2 | ||
| maxBurstSize = 10 | ||
| ) | ||
|
|
||
| type Pacer struct { | ||
| capacity int | ||
| tokens int | ||
| interval time.Duration | ||
| lastRefill time.Time | ||
| capacity uint64 | ||
| tokens uint64 | ||
| window uint64 | ||
| rate float64 | ||
| rtt time.Duration | ||
| prev time.Time | ||
| } | ||
|
|
||
| func NewPacer(interval time.Duration, capacity int) *Pacer { | ||
| return &Pacer{ | ||
| capacity: capacity, | ||
| tokens: capacity, | ||
| interval: interval, | ||
| lastRefill: time.Now(), | ||
| } | ||
| func NewPacer() *Pacer { | ||
| return &Pacer{prev: time.Now()} | ||
| } | ||
|
|
||
| func (p *Pacer) Consume(bytes int) time.Duration { | ||
| now := time.Now() | ||
| elapsed := now.Sub(p.lastRefill) | ||
| if elapsed >= p.interval { | ||
| p.tokens = min(p.tokens+int(elapsed/p.interval), p.capacity) | ||
| p.lastRefill = now | ||
| func (p *Pacer) Delay(rtt time.Duration, bytes uint64, window uint64) time.Duration { | ||
| if window != p.window || rtt != p.rtt { | ||
| p.capacity = optimalCapacity(rtt, window) | ||
| p.tokens = min(p.tokens, p.capacity) | ||
| p.window = window | ||
| p.rate = float64(window) / max(rtt.Seconds(), 1) | ||
| p.rtt = rtt | ||
| } | ||
|
|
||
| tokensNeeded := (bytes + bytesPerToken - 1) / bytesPerToken | ||
| if p.tokens >= tokensNeeded { | ||
| p.tokens -= tokensNeeded | ||
| if p.tokens >= bytes { | ||
| return 0 | ||
| } | ||
| return time.Duration(tokensNeeded-p.tokens) * p.interval | ||
|
|
||
| now := time.Now() | ||
| newTokens := p.rate * now.Sub(p.prev).Seconds() | ||
| p.tokens = min(p.tokens+uint64(newTokens), p.capacity) | ||
| p.prev = now | ||
| if p.tokens >= bytes { | ||
| return 0 | ||
| } | ||
| delay := time.Duration(float64(bytes-p.tokens) / p.rate * float64(time.Second)) | ||
| return max(delay, minPacingDelay) | ||
| } | ||
|
|
||
| func (p *Pacer) OnSend(bytes uint64) { | ||
| p.tokens = max(p.tokens-bytes, 0) | ||
| } | ||
|
|
||
| func optimalCapacity(rtt time.Duration, window uint64) uint64 { | ||
| rttNs := max(rtt.Nanoseconds(), 1) | ||
| capacity := (window * uint64(minPacingDelay.Nanoseconds())) / uint64(rttNs) | ||
| return clamp(capacity, minBurstSize*protocol.MaxPacketSize, maxBurstSize*protocol.MaxPacketSize) | ||
| } | ||
|
|
||
| func (p *Pacer) SetInterval(interval time.Duration) { | ||
| if interval > 0 { | ||
| p.interval = interval | ||
| func clamp(value, min, max uint64) uint64 { | ||
| if value < min { | ||
| return min | ||
| } else if value > max { | ||
| return max | ||
| } | ||
| return value | ||
| } |