Configurable pacing rate modes via TransportConfig#2543
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stablebits wants to merge 1 commit intoquinn-rs:mainfrom
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Configurable pacing rate modes via TransportConfig#2543stablebits wants to merge 1 commit intoquinn-rs:mainfrom
stablebits wants to merge 1 commit intoquinn-rs:mainfrom
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stablebits
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gretchenfrage
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Add PacingRateMode enum to control rate calculation: - RttDependent: rate = cwnd × 1.25 / RTT (default, standard QUIC) - Fixed: constant bytes/sec rate, ignoring RTT and cwnd - RttDependentWithFloor: max(floor, cwnd × 1.25 / RTT) Fixed and RttDependentWithFloor are useful for latency-sensitive high-RTT connections. With default Quinn's RTT-dependent pacing, cwnd bytes worth of traffic are spread over 80% of the RTT window. This approach doesn't impact overall throughput for large downloads, but it does impact latency. For example, given two connections with RTT of 10ms and 100ms sending 128 transactions, and assuming both congestion and flow control allow this in 1 RTT, it will take 13ms and 130ms (50ms one-way plus 80ms pacing) respectively for these clients to deliver the same data. High-RTT clients are penalized twice: once by RTT, and again by the slower pacing rate.
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Add
PacingRateModeenum to control rate calculation:RttDependent: rate = cwnd × 1.25 / RTT (default, standard QUIC)Fixed: constant bytes/sec rate, ignoring RTT and cwndRttDependentWithFloor: max(floor, cwnd × 1.25 / RTT)FixedandRttDependentWithFloorare useful for latency-sensitive high-RTT connections.With default Quinn's RTT-dependent pacing, cwnd bytes worth of traffic are spread over 80% of the RTT window. This approach doesn't impact overall throughput for large downloads, but it does impact latency. For example, given two connections with RTT of 10ms and 100ms sending 128K of data, and assuming both congestion and flow control allow this in 1 RTT, it will take 13ms (5ms one-way + 8ms pacing) and 130ms (50ms one-way + 80ms pacing) respectively until the last byte is delivered to the server. High-RTT clients are penalized twice: once by RTT, and again by the slower pacing rate.
With fixed-rate pacing (Fixed(rate)), both connections use the same pacing rate, so the delivery spread is independent of RTT.