feat: auto-tune stream receive window #1868
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This commit adds a basic smoke test using the `test-ficture` simulator, asserting that on a connection with unlimited bandwidth and 50ms round-trip-time Neqo can eventually achieve > 1 Gbit/s throughput. Showcases the potential a future stream flow-control auto-tuning algorithm can have. See mozilla#733.
Previously the stream send and receive window had a hard limit at 1MB. On high latency and/or high bandwidth connections, 1 MB is not enough to exhaust the available bandwidth. Sample scenario: ``` delay_s = 0.05 window_bits = 1 * 1024 * 1024 * 8 bandwidth_bits_s = window_bits / delay_s bandwidth_mbits_s = bandwidth_bits_s / 1024 / 1024 # 160.0 ``` In other words, on a 50 ms connection a 1 MB window can at most achieve 160 Mbit/s. This commit introduces an auto-tuning algorithm for the stream receive window, increasing the window towards the bandwidth-delay product of the connection.
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Previously the stream send and receive window had a hard limit at 1MB. On high latency and/or high bandwidth connections (i.e. large bandwidth-delay product), 1 MB is not enough to exhaust the available bandwidth.
Sample scenario:
In other words, on a 50 ms connection a 1 MB window can at most achieve 160 Mbit/s.
This commit introduces an auto-tuning algorithm for the stream receive window, increasing the window towards the bandwidth-delay product of the connection.
Work in progress for now. Able to transfer >160Mbit/s on a 50ms link already.
Currently implementing the algorithm proposed in #733 (comment). I still have to familiarize myself with the algorithm proposed in #733 (comment). Which ever is chosen, both need the same scaffolding.
Fixes #733.
TODO