On Wed, Jan 12, 2022 at 1:02 PM Dave Taht <dave.taht@xxxxxxxxx> wrote: > I would not use the word "latency" in this way, I would just say > potentially reducing > roundtrips... Roundtrips translate directly into latency on high latency links. > and potentially massively increasing packet loss, oversaturating > links, and otherwise > hurting latency for other applications sharing the link, including the > application > that advertised an extreme window like this. The receive window is going to scale up to tcp_rmem[2] with traffic, and packet loss won't stop it. That's around 3MiB on anything that's not embedded these days. My understanding is that congestion control on the sender side deals with packet loss, bottleneck saturation, and packet pacing. This patch only touches the receiving side, letting the client scale up faster if they choose to do so. I don't think any out of the box sender will make use of this, even if we enable it on the receiver, just because the sender's congestion control constraints are lower (like initcwnd=10). Let me know if any of this doesn't look right to you. > This overall focus tends to freak me out somewhat, especially when > faced with further statements that cloudflare is using an initcwnd of 250!??? Congestion window is a learned property, not a static number. You won't get a large initcwnd towards a poor connection. We have a dedicated backbone with different properties.
