On Thu, Jan 13, 2022 at 9:44 PM Dave Taht <dave.taht@xxxxxxxxx> wrote: > Yes, but with the caveats below. I'm fine with you just saying round trips, > and making this api possible. > > It would comfort me further if you could provide an actual scenario. The actual scenario is getting a response as quickly as possible on a fresh connection across long distances (200ms+ RTT). If an RPC response doesn't fit into the initial 64k of rcv_ssthresh, we end up requiring more roundrips to receive the response. Some customers are very picky about the latency they measure and cutting the extra roundtrips made a very visible difference in the tests. > See also: > > https://datatracker.ietf.org/doc/html/rfc6928 > > which predates packet pacing (are you using sch_fq?) We are using fq and bbr. > > Congestion window is a learned property, not a static number. You > > won't get a large initcwnd towards a poor connection. > > initcwnd is set globally or on a per route basis. With TCP_BPF_IW the world is your oyster.
