[email protected] (z411) writes: >UDP speeds are great, but NetBSD specifically has an issue with >TCP/HTTP. The speed seems to be capped to exactly 986 KB/s and it's very >unstable (congestion handling issues I assume).
>I tried tuning the following: >net.inet.tcp.recvbuf_auto=1 >net.inet.tcp.sendbuf_auto=1 >net.bpf.jit=1 >net.bpf.maxbufsize=4194304 >net.inet.tcp.sendbuf_max=16777216 >net.inet.tcp.recvbuf_max=16777216 >net.inet.ip.ifq.maxlen=4096 >net.inet.tcp.mssdflt=1072 You need to increase kern.sbmax too, this is a global limit on the socket buffer size. The default is 256kB, so at 200ms RTT you are limited to about 256kB/200ms ~ 10Mbit/s. If you have many connections you may also need to increase kern.somaxkva that limits how much memory can be allocated to the network in total. >Since post-tuning it's very stable I don't think it's about congestion >anymore - but I'm not sure why I'm hitting this hard cap, even after >increasing the buffer sizes. Could it be that NetBSD is not increasing >the window size? NetBSD will grow the window and has window scaling enabled by default. However, it is very slow growing the send window after a congestion event.
