Hello. I spent quite a bit of time looking at this under NetBSD-5 and discovered that the default ssh settings, along with the default tcp network settings precluded the adaptive network performance from working. As a result, I've added the following lines to the ssh configs as well as the sysctl.conf files on the NetBSD-5 hosts we manage. As faras I've been able to tell, we've been able to realize good performance gains as a result of these changes. Unless there have been a lot of regressions, I have no reason to believe that these settings won't yield similar performance improvements under NetBSD-7 and NetBSD-8.
Here are the fixes I came up with. </etc/sysctl.conf> # Improves TCP performance significantly with ssh. net.inet.tcp.recvbuf_auto=1 net.inet.tcp.sendbuf_auto=1 net.inet.tcp.sendbuf_max=16777216 net.inet.tcp.recvbuf_max=16777216 <ssh.conf changes> # Put the following lines in both /etc/ssh/ssh_config # and /etc/ssh/sshd_config #Enable High Performance Networking options (BB 12/27/2010) #Turn on HPN features HPNDisabled no #Allow 5MB of ssh window buffer HPNBufferSize 5000 #Enable dynamic window sizing of SSH buffers #You must have tcp autotuning turned on in the kernel for this to work TcpRcvBufPoll yes
