amd64 tcp weirdness
jacco at jbraat.demon.nl
Tue Dec 5 09:31:47 PST 2006
i'm using RELENG_6 on amd64 and have trouble with downloads.
I think this is related to the window scaling feature.
generates 5 packets for the HTTP GET request, and lots of DUP ACK packets.
there is no Window Scale option in the SYN ACK reply.
generates only 1 packet for the HTTP GET request.
Window Scale = 0 in the SYN ACK reply
on i386 also RELENG_6 no such differences.
setting net.inet.tcp.recvspace to a smaller value also gives normal results.
I noticed this behavior because my Realtek 8168B got stuck on some
websites, a Intel Pro/1000 did not. With both cards the tcpdumps are
More information about the freebsd-amd64