[nycbug-talk] TCP tuning between FreeBSD and Vista

[Charles Sprickman]

On Sun, 2 Nov 2008, Jonathan wrote:

> OK I'm stuck :(
>
> I've been playing with it for two days and I can't for the life of me
> get more than 7% utilization of a gigabit link between my laptop and my
> file server.  I've gone through man tuning as well as a great deal of
> Google searching and here are the settings I've tried tweaking with
> their current values.  My current testing is transmitting from FreeBSD
> to Vista so I've not messed with receive specific settings on BSD or the
> transmit specific on Vista.

What version of FreeBSD?  In 7.x, they enabled SCTP, which may or may not 
have any bearing on this.

Are other non-vista machines capable of getting closer to line rate?

Charles

> FreeBSD
> net.inet.tcp.rfc1323: 1
> net.inet.tcp.sendspace: 1048576
> net.inet.tcp.recvspace: 1048576
> net.inet.tcp.delayed_ack: 1
> net.inet.tcp.sendbuf_max: 262144
>
> Vista
> TCP Global Parameters
> ----------------------------------------------
> Receive-Side Scaling State          : enabled
> Chimney Offload State               : enabled
> Receive Window Auto-Tuning Level    : normal
> Add-On Congestion Control Provider  : ctcp
> ECN Capability                      : disabled
> RFC 1323 Timestamps                 : enabled
>
> I even did a wireshark dump which looks fine other than the fact I can't
> get higher than 7% Trimmed wireshark trace start follows
>
> [SYN] Seq=0 Win=65535 Len=0 MSS=1460 WS=9
> [SYN, ACK] Seq=0 Ack=1 Win=8192 Len=0 MSS=1460 WS=8
> [ACK] Seq=1 Ack=1 Win=1049600 Len=0
>
> The window stays at 1049600 for the remainder of the connection.
>
> Am I missing something obvious or does anyone have any suggestions to
> try as I'm getting rather frustrated at this point.
>
> Thanks,
> Jonathan Stewart
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