Poor Samba throughput on 6.0

[Robert Watson]

On Wed, 9 Nov 2005, Mike Jakubik wrote:

> I have done many tests to try to determine the poor performance on my 
> systems (FreeBSD-current connected directly to Windows XP via identical 
> Intel Pro 1000 cards) and my only conclusion is that Samba on FreeBSD 
> when talking to a Windows box is simply fubared. Im willing to bet thats 
> not the case on Linux. I can get great speeds (~30MB/s) using ftp 
> between the machines, but when i use Samba, i get a maximum of 11MB/s. I 
> have tried playing with mtu size, samba options, polling, but there does 
> not seem to be any visible bottlenecks, its just simply slow. It would 
> be great if someone could get to the bottom of this, its quite 
> frustrating.

There are a number of TCP related configuration frobs on FreeBSD.  It 
would be quite interesting to know how modifying each of the following 
settings affects Samba performance:

net.inet.tcp.delayed_ack
net.inet.tcp.sack.enable
net.inet.tcp.inflight.enable

There has been recent evidence that the inflight bandwidth calculation is 
having problems generating stable performance at high bandwidth and low 
latency, so I might try that one first.

Robert N M Watson