TSO and FreeBSD vs Linux

[Adrian Chadd]

What's netstat -sp tcp show before/after the test?


-adrian



On 4 September 2013 15:20, David Wolfskill <david at catwhisker.org> wrote:

> On Wed, Sep 04, 2013 at 03:03:12PM -0700, Adrian Chadd wrote:
> > Hiya,
> >
> > David - can you put together a minimal test case that others can
> reproduce?
> > I have a bunch of gige intel NICs that I can try this with when I'm back
> in
> > the office.
> > ...
>
> On NFS client machine (w/ Intel NICs):
> * Ensure that net.inet.tcp.tso=1.
> * Create or gain access to a regular file, size > 2^21 bytes.
> * In my case, "ifconfig em0" showed both TSO4 & VLAN_HWTSO.  I have not
>   experimented to determine whether either or both of those is required
>   -- and in my case, the machine is my desktop here at work: I would
>   prefer to avoid breaking it. :-}
> * Mount a writable file system with adequate free space via NFS.
> * Write the file (e.g., via cp(1)).
>
> If that fails to re-create the problem, perhaps you'll need to have
> another NIC and run IPFW & natd.  Something similar to the stock
> "simple" configuration (/etc/rc.firewall) should do.
>
> During the write, I would run "tcpdump -s 0 -w /tmp/cp.bpf host
> $NFS_server",
> then look at the captured traffic later.  I used wireshark; it pointed
> out the retransmissions.
>
> Peace,
> david
> --
> David H. Wolfskill                              david at catwhisker.org
> Taliban: Evil cowards with guns afraid of truth from a 14-year old girl.
>
> See http://www.catwhisker.org/~david/publickey.gpg for my public key.
>