FreeBSD 4.x and OS-X tcp performance

[Charles Sprickman]

On Fri, 4 Mar 2005, Bill Vermillion wrote:

> "Ang utong ko ay sasabog sa sarap!" exclaimed Charles Sprickman
> while reading this message on Fri, Mar 04, 2005 at 18:43
> and then responded with:
>
>> On Fri, 4 Mar 2005, Darcy Buskermolen wrote:
>
>>> On Friday 04 March 2005 14:34, Charles Sprickman wrote:
>>>> Howdy,
>
>>>> Sorry to bring what seems like a simple issue up here.
>>>> I had been blaming slow afp filesharing between my OS-X
>>>> (10.3.8 and previous) and FreeBSD 4.x boxes on netatalk's
>>>> afp implementation for some time. Not too long ago I got
>>>> frustrated with this and tried smb and then ftp. On a simple
>>>> 10/100 network, and even with just a crossover between two
>>>> boxes it seems that any tcp transfer tops out at around
>>>> 250KB/s.
>
>>>> On the same network using the same switch I can get near
>>>> Oline-rate to an penBSD box and to another OS-X box.
>
>>>> If I use nfs and force udp as the transport, I *do* get near
>>>> line-rate between OS-X and FBSD.
>
>>>> My 5.3 box is tanked at the moment, so I cannot tell if the
>>>> problem happens there as well. I do have a full ADC account,
>>>> so I will be testing with the latest Tiger preview shortly,
>>>> and the ADC access does give me a decent bug reporting
>>>> facility if the fault lies within the OS-X tcp stack.
>
>>>> I'm no tcpdump wizard, would anyone care to help me track this down?
>
>>> I'd start with ensureing your nic's media options are properly
>>> set (I've seen this exact behavior during duplex mismatches)
>
>> Yep, I wouldn't have come here without checking all the basics.  I should
>> also add that given three machines in my standard config I get the
>> following results which will also help rule out cabling/speed/duplex
>> issues:
>
>> os-x <-> obsd - good
>> os-x <-> fbsd - bad
>> obsd <-> fbsd - good
>> os-x <-> os-x - good

> I do suspect duplex problems.   He was connecting to one of our
> Cicso switches and Cisco has some extensive docs on some
> configuration problems.  Part of it comes from when some vendors
> decided to add their own features and violated standards.

I'd really like to move past the duplex issues.  I'm very very familiar 
with that and already chased my tail on that one here and in my many years 
of working at an ISP.  I did a back-to-back test with speed/duplex locked 
and I get the same result.  All the switch ports are running clean - no 
errors, which is something you'd normally see if autoneg failed.

Plus if you look at the matrix above, you can see that every other 
combination in my "normal" config works.  If there were a duplex problem, 
I would be seeing it either from OS-X <-> OBSD or FBSD <-> OBSD.  It also 
probably wouldn't allow me to get really fast UDP NFS between the boxes.

For fun I'm going to post a full tcpdump of an ftp session from one box to 
the other, maybe someone can spot something there?  It's attached and 
bzip'd.  It's a tcpdump of both hosts transferring a 1MB tarfile.

Thanks!

Charles

> http://www.cisco.com/warp/public/473/46.html
>
> This is the link I saved from awhile back.  I hope it is
> still valid.
>
> But problems like this usually come from one side or the other not
> properly responding to auto-negotiation as documented.  When
> auto-neg fails at least one side will go to half-duplex, and with
> the other in fdx then you usually only see throughput of
> about 10% of normal because of data being sent back on a line that
> the fdx line thinks is clear to send upon.



> Bill
>
>
> -- 
> Bill Vermillion - bv @ wjv . com
>
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