[Beowulf] is "TCP Short Messages" patch necessary/available for 2.4 kernel?

Jeffrey B. Layton laytonjb at comcast.net
Sun Dec 21 07:55:32 EST 2003


Kervin,

> Thanks Jeffrey,
>
> Is there a kernel config or a /proc file associated with TCP Short 
> Messages?  Or is it enabled by default?  Eg with the patch one had to 
> 'echo 1 > /proc/sys/net/ipv4/tcp_faster_timeouts', but this file is 
> not in 2.4's /proc. 


   To be honest, I can't remember. Josip found that problem way back
in the 2.2 kernel days and I haven't used a 2.2 kernel in about a
year. Here's the original link I have:

http://www.icase.edu/coral/LinuxTCP2.html

Here's a post from Josip explaining that the short message problem
was fixed in the 2.4 series kernels:

http://www.beowulf.org/pipermail/beowulf/2001-August/000988.html

Once again, you don't have to worry about the problem. However, if
you think it's a problem, I'd contact Josip directly and see if he can
help you determine if it is a problem for your code and perhaps how
you can fix it.
   To be honest, it might not be worth fixing. The TCP stack and
networking in the 2.6 kernel are pretty good from what I've heard.
Maybe switching to a 2.6 kernel could help the problem.

> On a related note, does anyone have any TCP options I can turn on to 
> improve the network performance of my beowulf?  I have 50 nodes using 
> channel-bonding on 4 cisco switches. 


   My condolences on using Cisco. I've need had the displeasure
of using them in clusters, but from everything I've heard and
everyone I have spoken with, they're not the best. Difficult
beasts to work with and they don't have good throughput.
   Can you give us some more details? What kind of nodes?
What kind of NICs? Driver version? Switch version? Are you
just trying to get better performance or do you think there's
a problem? What kind of network performance are you getting
now? Have you run things like netpipe and/or netperf between
two nodes? How about testing the NASA Parallel benchmarks
between various combinations of nodes to check performance?
What MPI are you running?
   Also, since you're bonding, have you applied the latest
bonding patches?

http://sourceforge.net/projects/bonding/

You might also join the bonding mailing list if the problem
appears to be with the channel bonding.


Good Luck!

Jeff

P.S. It's Jeff, not Jeffrey. Only RGB calls me Jeffrey and I think
he does it to tweak me. Well, there is my wife when she's
angry with me. Wait, I think I hear some yelling... .

>
>
> Thanks again,
> --Kervin
>
> Jeffrey B. Layton wrote:
>
>> Kervin,
>>
>>   You don't need it for the 2.4 or 2.6 kernels.
>>
>> Enjoy!
>>
>> Jeff
>>
>>> Hello,
>>>
>>> I am upgrading software on a cluster at my college and part of the 
>>> documentation says to patch the kernel with the "TCP Short Messages" 
>>> patch found at http://www.icase.edu/coral/LinuxTCP.html .
>>>
>>> The patch is only available for 2.2 series kernel and none seems to 
>>> be done for the 2.4 kernel.  The contact email on that page bounces 
>>> as well.
>>>
>>> Is this patch still necessary for TCP Short Messages functionality?  
>>> If so where can I find the patch against 2.4?
>>>
>>> Any information would be appreciated,
>>> --Kervin
>>> _______________________________________________
>>> Beowulf mailing list, Beowulf at beowulf.org
>>> To change your subscription (digest mode or unsubscribe) visit 
>>> http://www.beowulf.org/mailman/listinfo/beowulf
>>>
>>
>>
>
>


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