slowdowns with MTU > 8k

[Greg Dickie]

Hi Chris,

I don't think so, so what I just posted. We can do a ping of 9014 and this MTU
is supposed to be supported by the switch and all the other NICs. Every other
test we do we see a benefit in the bigger MTU, it just seems like a samba
specific thing. I just responded to a post by Anton because from some tests I
did yesterday it appears to be sendfile related....

Thanks for the reponse though it was a good idea,
Greg

On 25-Jul-01 Christopher R. Hertel wrote:
> Is it just Samba?
> 
> I'm wondering if some device (your GIGE interface card, some intermediate 
> switch, something) has a lower limit and could be splitting your packets 
> in half on you.  That would slow things down a bit.
> 
> Chris -)-----
> 
>> Hi,
>> 
>>   We are playing with gigabit ethernet and we get quite good performance
>> when the MTU is set around 8k. If we set it at 9014 (max MTU on the switch
>> we use) the throughput from samba gets cut in half. Tried playing with
>> "max xmit" but no effect.
>> 
>>   Anyone have any ideas what the problem could be or have any tools to
>> dump the profile shared memory?
>> 
>> Thanks,
>> Greg
>> 
>> ---------------------------------------------------------------------
>> Greg Dickie
>> just a guy
>> greg at discreet.com
>> 
>> 
> 
> 
> -- 
> Christopher R. Hertel -)-----                   University of Minnesota
> crh at nts.umn.edu              Networking and Telecommunications Services
> 
>     Ideals are like stars; you will not succeed in touching them
>     with your hands...you choose them as your guides, and following
>     them you will reach your destiny.  --Carl Schultz

---------------------------------------------------------------------
Greg Dickie
just a guy
greg at discreet.com