Testing the GNIC-II (Hamachi) gigabit NIC

[Jan Rychter]

>>>>> "Jes" == Jes Sorensen <Jes.Sorensen@cern.ch>:
>>>>> "Alan" == Alan Cox <alan@lxorguk.ukuu.org.uk> writes:
 >>> to recognize that there is a 64-bit card in a 32-bit PCI slot), I'm
 >>> trying to do some benchmarks. The cards are in a back-to-back
 >>> configuration between an Alpha-533 and a PentiumII-266.
 >>> 
 >>> Are there any TCP settings I can possibly tweak to improve TCP
 >>> performance on large file transfers ?

 Alan> The biggest thing you want to do is to use 8K packets if the card
 Alan> can support it, instead of 1500 byte frames for gig-E as
 Alan> 'aggregation media'

 Jes> Right, for me with the Alteon card, the performance increases from
 Jes> like 28MB/sec to around 90MB/sec in a P2 400MHz 440BX (PCI
 Jes> 32/33)box when going from 1500 byte frames to 9K ones.

 Jes> However, I would be interested to hear what kind of performance
 Jes> you get on 1500 byte frames.

31MB/s and that's doing ftp transfers of a large file (~80MB) to
/dev/null. The transfers were from an Alpha 533 (128MB RAM) to a
Pentium-II 266.

31MB/s TCP is impressive in itself, but I think both the card and the
machines are capable of more.

I don't have the cards available at the moment, but will have them again 
in about two-three weeks. I will try larger frames then, if only this is 
possible (it can't be done simply by setting the interface MTU).

--J.
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