[Beowulf] Full-duplex performance problems with Intel Gigabit
Bogdan.Costescu at iwr.uni-heidelberg.de
Thu Aug 4 07:00:57 PDT 2005
On Thu, 4 Aug 2005, Felix Rauch Valenti wrote:
> Are there any known performance problems with Intel 82541GI/PI or
> 82547GI Gigabit Ethernet cards?
The 82541GI/PI cards are normally connected to a 32-bit, 33MHz PCI
bus, which limits the total transfer speed; 2 x 50Mbyte/s is
reasonably close to the maximum.
On quick tests made here with 2 nodes each with a single CPU P4 3.2GHz
and a 82541GI/PI card, I get about 90Mbyte/s single flow versus about
2x48Mbyte/s when transferring simultaneously in both directions.
However the double flow is also associated with a high interrupt rate
(44K/s) and context switches (59K/s), which might also act as limits.
(tests done with nc < /dev/zero and nc > /dev/null, no Jumbo frames;
measurements with dstat http://dag.wieers.com/home-made/dstat/)
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E-mail: Bogdan.Costescu at IWR.Uni-Heidelberg.De
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