[Beowulf] always raw

Sean Dilda agrajag at dragaera.net
Fri Sep 3 06:15:42 PDT 2004

On Wed, 2004-09-01 at 06:59, 050675 at student.unife.it wrote:

> Bytes received: 552000000
> Time elapsed: 5.7 sec
> Throughput: 91 Mbytes/sec
> Now, the same experiment reproduced with raw ethernet illustrates a
> throughput of 87 Mbytes/sec and the time elapsed is 6.3 sec. How is it
> possible? Raw ethernet doesn't need retransmission, ack, etc. like tcp,
> but here tcp seems to be the best. I don't understand.

What is your networking setup like?  Using two Dell PowerEdge 1750s with
broadcom chips in them connected over a Dell PowerConnect 5224 I can
push 112MB/s over the wire (as reported by ttcp).  If I enable jumbo
frames, I can get that up to 117MB/s.   I'm assuming you're using
gigabit to get numbers that high, but they still seem kinda low.

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