FastE NIC Recommendation

Steffen Persvold sp at scali.com
Mon Nov 18 08:54:54 EST 2002


On Mon, 18 Nov 2002, Trent Piepho wrote:

> On Mon, 18 Nov 2002, Steffen Persvold wrote:
> > The Intel e1000 (which is in the Linux kernel tree btw.) has a ping-pong/2 
> > latency of about 25us on a decent Platform (Xeon, E7500 chipset). The 
> > Broadcom 5700 series (with the tg3 driver) has approx. 30us ping-pong/2 
> > latency on a ServerWorks GC-LE chipset (also Xeon processors). _But_ if 
> > you try e1000 on a AMD 760 MPX chipset for instance, the latency increases 
> > to 65 us ping-pong/2. YMMV.
> 
> Is that an interaction between the 760MPX and the e1000, or typical for the
> 760MPX?  ie. does the broadcom 5700 also have high latency with AMD chipsets?
> 

Unfortunately I haven't tested the Broadcom adapters on 760 MPX yet 
(actually the only reason I've tested Broadcom at all was that it was 
onboard on our Dell 2650s). However, I've tested e1000 on PentiumIII 
w/ServerWorks HE-SL chipset, and there the latency was 30us. Maybe 
there's something with the AMD IOAPICs ? From what I've seen it seem like 
most of the latency is produced in the receiving node IRQ processing.

Regards,
 -- 
  Steffen Persvold   |       Scali AS      
 mailto:sp at scali.com |  http://www.scali.com
Tel: (+47) 2262 8950 |   Olaf Helsets vei 6
Fax: (+47) 2262 8951 |   N0621 Oslo, NORWAY

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