decreasing interrupt CPU load

Uwe Doering gemini at
Wed Oct 20 13:16:43 PDT 2004

Oleg Gawriloff wrote:
> Hello, Eric!
> You wrote to "Oleg Gawriloff" <barzog at> on Wed, 20 Oct 2004 
> 08:08:32 -0500:
> EA> I've had really great performance with the em NICs, and bad experiences
> EA> with bge's (the hardware is flaky).
> OK, we'll try. Is there any problems with any of supported chipsets in 
> em-driver with polling? There many negative answer about polling support 
> in fxp on 82550, and good answers about 82558 and 82559 with fxp-driver.

Since you mentioned earlier that you run this on an SMP system, are you 
aware that device polling is available only for single CPU kernels, that 
is, not in SMP mode?  This is poorly documented, unfortunately.  You can 
find out about it by looking at the first couple of lines of 

Depending on what else you do on this server you might be better off 
with running it in single CPU mode, with device polling enabled (kernel 
compiled with DEVICE_POLLING and HZ=1000).  This could make a 
considerable difference with the fxp driver already.  I suggest to try 
it out before you start making changes to the hardware.

Uwe Doering         |  EscapeBox - Managed On-Demand UNIX Servers
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