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From: Don Bowman <don@sandvine.com>
To: 'Avleen Vig' <lists-freebsd@silverwraith.com>,
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Date: Thu, 20 Nov 2003 12:58:58 -0500
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Subject: RE: Device polling, with SMP?
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From: Avleen Vig [mailto:lists-freebsd@silverwraith.com]
> 
> Has anyone here used DEVICE_POLLING on an SMP box?
> I have one server which does recieve ~130kpps at times on an 
> interface,
> but I cannot enable DEVICE_POLLING because hte system locks up under
> load from interrupts.
> 
> In this case I'm not sure which is better, disabling one of the CPU's,
> or trying to make DECIVE_POLLING work with SMP.
> 
> I read Luigi's paper at info.iet.unipi.it/~luigi/polling/ which at the
> end implies that DEVICE_POLLING on an SMP box might not make 
> sense - but
> right now for me it would make sense as both CPU's are locked:
>   One tries to handle interrupts
>   The other tries to manage the application
> 
> I could try forcing DEVICE_POLLING to compile as is suggested in that
> URL but I wanted to see if anyone had tried this before.
> 
> The interface is an FXP.

We use it on em. I just commented out the #error line that
says you can't do it.
device polling in idle doesn't work, and the user/system time
calculation isn't correct, but it works well otherwise.

--don