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Date: Sun, 16 Jan 2005 07:01:12 +0100
From: Lucky Green <shamrock@pakastelohi.cypherpunks.to>
To: freebsd-questions@freebsd.org
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Subject: DEVICE_POLLING vs. SMP kernels
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I am contemplating using the DEVICE_POLLING kernel option with an fxp NIC on FreeBSD 5.3 using an SMP kernel.

/usr/src/sys/kern/kern_poll.c clearly states that DEVICE_POLLING is incompatible with SNP kernels:

#ifdef SMP
#ifndef COMPILING_LINT
#error DEVICE_POLLING is not compatible with SMP
#endif
#endif

Yet there are various performance tuning FAQs floating around the Net stating that DEVICE_POLLING will work just 
fine with SMP kernels and that the user can safely delete the above section from kern_poll.c

This may well be the case, but if this is true, why wouldn't that section have been removed from kern_poll.c by 
now? What are the corner cases, if any, that an admin should be aware of that keep this error message in the 
code?

TIA,

-- Lucky Green <shamrock@cypherpunks.to> PGP encrypted email preferred.