# Does FreeBSD support interrupt binding in SMP systems?



## wenji (Mar 19, 2009)

Could anybody help me out, thanks in advance.

Linux support the interrupt affinity (interrupt binding) in SMP systems. For example, the NIC interrupt can be redirected by tweaking "/proc/irq/nic_irq_xxx/smp_affinity".

Does FreeBSD has similar features?

thanks,

wenji


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## trev (Mar 23, 2009)

I do not believe it does.


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## vermaden (Mar 23, 2009)

wenji said:
			
		

> Linux support the interrupt affinity (interrupt binding) in SMP systems. For example, the NIC interrupt can be redirected by tweaking "/proc/irq/nic_irq_xxx/smp_affinity".
> 
> Does FreeBSD has similar features?



FreeBSD 8 Supports both CPU and IRQ setting:
http://ivoras.sharanet.org/freebsd/freebsd8.html



> User-controllable CPU/IRQ binding (jhb)
> User-controllable CPU-thread binding with support for CPU sets (jeffr)


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## trev (Mar 23, 2009)

vermaden said:
			
		

> FreeBSD 8 Supports both CPU and IRQ setting:
> http://ivoras.sharanet.org/freebsd/freebsd8.html



Really? I thought it was still in the "intended" basket and hadn't yet been realised?


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## rwatson@ (May 16, 2009)

trev said:
			
		

> Really? I thought it was still in the "intended" basket and hadn't yet been realised?



To follow up to an old thread: yes, this is implemented. You can use cpuset(8)'s '-x' to direct low-level interrupts to a specific CPU, if supported by the underlying hardware.


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