assigning interrupts

[John Baldwin]

On Friday 14 November 2008 03:23:06 am Ronnel P. Maglasang wrote:
> John Baldwin wrote:
> > On Thursday 13 November 2008 05:03:20 am Ronnel P. Maglasang wrote:
> >   
> >> Hi All,
> >>
> >> Is there a way to explicitly assign an interrupt
> >> of a device? I'm running on 6.3 and the two NICs
> >> share the same interrupt. Obviously this will affect
> >> the performance if the NICs are exposed to heavy network
> >> traffic.
> >>
> >> # vmstat -i
> >> interrupt                          total       rate
> >> <sniff>
> >> irq11: em0 vr0+                  1081099         77
> >> <sniff>
> >> Total                           16958562       1222
> >>
> >>
> >> Looking at the driver's code, I have the initial though
> >> that this is the place where I can modify.
> >>
> >> --
> >>         adapter->res_interrupt = bus_alloc_resource_any(dev,
> >>             SYS_RES_IRQ, &rid, RF_SHAREABLE | RF_ACTIVE);
> >> --
> >>
> >> I've tried changing RF_SHAREABLE to RF_ALLOCATED or other
> >> values but still could not get the desired result and worst
> >> the device fail to initialize. Is this possible in 6.3?
> >>     
> >
> > You can not easily assign them, no.  In many cases the interrupt pins from 
the 
> > devices may be hardwired to a single input pin on an interrupt controller.  
> > In that case there is nothing you can do.  You can read more about the 
gory 
> > details here:
> >
> > http://people.freebsd.org/~jhb/papers/bsdcan/2007/
> >
> >   
> What was changed in 7.x in terms of assigning interrupts? I have another
> box running on 7.0 (2 NICs). I noticed there are no devices sharing
> interrupts. But if 6.x is installed on the same box (previous installation),
> the two NICs will share the same interrupt. I'm now looking at the drivers.
> I assume this is not NIC-firmware related.

MSI.  Newer 6.x (6.4, possibly 6.3; if not by default on 6.3 then it can be 
enabled on 6.3 via 'hw.pci.enable_msi=1' tunable) will do it as well.

-- 
John Baldwin