Re: Is there a way to change irq numbers of pcie cards ?

[Bjorn Helgaas <bjorn.helgaas@hp.com>]

[I added linux-pci, where more PCI-savvy people will see it.]

On Wednesday, June 02, 2010 06:08:33 am Bert dd wrote:
> Hi,
> Is there a way to change irq numbers of pcie cards ?
> 
> I have a supermicro machine with 2 raid cards (lsi 9260-8i and lsi 9260-8e) and
> one nvidia GTX480 graphics card.
> The problem is that all these pcie cards are assigned the same irq number,
> and thus all the interrupts are routed to the same cpu which can not
> handle this.
> If I replace the nvidia GTX480 with an older graphics card(too old for
> our purposes (GTX295)), the graphics card gets a different irq number
> than the raid cards, the interrups of the graphics card are handled by
> a different cpu than those of the raid cards, and the read/write speed
> of the raid increases.
> I am reading/writing at 2.5 GB/s to the raid and I am uploading
> textures at 0.5 GB/s to the graphics hardware.
> Is there a way to change the irq numbers of the pcie cards ?
> I am using IOAPIC for interrupt routing.

I would think performance-oriented PCIe devices would be using
some sort of MSI, but I'm not really an expert in that area.

Can you post your /proc/interrupts and complete dmesg log in
case nobody jumps in with an obvious answer?

Bjorn

> I am using ubuntu - kernel version 2.6.31-14-generic.
> 
> thanks,
>   Bert De Decker
>   bert.dedecker@uhasselt.be