[illumos-Developer] Available MSI(-x) interrupt limit.

[Garrett D'Amore]

Right, its the APIC.  Newer systems use the APIX which is much more flexible.  These are typically used with MSI-X.  MSI-X also uses a more flexible interrupt routing scheme, so its possible to route different interrupts to different cpus more easily.

I've not seen many MSI devices.  I've seen a lot of MSI-X though.

  -- Garrett D'Amore

On Jun 7, 2011, at 10:02 PM, "Alexey Zaytsev" <alexey.zaytsev at gmail.com> wrote:

> On Tue, Jun 7, 2011 at 21:53, Garrett D'Amore <garrett at nexenta.com> wrote:
>> You misunderstand.  The default is 2 now.  If you want more, it take extraordinary measures.
>> 
>> On illumos there is a more modern API that allows "cooperative" device drivers to get more, with a promise that they will yield the resources if other devices need them later.
> 
> By the way, what's the limit of MSI interrupts in a typical x86
> system? And where does it come from? From my understanding, it must
> come from the APIC, but I might be wrong.