Re: Interrupt time inflation on Xen

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Sun, Mar 20, 2016 at 08:19:23PM -0400, Thor Lancelot Simon wrote:
> 
> I've attached the dmesg from the GENERIC kernel and the boot-time
> messages (giving both the xen dmesg and NetBSD dmesg) from the XEN3_DOM0
> kernel.  Xen kernel is 4.5 from pkgsrc; it is NOT a debug kernel.
> 
> Interrupt routing seems to be the same, disk controller is on ioapic1 pin 6
> in both cases.

However, the Xen kernel emits:

ioapic1 at mainbus0 apid 7
ioapic1: can't remap to apid 7

Harmless?  What's particularly curious here to me is that we are seeing
twice as many interrupts as we should, in the poorly performing Xen
case.

Thor