[Pkg-xen-devel] Bug#577788: dom0 kernels should suggest irqbalance

[Ben Hutchings]

On Sun, 2014-08-31 at 03:10 +0100, Ian Campbell wrote:
> (copying debian-kernel for reasons which will hopefully become obvious)
> 
> On Mon, 8 Jul 2013 18:10:58 +0200 =?UTF-8?Q?Moritz_M=C3=BChlenhoff?= <jmm at inutil.org> wrote:
> > In current Debian kernel there's no special Xen dom0 kernel image and depending
> > on irqbalance in the kernel package would be overkill.
> 
> Would it? I thought irqbalance is actually required even for native with
> modern kernels, since the kernel doesn't do any balancing by itself (any
> more, it did use to).

I don't know that it's generally required, but it can be useful if there
is a lot of work done in interrupt or softirq context (and have multiple
processors).

> Looking on my laptop for instance I see that all interrupts are going to
> CPU0 out of the 4 processes. On the other hand my workstation does seem
> to have balanced IRQs despite having no irqbalanced running, so I don't
> know.
> 
> I reckon the kernel probably should recommend irqbalance these days, but
> in any case there is no reason for Xen to do something different (since
> IRQ balancing should work as on native).

At least kernels that support SMP could recommend it.

Ben.

-- 
Ben Hutchings
Experience is directly proportional to the value of equipment destroyed.
                                                         - Carolyn Scheppner
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