This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


Re: [Xen-devel] xen 4 only seeing one keyboard and mouse

To: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>, M A Young <m.a.young@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] xen 4 only seeing one keyboard and mouse
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Tue, 24 Aug 2010 20:47:58 +0100
Cc: "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Tue, 24 Aug 2010 12:48:44 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <20100824171019.GA18015@xxxxxxxxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: ActDr1wq5AWLQfImQmmRK01qauMFdQAFeRVY
Thread-topic: [Xen-devel] xen 4 only seeing one keyboard and mouse
User-agent: Microsoft-Entourage/
On 24/08/2010 18:10, "Konrad Rzeszutek Wilk" <konrad.wilk@xxxxxxxxxx> wrote:

>> though the mouse and keyboard still don't work.
> I spoke with Keir a bit and he mentioned that there was a major
> rework of the IRQs in 4.0, wherein we would store the IRQs per CPU
> structure. That is instead of having a "globally" accessible irq structure
> wherein CPUs might contend for it.

Specifically the feature is "per-CPU IDTs". This increases the system-wide
IRQ limit from ~200 to ~200*nr_cpus. However, there is an increase in
complexity in that the interrupt vector assigned to an IRQ is CPU-local, and
must be re-allocated when an IRQ's target is moved between CPUs.

The main patch is c/s 20073 by Xiantao Zhang. It is the single biggest IRQ
restructuring patch in Xen 4.0 campared with 3.4.

 -- Keir

> The folks at Intel did this so they might
> have a better idea - and I can dig up from the hg annotate logs who they
> are and we can ask them. But before we go that route, the other idea was
> try to disable the irq balance code. Try passing in 'noirqbalance' and see
> what happens

Xen-devel mailing list

<Prev in Thread] Current Thread [Next in Thread>