From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: xen 4 only seeing one keyboard and mouse Date: Tue, 24 Aug 2010 20:47:58 +0100 Message-ID: References: <20100824171019.GA18015@phenom.dumpdata.com> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20100824171019.GA18015@phenom.dumpdata.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Konrad Rzeszutek Wilk , M A Young Cc: "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org On 24/08/2010 18:10, "Konrad Rzeszutek Wilk" 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