Message-ID: <1338971020.2749.64.camel@twins>
Subject: RE: [PATCH 0/6] x86/cpu hotplug: Wake up offline CPU via mwait or
 nmi
From: Peter Zijlstra <peterz@infradead.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: "Luck, Tony" <tony.luck@intel.com>, "Yu, Fenghua" <fenghua.yu@intel.com>,
        Rusty Russell <rusty@rustcorp.com.au>, Ingo Molnar <mingo@elte.hu>,
        H Peter Anvin <hpa@zytor.com>,
        "Siddha, Suresh B" <suresh.b.siddha@intel.com>,
        "Mallick, Asit K" <asit.k.mallick@intel.com>,
        Arjan Dan De Ven <arjan@linux.intel.com>,
        linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>,
        linux-pm <linux-pm@vger.kernel.org>,
        "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Date: Wed, 06 Jun 2012 10:23:40 +0200
In-Reply-To: <alpine.LFD.2.02.1206052337300.3086@ionos>
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On Wed, 2012-06-06 at 00:09 +0200, Thomas Gleixner wrote:
> > Well, no not like that, but I think we could do with some coupling
> > there. Like steer active interrupts away when they keep hitting idle
> > state.
> 
> That's possible, but that wants a well coordinated mechanism which
> takes the user space steering into account.

Sure, if the provided interrupt affinity mask doesn't allow this, we
loose. But typically those are all bits set.

> I'm not saying it's impossible, I'm just trying to imagine the extra
> user space interfaces needed for that. 

None, preferably.
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