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Date: Tue, 24 Mar 2015 22:14:06 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: cmetcalf@ezchip.com
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Frederic Weisbecker <fweisbec@gmail.com>
Subject: Re: [PATCH 1/4] tile: support arch_irq_work_raise
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References: <1427224895-30830-1-git-send-email-cmetcalf@ezchip.com>
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On Tue, Mar 24, 2015 at 03:21:32PM -0400, cmetcalf@ezchip.com wrote:
> From: Chris Metcalf <cmetcalf@ezchip.com>
> 
> Tile includes a hypervisor hook to deliver messages to arbitrary
> tiles, so we can use that to raise an interrupt as soon as
> possible on our own core.  Unfortunately the Tilera hypervisor
> disabled that support on principle in previous releases, but
> it will be available in MDE 4.3.4 and later.

Can you program a timer in the (recent) past which will instantly
trigger an interrupt? This is what PPC64 does to implement the self-ipi.