Re: [PATCH v6] x86/apic: limit irq affinity

From: Arjan van de Ven <arjan@infradead.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Dimitri Sivanich <sivanich@sgi.com>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Ingo Molnar <mingo@elte.hu>,
	Suresh Siddha <suresh.b.siddha@intel.com>,
	Yinghai Lu <yinghai@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Jesse Barnes <jbarnes@virtuousgeek.org>,
	David Miller <davem@davemloft.net>,
	Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH v6] x86/apic: limit irq affinity
Date: Tue, 24 Nov 2009 06:50:22 -0800	[thread overview]
Message-ID: <20091124065022.6933be1a@infradead.org> (raw)
In-Reply-To: <alpine.LFD.2.00.0911241443110.24119@localhost.localdomain>

On Tue, 24 Nov 2009 14:55:15 +0100 (CET)
> > Furthermore, the /sysfs topology information should include IRQ
> > routing data in this case.
> 
> Hmm, not sure about that. You'd need to scan through all the nodes to
> find the set of CPUs where an irq can be routed to. I prefer to have
> the information exposed by the irq enumeration (which is currently in
> /proc/irq though).

yes please.

one device can have multiple irqs
one irq can be servicing multiple devices

expressing that in sysfs is a nightmare, while
sticking it in /proc/irq *where the rest of the info is* is
much nicer for apps like irqbalance

-- 
Arjan van de Ven 	Intel Open Source Technology Centre
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