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Date: Mon, 17 Apr 2006 07:31:53 -0700
From: "Martin J. Bligh" <mbligh@mbligh.org>
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To: "Robert M. Stockmann" <stock@stokkie.net>
Cc: linux-kernel@vger.kernel.org, Randy Dunlap <rddunlap@osdl.org>,
       Linus Torvalds <torvalds@osdl.org>, Andrew Morton <akpm@osdl.org>,
       Andre Hedrick <andre@linux-ide.org>,
       Manfred Spraul <manfreds@colorfullife.com>, Alan Cox <alan@redhat.com>,
       Kamal Deen <kamal@kdeen.net>
Subject: Re: irqbalance mandatory on SMP kernels?
References: <Pine.LNX.4.44.0604171438490.14894-100000@hubble.stokkie.net>
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Robert M. Stockmann wrote:
> Hi,
> 
> I noticed that the latest editions of RedHat EL 4.3 and direct
> descendants today need a program called irqbalance to activate
> true SMP IRQ load balancing for your machine's hardware.
> 
> If one boots a SMP kernel (2.4.xx or 2.6.xx) kernel on a machine
> which either has 2 or more physical CPU's (also dual-core CPU's) 
> , and one does not start up the irqbalance util from the
> kernel-utils package ( see e.g. 

There is an in-kernel IRQ balancer. Redhat just choose to turn it
off, and do it in userspace instead. You can re-enable it if you
compile your own kernel.

M.