Subject: Re: IRQ handling difference between i386 and x86_64
From: Arjan van de Ven <arjan@infradead.org>
To: Krzysztof Oledzki <olel@ans.pl>
Cc: linux-kernel@vger.kernel.org
In-Reply-To: <Pine.LNX.4.64.0706301617240.16011@bizon.gios.gov.pl>
References: <Pine.LNX.4.64.0706301617240.16011@bizon.gios.gov.pl>
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Organization: Intel International BV
Date: Sat, 30 Jun 2007 08:40:35 -0700
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On Sat, 2007-06-30 at 16:55 +0200, Krzysztof Oledzki wrote:
> Hello,
> 
> It seems that IRQ handling is somehow different between i386 and x86_64.
> 
> In my Dell PowerEdge 1950 is it possible to enable interrupts spreading 
> over all CPUs. This a single CPU, four CORE system (Quad-Core E5335 Xeon) 
> so I think that interrupts migration may be useful. Unfortunately, it 
> works only with 32-bit kernel. Booting it with x86_64 leads to situation, 
> when all interrupts goes only to the first cpu matching a smp_affinity 
> mask.

arguably that is the most efficient behavior... round robin of
interrupts is the worst possible case in terms of performance

are you using irqbalance ? (www.irqbalance.org)


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