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Re: [Xen-devel] Interrupts in Xen: Dynamic-irq and Phys-irq

To: John Que <qwejohn@xxxxxxxxx>
Subject: Re: [Xen-devel] Interrupts in Xen: Dynamic-irq and Phys-irq
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Mon, 18 Jul 2005 13:40:41 +0100
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On 18 Jul 2005, at 13:07, John Que wrote:

The "Dynamic-irq" also appears in Dom0 (for example, when you run
"cat /proc/interrupts" and look at the line containing "ctrl-if" or "console").

Besides it, In dom0 there is also "Phys-irq" ; for examples,after
running "cat /proc/interruupts" in line containing "eth0" or "ide0" or "ide1".

what is the difference between these 2 types of interrupts ?

Phys-irq's relate directly to hardware IRQ lines (e.g., eth0, your disc controller, etc). Dynamic-irq's are perhaps better described as 'virtual IRQs'. They have no direct relation to physical IRQ lines, but originate from things like timer events in Xen, or from the other half of a 'split' virtual block or network driver. We call them 'dynamic IRQs' because the IRQ numbers are dynamically allocated. :-)

 -- Keir

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