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RE: [Xen-devel] [PATCH] x86: change IO-APIC ack method default forsingle

To: 'Keir Fraser' <keir.fraser@xxxxxxxxxxxxx>, Jan Beulich <jbeulich@xxxxxxxxxx>
Subject: RE: [Xen-devel] [PATCH] x86: change IO-APIC ack method default forsingle IO-APIC systems
From: "Tian, Kevin" <kevin.tian@xxxxxxxxx>
Date: Thu, 22 Jan 2009 11:09:07 +0800
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Thread-topic: [Xen-devel] [PATCH] x86: change IO-APIC ack method default forsingle IO-APIC systems
>From: Keir Fraser
>Sent: Thursday, January 22, 2009 12:33 AM
>[...]
>and potentially nasty underlying issue. On the other hand, perhaps old
>ack_type is preferable (faster) if we can be sure we're on a 
>system where it
>is safe. Hmmm.
>

yes, it's faster and also better fit RT purpose with latency requirement. new
ack method has uncertain delay with dependency on guest ISR. But
one question here is, how to make sure whether system is safe? Is 
there automatic method to choose, or whitelist, or ask user to manually
change when seeing errors? :-(

Thanks,
Kevin

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