Re: [patch] genapic: optimize & fix APIC mode setup

From: Ingo Molnar
Date: Mon Nov 13 2006 - 03:46:41 EST



* Siddha, Suresh B <suresh.b.siddha@xxxxxxxxx> wrote:

> There is an issue of using clustered mode along with cpu hotplug. More
> details are at the below link.
>
> http://marc.theaimsgroup.com/?l=linux-kernel&m=113261865814107&w=2

ok, to make sure i understand this right: it is not safe to switch any
local APIC in the system into clustered APIC mode on the E850x chipset
/at all/, because if one of the CPUs gets an INIT/startup IPI message
its local APIC will default to logical flat mode and might confuse the
chipset?

on large systems that have their APIC IDs set up to group CPUs amongst
different clusters and hence triggered cluster mode, the chipset does
not get confused by this, correct?

Ingo
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