Date: Sun, 11 Sep 2005 09:44:16 -0700 (PDT)
From: Zwane Mwaikambo <zwane@arm.linux.org.uk>
To: Ashok Raj <ashok.raj@intel.com>
cc: Andi Kleen <ak@muc.de>, Andrew Morton <akpm@osdl.org>,
       Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [patch 13/14] x86_64: Use common functions in cluster and physflat
 mode
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On Fri, 9 Sep 2005, Ashok Raj wrote:

> In general we need
> 
> flat_mode - #cpus <= 8 (Hotplug defined or not, so we use mask version 
>                        for safety)
> 
> physflat or cluster_mode when #cpus >8.

I agree there.

> If we choose physflat as default for #cpus <=8 (with hotplug) would make
> IPI performance worse, since it would do one cpu at a time, and requires 2 
> writes per cpu for each IPI v.s just 2 for a flat mode mask version of the API.

I don't see the benefit then :/ I certainly hope we don't go that route.

Thanks,
	Zwane

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