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Date: Tue, 16 Sep 2008 10:41:43 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Frank Mayhar <fmayhar@google.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
       Roland McGrath <roland@redhat.com>,
       Thomas Gleixner <tglx@linutronix.de>,
       Alexey Dobriyan <adobriyan@gmail.com>,
       Andrew Morton <akpm@linux-foundation.org>,
       Oleg Nesterov <oleg@tv-sign.ru>
Subject: Re: [PATCH 2.6.27-rc5 resubmit] Fix itimer/many thread hang.
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* Frank Mayhar <fmayhar@google.com> wrote:

> > the wider question is, shouldnt the UP case be just the same as the 
> > SMP case? Especially the type assymetry struct thread_group_cputime 
> > looks ugly. (and assymetries like that tend to be a constant source 
> > of breakage like the one below.)
> 
> I'm not overly fond of this one, either; I did it at Roland's 
> suggestion (it's all _his_ fault, yeah, _that's_ the ticket! :-); his 
> opinion IIRC was that the UP case will perform better without the 
> extra pointer dereferences.  I agree that it's a potential source of 
> pain such as the one you point out.

i dont know ... 

lets try that simplification as a delta patch, ok? Please check the 
before/after size of 'vmlinux' in a 'make defconfig' [with SMP disabled 
after make defconfig] UP build. If there's visible size difference then 
Roland's point holds.

	Ingo