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Date: Wed, 28 Aug 2002 19:16:31 +0200 (CEST)
From: Ingo Molnar <mingo@elte.hu>
Reply-To: Ingo Molnar <mingo@elte.hu>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: linux-kernel@vger.kernel.org, Linus Torvalds <torvalds@transmeta.com>
Subject: Re: [patch] "fully HT-aware scheduler" support, 2.5.31-BK-curr
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On Wed, 28 Aug 2002, Rusty Russell wrote:

> >  - HT-aware affinity.
> > 
> >    Tasks should attempt to 'stick' to physical CPUs, not logical CPUs.
> 
> Linus disagreed with this before when I discussed it with him, and with
> the current (stupid, non-portable, broken) set_affinity syscall he's
> right.

actually, affinity still works just fine, users can bind tasks to logical
CPUs as well. What i meant was the affinity logic of the scheduler (ie.  
affinity decisions done by the scheduler), not the externally visible
affinity API.

> You don't know if someone said "schedule me on cpu 0" because they
> really want to be scheduled on CPU 0, or because they really *don't*
> want to be scheduled on CPU 1 (where something else is running).  You
> can't just assume they are equivalent if they are the same physical CPU.

i dont assume that. There's also a fair amount of code in the kernel that
relies on binding threads to particular CPUs, the patch does not break
that in any way.

	Ingo

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