Date: Thu, 9 Feb 2006 13:03:57 -0800
From: Ashok Raj <ashok.raj@intel.com>
To: Andrew Morton <akpm@osdl.org>
Cc: Ashok Raj <ashok.raj@intel.com>, ntl@pobox.com, dada1@cosmosbay.com,
       riel@redhat.com, linux-kernel@vger.kernel.org, torvalds@osdl.org,
       mingo@elte.hu, ak@muc.de, 76306.1226@compuserve.com, wli@holomorphy.com,
       heiko.carstens@de.ibm.com, pj@sgi.com
Subject: Re: [PATCH] percpu data: only iterate over possible CPUs
Message-ID: <20060209130356.A11732@unix-os.sc.intel.com>
References: <20060209160808.GL18730@localhost.localdomain> <20060209090321.A9380@unix-os.sc.intel.com> <20060209100429.03f0b1c3.akpm@osdl.org> <20060209105230.A10147@unix-os.sc.intel.com> <20060209123729.5fcd3808.akpm@osdl.org>
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In-Reply-To: <20060209123729.5fcd3808.akpm@osdl.org>; from akpm@osdl.org on Thu, Feb 09, 2006 at 12:37:29PM -0800
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On Thu, Feb 09, 2006 at 12:37:29PM -0800, Andrew Morton wrote:
> 
> There is no proposal to change cpu_present_map.
> 
> The problem is cpu_possible_map.  That is presently being initialised to
> CPU_MASK_ALL, which adversely affects perfoermance.  An NR_CPUS=16 kernel
> on a 2-way presently has cpu_possible_map=0xffff, which will hurt.

Think i miss typed earlier. What you proposed is the correct solution.

I will followup with similar change on ia64 as well, (currently we do this
in smp_build_cpu_map()). And add something similar to what we did for 
x86_64.
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