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Date: Fri, 2 Mar 2007 20:19:26 -0800
From: William Lee Irwin III <wli@holomorphy.com>
To: Christoph Lameter <clameter@engr.sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, Rik van Riel <riel@redhat.com>,
       Bill Irwin <bill.irwin@oracle.com>, Mel Gorman <mel@skynet.ie>,
       npiggin@suse.de, mingo@elte.hu, jschopp@austin.ibm.com,
       arjan@infradead.org, torvalds@linux-foundation.org, mbligh@mbligh.org,
       linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: The performance and behaviour of the anti-fragmentation related patches
Message-ID: <20070303041926.GE23573@holomorphy.com>
References: <20070302100619.cec06d6a.akpm@linux-foundation.org> <Pine.LNX.4.64.0703021012170.17676@schroedinger.engr.sgi.com> <45E86BA0.50508@redhat.com> <20070302211207.GJ10643@holomorphy.com> <45E894D7.2040309@redhat.com> <20070302135243.ada51084.akpm@linux-foundation.org> <45E89F1E.8020803@redhat.com> <20070302142256.0127f5ac.akpm@linux-foundation.org> <20070303003319.GB23573@holomorphy.com> <Pine.LNX.4.64.0703021913030.31787@schroedinger.engr.sgi.com>
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On Fri, 2 Mar 2007, William Lee Irwin III wrote:
>> AIUI that phenomenon is universal to NUMA. Maybe it's time we
>> reexamined our locking algorithms in the light of fairness
>> considerations.

On Fri, Mar 02, 2007 at 07:15:38PM -0800, Christoph Lameter wrote:
> This is a phenomenon that is usually addressed at the cache logic level. 
> Its a hardware maturation issue. A certain package should not be allowed
> to hold onto a cacheline forever and other packages must have a mininum 
> time when they can operate on that cacheline.

I think when I last asked about that I was told "cache directories are
too expensive" or something on that order, if I'm not botching this,
too. In any event, the above shows a gross inaccuracy in my statement.


-- wli