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To: Nai Xia <nai.xia@gmail.com>
Cc: dlaor@redhat.com, Andrea Arcangeli <aarcange@redhat.com>, Peter Zijlstra <a.p.zijlstra@chello.nl>, Ingo Molnar <mingo@kernel.org>, Hillf Danton <dhillf@gmail.com>, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Dan Smith <danms@us.ibm.com>, Linus Torvalds <torvalds@linux-foundation.org>, Andrew Morton <akpm@linux-foundation.org>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>, Paul Turner <pjt@google.com>, Suresh Siddha <suresh.b.siddha@intel.com>, Mike Galbraith <efault@gmx.de>, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>, Lai Jiangshan <laijs@cn.fujitsu.com>, Bharata B Rao <bharata.rao@gmail.com>, Lee Schermerhorn <Lee.Schermerhorn@hp.com>, Johannes Weiner <hannes@cmpxchg.org>, Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>, Christoph Lameter <cl@linux.com>, Alex Shi <alex.shi@intel.com>, Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, Don Morris <don.morris@hp.com>, Benjamin Herrenschmidt <benh@kernel.crashing.org>

On 06/30/2012 04:23 AM, Nai Xia wrote:

> Oh, sorry, I think I forgot few last comments in my last post:
>
> In case you really can take my advice and do comprehensive research,
> try to make sure that you compare the result of your fancy sampling algorithm
> with this simple logic:
>
>     "Blindly select a node and bind the process and move all pages to it."
>
> Stupid it may sound, I highly suspect it can approach the benchmarks
> you already did.
>
> If that's really the truth, then all the sampling and weighting stuff can
> be cut off.

All the sampling and weighing is there in order to deal with
processes that do not fit in one NUMA node.

This could be either a process that uses more memory than
what fits in one NUMA node, or a process with more threads
than there are processors in a NUMA node, or both.

That is what the complex code is for.

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