Message-ID: <47A8C508.6010305@cs.helsinki.fi>
Date: Tue, 05 Feb 2008 22:20:24 +0200
From: Pekka Enberg <penberg@cs.helsinki.fi>
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To: Christoph Lameter <clameter@sgi.com>
CC: linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: SLUB: Support for statistics to help analyze allocator behavior
References: <Pine.LNX.4.64.0802042217460.6801@schroedinger.engr.sgi.com> <Pine.LNX.4.64.0802050923220.14675@sbz-30.cs.Helsinki.FI> <Pine.LNX.4.64.0802051005010.11705@schroedinger.engr.sgi.com>
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Christoph Lameter wrote:
> On Tue, 5 Feb 2008, Pekka J Enberg wrote:
> 
>> Hi Christoph,
>>
>> On Mon, 4 Feb 2008, Christoph Lameter wrote:
>>> The statistics provided here allow the monitoring of allocator behavior
>>> at the cost of some (minimal) loss of performance. Counters are placed in
>>> SLUB's per cpu data structure that is already written to by other code.
>> Looks good but I am wondering if we want to make the statistics per-CPU so 
>> that we can see the kmalloc/kfree ping-pong of, for example, hackbench 
> 
> We could do that.... Any idea how to display that kind of information 
> in a meaningful way. Parameter conventions for slabinfo?

We could just print out one total summary and one summary for each CPU 
(and maybe show % of total allocations/fees. That way you can 
immediately spot if some CPUs are doing more allocations/freeing than 
others.

			Pekka
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