From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: SLUB performance regression vs SLAB
Date: Thu, 04 Oct 2007 14:11:13 -0700 (PDT)
Message-ID: <20071004.141113.08322956.davem@davemloft.net>
References: <20071004192824.GA9852@linux.intel.com>
	<20071004.135537.39158051.davem@davemloft.net>
	<470554D9.2050505@redhat.com>
Mime-Version: 1.0
Content-Type: Text/Plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Cc: willy@linux.intel.com, clameter@sgi.com, nickpiggin@yahoo.com.au,
	hch@lst.de, mel@skynet.ie, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org, dgc@sgi.com, jens.axboe@oracle.com,
	suresh.b.siddha@intel.com
To: cebbert@redhat.com
Return-path: <linux-kernel-owner+glk-linux-kernel-3=40m.gmane.org-S1762122AbXJDVL2@vger.kernel.org>
In-Reply-To: <470554D9.2050505@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: linux-fsdevel.vger.kernel.org

From: Chuck Ebbert <cebbert@redhat.com>
Date: Thu, 04 Oct 2007 17:02:17 -0400

> How do you simulate reading 100TB of data spread across 3000 disks,
> selecting 10% of it using some criterion, then sorting and
> summarizing the result?

You repeatedly read zeros from a smaller disk into the same amount of
memory, and sort that as if it were real data instead.

You're not thinking outside of the box, and you need to do that to
write good test cases and fix kernel bugs effectively.