From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755303Ab0I2T2d (ORCPT ); Wed, 29 Sep 2010 15:28:33 -0400 Received: from relay2.sgi.com ([192.48.179.30]:46165 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752411Ab0I2T2c (ORCPT ); Wed, 29 Sep 2010 15:28:32 -0400 Date: Wed, 29 Sep 2010 14:28:30 -0500 From: Robin Holt To: Nathan Fontenot Cc: Robin Holt , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@ozlabs.org, Greg KH , Dave Hansen , KAMEZAWA Hiroyuki Subject: Re: [PATCH 0/8] v2 De-Couple sysfs memory directories from memory sections Message-ID: <20100929192830.GK14068@sgi.com> References: <4CA0EBEB.1030204@austin.ibm.com> <20100928123848.GH14068@sgi.com> <4CA2313D.2030508@austin.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4CA2313D.2030508@austin.ibm.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 28, 2010 at 01:17:33PM -0500, Nathan Fontenot wrote: > On 09/28/2010 07:38 AM, Robin Holt wrote: > > I was tasked with looking at a slowdown in similar sized SGI machines > > booting x86_64. Jack Steiner had already looked into the memory_dev_init. > > I was looking at link_mem_sections(). > > > > I made a dramatic improvement on a 16TB machine in that function by > > merely caching the most recent memory section and checking to see if > > the next memory section happens to be the subsequent in the linked list > > of kobjects. > > > > That simple cache reduced the time for link_mem_sections from 1 hour 27 > > minutes down to 46 seconds. > > Nice! > > > > > I would like to propose we implement something along those lines also, > > but I am currently swamped. I can probably get you a patch tomorrow > > afternoon that applies at the end of this set. > > Should this be done as a separate patch? This patch set concentrates on > updates to the memory code with the node updates only being done due to the > memory changes. > > I think its a good idea to do the caching and have no problem adding on to > this patchset if no one else has any objections. I am sorry. I had meant to include you on the Cc: list. I just posted a set of patches (3 small patches) which implement the cache most recent bit I aluded to above. Search for a subject of "Speed up link_mem_sections during boot" and you will find them. I did add you to the Cc: list for the next time I end up sending the set. My next task is to implement a x86_64 SGI UV specific chunk of code to memory_block_size_bytes(). Would you consider adding that to your patch set? I expect to have that either later today or early tomorrow. Robin