From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 03 Oct 2005 08:25:28 -0700 From: "Martin J. Bligh" Reply-To: "Martin J. Bligh" Subject: Re: [PATCH 00/07][RFC] i386: NUMA emulation Message-ID: <86300000.1128353125@[10.10.2.4]> In-Reply-To: References: dlang@dlang.diginsite.com <83890000.1128352138@[10.10.2.4]> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: owner-linux-mm@kvack.org Return-Path: To: David Lang Cc: Magnus Damm , Dave Hansen , Magnus Damm , linux-mm , Linux Kernel Mailing List List-ID: --David Lang wrote (on Monday, October 03, 2005 08:13:09 -0700): > On Mon, 3 Oct 2005, Martin J. Bligh wrote: > >> --David Lang wrote (on Monday, October 03, 2005 08:03:44 -0700): >> >>> On Mon, 3 Oct 2005, Martin J. Bligh wrote: >>> >>>> But that's not the same at all! ;-) PAE memory is the same speed as >>>> the other stuff. You just have a 3rd level of pagetables for everything. >>>> One could (correctly) argue it made *all* memory slower, but it does so >>>> in a uniform fashion. >>> >>> is it? I've seen during the memory self-test at boot that machines slow down noticably as they pass the 4G mark. >> >> Not noticed that, and I can't see why it should be the case in general, >> though I suppose some machines might be odd. Got any numbers? > > just the fact that the system boot memory test takes 3-4 times as long with 8G or ram then with 4G of ram. I then boot a 64 bit kernel on the system and never use PAE mode again :-) > > if you can point me at a utility that will test the speed of the memory in different chunks I'll do some testing on the Opteron systems I have available. unfortunantly I don't have any Xeon systems to test this on. Mmm. 64-bit uniproc systems, with > 4GB of RAM, running a 32 bit kernel don't really strike me as a huge market segment ;-) M. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org