Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264418AbTKUT45 (ORCPT ); Fri, 21 Nov 2003 14:56:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264424AbTKUT45 (ORCPT ); Fri, 21 Nov 2003 14:56:57 -0500 Received: from mail.it.helsinki.fi ([128.214.205.39]:6374 "EHLO mail.it.helsinki.fi") by vger.kernel.org with ESMTP id S264422AbTKUT4x (ORCPT ); Fri, 21 Nov 2003 14:56:53 -0500 Date: Fri, 21 Nov 2003 21:56:42 +0200 (EET) From: Mikael Johansson X-X-Sender: mpjohans@soul.helsinki.fi To: Marcelo Tosatti cc: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: RAID-0 read perf. decrease after 2.4.20 In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1577 Lines: 43 Hello Marcelo and All! On Fri, 21 Nov 2003, Marcelo Tosatti wrote: > There have been no significant changes in the RAID driver in 2.4.21, so I > suspect the cause for the slowdowns might the changes to the IO scheduler > (ll_rw_blk.c) or VM changes. > > Isolating the -pre which the slowdown starts helps a lot. I tested a few kernels to pin point the where tha changes occured. It turned out that both 2.4.20 and 2.4.21-pre1 have bad read performance. The 2.4.20-ac's show good read speed. I tested it on two machines (different from yesterday). I also checked the VIA chipset drivers version; that's not the reason for the differences. Athlon XP 2400+, 2.09 GHz, 1.5 GB RAM, 2*160 GB Maxtor Maxtor 6Y080L0 VIA write read 2.4.19 none 10,000 9,000 K/sec (chipset not supported) 2.4.20 3.35 73,000 88,000 2.4.20-ac1 3.35-ac 70,000 135,000 2.4.20-ac2 3.35-ac 71,000 140,000 2.4.21-pre1 3.35-ac 71,000 79,000 2.4.21-pre3 3.35-ac 71,000 79,000 Athlon 1.4 GHz, 1.5 GB RAM, 2*80 GB IC35L040AVER07-0 (IBM, I think) 2.4.13-ac8 ? 49,000 44,000 K/sec 2.4.19 3.34 53,000 41,000 2.4.20-ac2 3.35-ac 50,000 69,000 2.4.21-pre1 3.35-ac 53,000 46,000 So there was apparently something very right with the 2.4.20-ac's. It would be nice to get it back :-) Have a nice weekend, Mikael J. http://www.helsinki.fi/~mpjohans/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/