From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263053AbTDFTMA (for ); Sun, 6 Apr 2003 15:12:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263055AbTDFTMA (for ); Sun, 6 Apr 2003 15:12:00 -0400 Received: from siaag1ad.compuserve.com ([149.174.40.6]:57984 "EHLO siaag1ad.compuserve.com") by vger.kernel.org with ESMTP id S263053AbTDFTL7 (for ); Sun, 6 Apr 2003 15:11:59 -0400 Date: Sun, 6 Apr 2003 15:21:00 -0400 From: Chuck Ebbert <76306.1226@compuserve.com> Subject: Re: hdparm -tT reports "suspicious results" ??? To: Mark Hahn Cc: linux-kernel Message-ID: <200304061523_MC3-1-3348-4760@compuserve.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Mark Hahn wrote: >does "PII ODP" mean a PII in an adapter that fits into a P6 socket? It is a factory Intel PII/333 with an HSF that fits in Socket 8. With its 512K full-speed cache it makes a PPro into a half-decent machine. Too bad they're so rare... >> /dev/hde: >> Timing buffer-cache reads: 128 MB in 2.62 seconds = 48.85 MB/sec > > hmm, slower dram and/or FSB. No, same exact machine in _every_ way, just a different kernel. It is slow ECC EDO memory, though. >> /dev/hde: >> Timing buffer-cache reads: 128 MB in 2.66 seconds = 48.14 MB/sec >> Timing buffered disk reads: 64 MB in 3.90 seconds = 16.41 MB/sec.> > > dram is still slow, but disk appears slower yet, so not obviously > contaminating the measurement. ..and that's 2.5 which measures much lower but doesn't seem to be that slow (still not tested, I'm testing RAID1 patches on 2.4 now.) > 53073H4, ecs k7s6a-pro, athlon/"1800", DDR: > /dev/hda: > Timing buffer-cache reads: 128 MB in 0.48 seconds =266.67 MB/sec > Timing buffered disk reads: 64 MB in 2.04 seconds = 31.37 MB/sec 3 x 33073H3, RAID1, Abit KT7A-RAID, Tbird 1333, PC133 SDRAM: Personalities : [raid0] [raid1] read_ahead 24 sectors md2 : active raid1 hdg9[0] hde8[2] hda8[1] 2409600 blocks [3/3] [UUU] 2.4.21-pre6: /dev/md2: Timing buffer-cache reads: 128 MB in 0.58 seconds =220.69 MB/sec Timing buffered disk reads: 64 MB in 2.71 seconds = 23.62 MB/sec 2.4.20aa1ce1(unreleased): /dev/md2: Timing buffer-cache reads: 128 MB in 0.59 seconds =216.95 MB/sec Timing buffered disk reads: 64 MB in 1.67 seconds = 38.32 MB/sec I have RAID1 patches that give 55% sequential IO improvements on K7 but they're not showing the same gains on the PPro (<20% so far.) Kernel, chipset, CPU and disk controller are all different, though I expected to get proportional gains on any hardware. AFAICT hdparm says "suspicious results" when the disk speed is greater than one-half the buffer speed. I just got 51.20 and 26.34 on the PPro with my patches and the message came out again. -- Chuck I am not a number!