From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Chmielewski Subject: strange hdparm results with serverworks and pata-serverworks Date: Mon, 23 Feb 2009 21:37:21 +0100 Message-ID: <49A30901.1@wpkg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mx03.syneticon.net ([78.111.66.105]:46278 "EHLO mx03.syneticon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751066AbZBWUhG (ORCPT ); Mon, 23 Feb 2009 15:37:06 -0500 Received: from localhost (filter1.syneticon.net [192.168.113.83]) by mx03.syneticon.net (Postfix) with ESMTP id B5A3035E1C for ; Mon, 23 Feb 2009 21:37:03 +0100 (CET) Received: from mx03.syneticon.net ([192.168.113.84]) by localhost (mx03.syneticon.net [192.168.113.83]) (amavisd-new, port 10025) with ESMTP id 3ui8GG8KRZNu for ; Mon, 23 Feb 2009 21:37:01 +0100 (CET) Received: from [192.168.10.145] (koln-4db48cd5.pool.einsundeins.de [77.180.140.213]) by mx03.syneticon.net (Postfix) with ESMTPSA for ; Mon, 23 Feb 2009 21:37:01 +0100 (CET) Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: linux-ide@vger.kernel.org I have a ProLiant BL30p G1 machine running Debian Lenny (2.6.26 kernel). It also has two identical, 2.5 inch WDC WD2500BEVE-00WZT0 IDE drives (new drives, no smart/badblock errors). Both drives are connected to a single IDE channel this machine has. "hdparm -t" gives me different results for these drives: ~10 MB/s for hda, and ~20 MB/s for hdb with "serverworks" driver on Debian's 2.6.26 kernel. When using "pata-serverworks" with 2.6.28.7 kernel, hdparm shows the same results (~10 MB/s for sda, ~20 MB/s for sdb). However, when I run "dd if=/dev/sda of=/dev/null bs=64k", I can see with iostat that for the first 7-8 seconds, reads are with ~10 MB/s speed. Then, reads from sda are with ~20 MB/s or more and are on par with sdb. Similar dd test for sdb shows that it delivers with speed of ~20 MB/s from the first second. Is there an explanation for that? -- Tomasz Chmielewski http://wpkg.org