From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751180AbWFSGxr (ORCPT ); Mon, 19 Jun 2006 02:53:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751211AbWFSGxr (ORCPT ); Mon, 19 Jun 2006 02:53:47 -0400 Received: from embla.aitel.hist.no ([158.38.50.22]:8633 "HELO embla.aitel.hist.no") by vger.kernel.org with SMTP id S1751180AbWFSGxr (ORCPT ); Mon, 19 Jun 2006 02:53:47 -0400 Message-ID: <4496492A.1030907@aitel.hist.no> Date: Mon, 19 Jun 2006 08:50:18 +0200 From: Helge Hafting User-Agent: Thunderbird 1.5.0.2 (X11/20060516) MIME-Version: 1.0 To: Jeff Gold CC: Mark Lord , linux-kernel@vger.kernel.org Subject: Re: Serial Console and Slow SCSI Disk Access? References: <448DDC7F.4030308@mazunetworks.com> <448DDF1D.5020108@rtr.ca> <448DE4F1.9000407@mazunetworks.com> In-Reply-To: <448DE4F1.9000407@mazunetworks.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Jeff Gold wrote: > Mark Lord wrote: >> This can happen if there are kernel messages being printed on the >> serial console. >> If all is quiet, I would expect things to be as fast as normal >> elsewhere. > > Thank you for the suggestion. I don't see much in /var/log/messages > (syslogd is running). There are 3326 lines taking up about 256 kB > there, and when I run hdparm runs no further messages are generated. > > I don't have anything attached to the serial port at the moment. > Could that cause problems? I'm going to attach something and see what > happens. Other advice is still welcome. With nothing attached, any write to the serial device might go through a lengthy timeout because of flow control. I'd consider that a bug in this case though, and there is usually no console printout per scsi disk access either. I would not be surprised if your serial console causes a longer boot time, as all boot messages have to be transferred over the slow serial link or in the worst case timed out one message at a time. But I can't see why it'd make scsi disks slower. The scsi host adapter initialization writes some messages of course, but there should be no more console accesses during a hdparm test run. Helge Hafting