From owner-freebsd-current@FreeBSD.ORG Tue Jul 20 11:37:26 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9B2C416A4CE for ; Tue, 20 Jul 2004 11:37:26 +0000 (GMT) Received: from pooker.samsco.org (pooker.samsco.org [168.103.85.57]) by mx1.FreeBSD.org (Postfix) with ESMTP id DC37F43D53 for ; Tue, 20 Jul 2004 11:37:23 +0000 (GMT) (envelope-from scottl@samsco.org) Received: from [192.168.0.200] ([192.168.0.200]) (authenticated bits=0) by pooker.samsco.org (8.12.11/8.12.10) with ESMTP id i6KBhRKh058415; Tue, 20 Jul 2004 05:43:27 -0600 (MDT) (envelope-from scottl@samsco.org) Message-ID: <40FD03E7.8000300@samsco.org> Date: Tue, 20 Jul 2004 05:37:11 -0600 From: Scott Long User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.7) Gecko/20040702 X-Accept-Language: en-us, en MIME-Version: 1.0 To: jesk References: <028601c46e46$38fc9560$45fea8c0@turbofresse> In-Reply-To: <028601c46e46$38fc9560$45fea8c0@turbofresse> X-Enigmail-Version: 0.84.2.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, hits=0.0 required=3.8 tests=none autolearn=no version=2.63 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on pooker.samsco.org cc: freebsd-current@freebsd.org Subject: Re: I/O or Threading Suffer X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 20 Jul 2004 11:37:26 -0000 jesk wrote: > hello, > > i got problems with mysql under freebsd 5.2.1 and CURRENT. > > i got these problems on two machines with different hardware, but both are > single cpu machines. > used scheduler is ULE. > > problem description: > under high i/o load the mysqld isnt responding any more. > i tested this with dd if=/dev/urandom of=testfile bs=128k on the hdd an was > not > able to become any ouput from simple select-statements within a long period > of time > (above minutes). > i dont know if this problem occurs from mysql and its threads or if the i/o > subsystem has > any problems to deal fast enough with two intensives read and write > processes and its > priorities. > > best regards, > christian > If you are dd'ing from /dev/random, then you are depleting the entropy pool. Anything else that tries to get random numbers is going to block in strange ways. Trying just dd'ing from /dev/zero and see if that makes a difference. Scott