From owner-freebsd-current@FreeBSD.ORG Tue Jul 20 13:53:14 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 3A3EF16A4CE; Tue, 20 Jul 2004 13:53:14 +0000 (GMT) Received: from gundel.de.clara.net (gundel.de.clara.net [212.82.225.86]) by mx1.FreeBSD.org (Postfix) with ESMTP id EE09E43D41; Tue, 20 Jul 2004 13:53:13 +0000 (GMT) (envelope-from jesk@killall.org) Received: from port-212-202-54-113.dynamic.qsc.de ([212.202.54.113] helo=turbofresse) by gundel.de.clara.net with smtp (Exim 4.30; FreeBSD) id 1BmvCx-0008c4-QF; Tue, 20 Jul 2004 16:03:03 +0200 Message-ID: <044201c46e60$dfdb1810$45fea8c0@turbofresse> From: "jesk" To: "Robert Watson" , References: Date: Tue, 20 Jul 2004 15:53:02 +0200 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 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 13:53:14 -0000 > On Tue, 20 Jul 2004, Scott Long wrote: > > > 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. > > With Yarrow, /dev/random should just keep on chugging, so this is unlikely > to be the source. However, lots of /dev/random I/O may take a while to > yield if it's working hard in kernel, so if that is combined with a > scheduling nit of some sort, we could be looking at a starvation issue. > > Do we know if this is on a UP box or SMP box, and if so, whether it's > using HTT? I could try reproducing it here and see if I see the same > thing. > > Robert N M Watson FreeBSD Core Team, TrustedBSD Projects > robert@fledge.watson.org Principal Research Scientist, McAfee Research > > > > hi, i have tested it with /dev/zero, /dev/random and /dev/urandom, the same everywhere. as i mentioned i noticed the problem while mysqldump was dumping the mysqldatabase over night. in this timespan the mysqld didnt responsed to anything. after the dump(3minutes of time) the mysqld was back again and everything worked again. i have tested it with 2 UP boxes (i386/pIII) without HTT.