From owner-freebsd-questions@FreeBSD.ORG Thu Nov 23 03:49:19 2006 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id BE58D16A47B for ; Thu, 23 Nov 2006 03:49:19 +0000 (UTC) (envelope-from freebsd@sopwith.solgatos.com) Received: from schitzo.solgatos.com (pool-71-117-237-189.ptldor.fios.verizon.net [71.117.237.189]) by mx1.FreeBSD.org (Postfix) with ESMTP id 05AAC43D45 for ; Thu, 23 Nov 2006 03:48:44 +0000 (GMT) (envelope-from freebsd@sopwith.solgatos.com) Received: from schitzo.solgatos.com (localhost.home.localnet [127.0.0.1]) by schitzo.solgatos.com (8.13.8/8.13.6) with ESMTP id kAN3nGDK013652 for ; Wed, 22 Nov 2006 19:49:16 -0800 Received: from sopwith.solgatos.com (uucp@localhost) by schitzo.solgatos.com (8.13.8/8.13.4/Submit) with UUCP id kAN3nGZP013649 for freebsd-questions@freebsd.org; Wed, 22 Nov 2006 19:49:16 -0800 Received: from localhost by sopwith.solgatos.com (8.8.8/6.24) id DAA04594; Thu, 23 Nov 2006 03:41:46 GMT Message-Id: <200611230341.DAA04594@sopwith.solgatos.com> To: freebsd-questions@freebsd.org In-reply-to: Your message of "Wed, 22 Nov 2006 21:37:33 EST." <20061123023733.GA46545@xor.obsecurity.org> Date: Wed, 22 Nov 2006 19:41:46 +0000 From: Dieter Subject: Re: processes not getting fair share of available disk I/O (was: Re: TCP parameters and interpreting tcpdump output ) X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 23 Nov 2006 03:49:19 -0000 > > > > > > time ls on a small directory on disk2 > > > > > >=3D3D20 > > > > > > real 4m51.911s > > > > > > user 0m0.000s > > > > > > sys 0m0.002s > > > > > >=3D3D20 > > > > > > I expect access to a busy disk to take longer, but 5 minutes is > > > > > > a bit much. And that's the root directory of the filesystem, > > > > > > it didn't have to follow a long chain of directories to get there. > > > > > >=3D3D20 > > > > > > Sometimes I see long delays when accessing disk3, but it is > > > > > > behaving at the moment. > > > > >=3D20 > > > > > ls still has to acquire a number of locks in order to be sure that = > the > > > > > contents of the directory aren't changing. If there are lots of ot= > her > > > > > processes all competing for these locks, it will be slow. It looks > > > > > like that's the case on your system, although details of your workl= > oad > > > > > have been trimmed from your email. > > > >=3D20 > > > > In telnet window 1: > > > >=3D20 > > > > cd /disk1/ > > > > cp -ip very_big_file /disk2/bar/ (the workload) > > > >=3D20 > > > > In telnet window 2: > > > >=3D20 > > > > time ls /disk3/foo1/ (make sure time and ls are cached in memory) > > > > time ls /disk3/foo2/ (see timing numbers above) > > > > time ls /disk2/ (see timing numbers above) > > > >=3D20 > > > > The /disk2/ directory is small, only contains 3 directories and .snap > > > >=3D20 > > > > Would the cp into /disk2/bar/ lock the /disk2/ directory? > > >=20 > > > It shouldn't do. > > >=20 > > > What scheduler are you using? > >=20 > > kern.sched.name: 4BSD > > kern.sched.quantum: 100000 > > kern.sched.preemption: 1 > > OK, that's correct. Can you also provide details of your disk > hardware (e.g. dmesg) and kernel configuration? FreeBSD 6.0 Kernel is stock except for addition of: device atapicam # needed to burn dvd /boot/loader.conf: console="comconsole" hw.ata.wc=0 hw.ata.atapi_dma="1" kern.ipc.nmbclusters="256000" Mainboard: Tyan Tomcat k8e 2865 CPU: AMD64 3000+ Chipset: Nvidia nforce4 ultra Memory: 2 GB DDR400 ECC Disks: 4x Seagate 7200 rpm SATA 1x Seagate 7200 rpm PATA 1x LG CD/DVD atapci0: port 0x1f0-0x1f7,0x3f6,0x170-0x177,0x376,0xe000-0xe00f at device 6.0 on pci0 ata0: on atapci0 ata1: on atapci0 atapci1: port 0x9f0-0x9f7,0xbf0-0xbf3,0x970-0x977,0xb70-0xb73,0xcc00-0xcc0f mem 0xfebfb000-0xfebfbfff irq 10 at device 7.0 on pci0 ata2: on atapci1 ata3: on atapci1 atapci2: port 0x9e0-0x9e7,0xbe0-0xbe3,0x960-0x967,0xb60-0xb63,0xb800-0xb80f mem 0xfebfa000-0xfebfafff irq 11 at device 8.0 on pci0 ata4: on atapci2 ata5: on atapci2 acd0: DVDR at ata0-master UDMA66 ad2: 305245MB at ata1-master UDMA100 ad4: 238475MB at ata2-master SATA150 ad6: 238475MB at ata3-master SATA150 ad8: 238475MB at ata4-master SATA150 ad10: 305245MB at ata5-master SATA150 cd0 at ata0 bus 0 target 0 lun 0