From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752094Ab0C2NQw (ORCPT ); Mon, 29 Mar 2010 09:16:52 -0400 Received: from mail-pv0-f174.google.com ([74.125.83.174]:46219 "EHLO mail-pv0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752011Ab0C2NQu convert rfc822-to-8bit (ORCPT ); Mon, 29 Mar 2010 09:16:50 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=bPOm5QeweK3Sy2IRxYEOE60u7rI4XAhRvF3b2HsbDmE0mb35IJWoqIQd4M5EL7rcEM wolRJfeWu98sCWQdBkrArSGXB8uuKjeNxXsY6vcHju4Ebhx+odzryASKmfJlPSrJWroU 8iSXYCCsV0aZrHuuDRe+XRTW/0x4/gsiQAhmA= MIME-Version: 1.0 In-Reply-To: References: <5bdc1c8b1003282044s23347905mfca7c41c37db6f18@mail.gmail.com> Date: Mon, 29 Mar 2010 06:16:49 -0700 Message-ID: <5bdc1c8b1003290616x75aacecdieb01898a8f9160be@mail.gmail.com> Subject: Re: 100%wa for long periods of time From: Mark Knecht To: andrew hendry Cc: Linux Kernel List Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Mar 28, 2010 at 9:26 PM, andrew hendry wrote: > Hi, > > Do you know what is causing the wait? > Probably not the best way, but I have used something like the > following for a similar case before: > echo "1" > /proc/sys/vm/block_dump > ... wait a short while ... > echo "0" > /proc/sys/vm/block_dump > Then have a look at dmesg | egrep "READ|WRITE|dirtied" > > Andrew. > > On Mon, Mar 29, 2010 at 2:44 PM, Mark Knecht wrote: >> Hi all, >>   Long time lurker. Seldom post here. I'm not a programmer. >> >>   OK, so I'm bring up new hardware - Intel i7 920, Intel DX58SO >> motherboard, 6GB Crucial triple channel DRAM. Using both the Gentoo >> install CD (2.6.32 based) as well as 2.6.33-gentoo after booting the >> install I am running into long periods of time - sometimes 30 seconds, >> sometimes lasting minutes, where the machine appears to hang or slow >> down very drastically. The only thing I've noticed so far is that >> there are 100% waiting periods showing up in top. No messages in dmesg >> or /var/log/messages. Just long periods where the the compiler acts >> like the system has really slowed down and sometimes appears almost >> completely dead. >> >>   When this clears up then the system screams along building >> software. When it happens is see things like the following where CPU's >> 1 & 5 sit at 100% waiting which lasted 2 or 3 minutes before clearing >> up. The CPU that goes to 100% does move around but it does seem to >> land on #5 more than others. OK, that catches some info. Here I was doing an emerge --sync and went to 100% for a little while flush-8:0(3365): WRITE block 33555792 on sda3 flush-8:0(3365): WRITE block 33555800 on sda3 flush-8:0(3365): WRITE block 33701984 on sda3 flush-8:0(3365): WRITE block 33720128 on sda3 flush-8:0(3365): WRITE block 33721496 on sda3 flush-8:0(3365): WRITE block 33816576 on sda3 flush-8:0(3365): WRITE block 33816584 on sda3 flush-8:0(3365): WRITE block 33816592 on sda3 flush-8:0(3365): WRITE block 33817664 on sda3 flush-8:0(3365): WRITE block 33817672 on sda3 flush-8:0(3365): WRITE block 33817680 on sda3 flush-8:0(3365): WRITE block 33817688 on sda3 flush-8:0(3365): WRITE block 33817696 on sda3 flush-8:0(3365): WRITE block 33817728 on sda3 keeper ~ # When I first started building this machine 2 days ago I wanted to set up RAID. I was using the Gentoo install CD at the time. In the process of loading software I caught a couple error messages so I backed away from RAID at the time. However since those messages report things being 'blocked' for more than 120 second it's probably related. Again, this hasn't happened since I disable RAID, but I do want to go back to RAID as this is a low-end home file server. File system type is ext3 if it matters. INFO: task kjournald:17466 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kjournald D ffff8800280bbe00 0 17466 2 0x00000000 ffff8801adf9d890 0000000000000046 0000000000000000 0000000000000000 ffff8801adcbde44 0000000000004000 000000000000fe00 000000000000c878 0000000800000050 ffff88017a99aa40 ffff8801af90a150 ffff8801adf9db08 Call Trace: [] ? md_make_request+0xb6/0xf1 [] ? sync_buffer+0x0/0x40 [] ? io_schedule+0x2d/0x3a [] ? sync_buffer+0x3b/0x40 [] ? __wait_on_bit+0x41/0x70 [] ? sync_buffer+0x0/0x40 [] ? out_of_line_wait_on_bit+0x6b/0x77 [] ? wake_bit_function+0x0/0x23 [] ? sync_dirty_buffer+0x72/0xaa [] ? journal_commit_transaction+0xa74/0xde2 [] ? lock_timer_base+0x26/0x4b [] ? autoremove_wake_function+0x0/0x2e [] ? kjournald+0xe3/0x206 [] ? autoremove_wake_function+0x0/0x2e [] ? kjournald+0x0/0x206 [] ? kthread+0x8b/0x93 [] ? child_rip+0xa/0x20 [] ? kthread+0x0/0x93 [] ? child_rip+0x0/0x20 livecd ~ # Thanks, Mark