Messages in this thread | | | Date | Mon, 29 Mar 2010 06:16:49 -0700 | Subject | Re: 100%wa for long periods of time | From | Mark Knecht <> |
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On Sun, Mar 28, 2010 at 9:26 PM, andrew hendry <andrew.hendry@gmail.com> 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 <markknecht@gmail.com> 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. <SNIP>
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: [<ffffffff812dd063>] ? md_make_request+0xb6/0xf1 [<ffffffff8109c248>] ? sync_buffer+0x0/0x40 [<ffffffff8137a4fc>] ? io_schedule+0x2d/0x3a [<ffffffff8109c283>] ? sync_buffer+0x3b/0x40 [<ffffffff8137a879>] ? __wait_on_bit+0x41/0x70 [<ffffffff8109c248>] ? sync_buffer+0x0/0x40 [<ffffffff8137a913>] ? out_of_line_wait_on_bit+0x6b/0x77 [<ffffffff810438b2>] ? wake_bit_function+0x0/0x23 [<ffffffff8109c637>] ? sync_dirty_buffer+0x72/0xaa [<ffffffff81131b8e>] ? journal_commit_transaction+0xa74/0xde2 [<ffffffff8103abcc>] ? lock_timer_base+0x26/0x4b [<ffffffff81043884>] ? autoremove_wake_function+0x0/0x2e [<ffffffff81134804>] ? kjournald+0xe3/0x206 [<ffffffff81043884>] ? autoremove_wake_function+0x0/0x2e [<ffffffff81134721>] ? kjournald+0x0/0x206 [<ffffffff81043591>] ? kthread+0x8b/0x93 [<ffffffff8100bd3a>] ? child_rip+0xa/0x20 [<ffffffff81043506>] ? kthread+0x0/0x93 [<ffffffff8100bd30>] ? child_rip+0x0/0x20 livecd ~ #
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