ubuntu – Adams Bros Blog http://blog.adamsbros.org Sun, 16 Nov 2014 03:59:00 +0000 en-US hourly 1 https://wordpress.org/?v=5.2.2 Ubuntu Sluggish or Slow http://blog.adamsbros.org/2011/07/21/ubuntu-sluggish-or-slow/ http://blog.adamsbros.org/2011/07/21/ubuntu-sluggish-or-slow/#comments Fri, 22 Jul 2011 00:44:46 +0000 http://blog.adamsbros.org/?p=400 I was recently having a problem where my new computer was becoming extremely sluggish while running Ubuntu Linux 11.04.  The keyboard input was very delayed and slow.  The graphics were terribly slow.  Just about everything in the system became very slow.  I’ve heard reports from similar problems, of complete lockups.  It seemed to be linked to when the screensaver was activated, or power management was activated.  But, after having disabled both, and continuing to have problems, I realized that wasn’t it.  Keep reading for the solution to my problem; I hope it helps you too.

I searched Google to no avail.  I was completely unable to use the correct search terms to find anything relevant, except to find that others were having the same problems.  But, I found no solutions in any of the posts I found, or even hints of how to diagnose such a thing.  So, I finally decided that I should be a programmer instead of a user.  After all, I moved to Ubuntu so that I could be a user; I don’t really have the time to be tinkering with my system these days.

My new system is made up of the following core components

  • ASUS P8P67 EVO motherboard
  • I7 2600k
  • eVGA GeForce GTX 460 video card

So, after having put on my programmers cap, I decided to go fishing.  Obviously the first place I looked was /var/log/syslog.  In there, I found the following…

Jul 20 21:56:39 tda-desktop kernel: [ 9607.079961] eth0: no IPv6 routers present
Jul 20 21:57:06 tda-desktop kernel: [ 9633.800384] irq 16: nobody cared (try booting with the "irqpoll" option)
Jul 20 21:57:06 tda-desktop kernel: [ 9633.800386] Pid: 0, comm: swapper Tainted: P            2.6.38-10-generic #46-Ubuntu
Jul 20 21:57:06 tda-desktop kernel: [ 9633.800387] Call Trace:
Jul 20 21:57:06 tda-desktop kernel: [ 9633.800389]    [] ? __report_bad_irq.clone.2+0x2b/0xa0
Jul 20 21:57:06 tda-desktop kernel: [ 9633.800395]  [] ? note_interrupt+0x19a/0x1e0
Jul 20 21:57:06 tda-desktop kernel: [ 9633.800396]  [] ? handle_fasteoi_irq+0xdd/0x110
Jul 20 21:57:06 tda-desktop kernel: [ 9633.800399]  [] ? handle_irq+0x22/0x40
Jul 20 21:57:06 tda-desktop kernel: [ 9633.800402]  [] ? do_IRQ+0x5d/0xe0
Jul 20 21:57:06 tda-desktop kernel: [ 9633.800404]  [] ? ret_from_intr+0x0/0x15
Jul 20 21:57:06 tda-desktop kernel: [ 9633.800405]    [] ? intel_idle+0xca/0x120
Jul 20 21:57:06 tda-desktop kernel: [ 9633.800409]  [] ? intel_idle+0xa9/0x120
Jul 20 21:57:06 tda-desktop kernel: [ 9633.800411]  [] ? cpuidle_idle_call+0xaa/0x1b0
Jul 20 21:57:06 tda-desktop kernel: [ 9633.800414]  [] ? cpu_idle+0xa6/0xf0
Jul 20 21:57:06 tda-desktop kernel: [ 9633.800416]  [] ? rest_init+0x75/0x80
Jul 20 21:57:06 tda-desktop kernel: [ 9633.800418]  [] ? start_kernel+0x3f5/0x400
Jul 20 21:57:06 tda-desktop kernel: [ 9633.800421]  [] ? x86_64_start_reservations+0x132/0x136
Jul 20 21:57:06 tda-desktop kernel: [ 9633.800423]  [] ? x86_64_start_kernel+0xd1/0xe0
Jul 20 21:57:06 tda-desktop kernel: [ 9633.800424] handlers:
Jul 20 21:57:06 tda-desktop kernel: [ 9633.800425] [] (nv_kern_isr+0x0/0x80 [nvidia])
Jul 20 21:57:06 tda-desktop kernel: [ 9633.800526] [] (rtl8169_interrupt+0x0/0x250 [r8169])
Jul 20 21:57:06 tda-desktop kernel: [ 9633.800529] Disabling IRQ #16

As you can see, two drivers are in use on IRQ 16; the nvidia and rtl8169 drivers. I ended up doing some more analysis by running lspci -v, which resulted in finding that my USB 3.0 devices, my rtl8169 ethernet chip, and my nVidia GTX 460 were all using the same interrupt (IRQ 16).  Normally sharing IRQs isn’t so bad, so I’m thinking one or more of the drivers has a bug that occurs during idle times.

So, the thought came to me to restart my ethernet interface.  After doing that, my system was back to normal until the next time it happened.  Seeing that my motherboard has two ethernet interfaces, I plan on disabling the RealTek one, and activating the intel one, and see if that resolves it permanently.

]]> http://blog.adamsbros.org/2011/07/21/ubuntu-sluggish-or-slow/feed/ 2 Ubuntu won’t boot raided root http://blog.adamsbros.org/2010/08/14/ubuntu-wont-boot-raided-root/ http://blog.adamsbros.org/2010/08/14/ubuntu-wont-boot-raided-root/#comments Sat, 14 Aug 2010 07:07:44 +0000 http://blog.adamsbros.org/?p=281 Well, I’ve had a lot of trouble switching my system from LVM, to RAID1+LVM on ubuntu 10.04.  I got another drive for my system, created a mirror with one drive (temporarily of course) asked lvm to move my entire system over to that physical device, added the previous drive to the raid array, and rebooted (oops).  I am listing a few things that are important to know when you’re both new to Ubuntu, and doing raid post installation of Ubuntu.

First and foremost, it is very important that you realize the need to run both update-initramfs and update-grub.  update-grub re-configures grub based on your current system configuration.  Things like where /boot resides,  and things of that nature, will be automagically updated in the grub configuration by running update-grub.  update-initramfs takes care of any booting issues you might have post grub, such as raid.  So, any time you make a system change that might affect booting, run these commands before rebooting (thanks to Jordan_U on irc.freenode.org for tips)…

update-grub
update-initramfs -ck all # all kernels and create (not update) the initramfs.

In the event of changing your /boot fs to another location, you should run the following as well.  Thanks again to Jordan_U.

dpkg-reconfigure grub-pc

This ensure that

  1. You can configure the devices that grub will install to
  2. Ubuntu is aware of proper system configurations, for when upgrades occurs and what not, so that it doesn’t write the improper grub.cfg
  3. update-grub is run automatically
  4. installs grub to the devices configured

Now, the particular problem I was having, even though I was running the above commands, is that I kept getting dropped to a shell, with an error that said “ALERT! /dev/mapper/sys-ubuntu does not exist. Dropping to a shell“.   So, as we can see, it was not finding my lvm root system.  So, the big question is “Why?”  Well, after poking around the system a bit, to find out what update-initramfs was doing, I found a file in /usr/share/initramfs-tools/hooks/mdadm that was copying /etc/mdadm/mdadm.conf verbatim to the initramfs.  Well, it’s supposed to “auto detect” my raid arrays, with that configuration, but it doesn’t.  So, the way I fixed it was to run the following commands…

mdadm --detail --scan > /etc/mdadm/mdadm.conf
update-initramfs -ck all

I then rebooted, and my system was very happy, and booted up very quickly. I have since filed a bug report on ubuntu’s launchpad.

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