Improving battery life on the HP Mini

A few weeks ago I wrote about my experience using an HP Mini netbook - well in this follow up article describes how I reduced the power consumption on this device with some fairly basic steps.

I started from a fresh clean install of Ubuntu Karmic 9.10 (32 bit) and pulled in all the latest updates. I then installed powertop using:

apt-get install powertop

Then I unplugged the power and let powertop run for 10 minutes to settle in and then noted that ACPI power estimate was ~13.0W.

My first saving was to totally disable Bluetooth - wireless power savings are a good way of saving power. I don't use Bluetooth at all and to save memory from the driver being loaded I blacklisted the btusb module by adding btusb to /etc/modprobe.d/blacklist.conf (this is rather a heavy handed approach!). I then rebooted and re-measured the power consumption - down to 9.7W.

My next tweak was to enable laptop mode. To do this, edit /etc/default/acpi-support and set ENABLE_LAPTOP_MODE=true. Not sure if this is a big win for devices with SSD like my netbook, I believe one will see a bigger power saving with HDD based devices using this setting.

I noted that powertop was informing me to use usbcore.autosuspend=1 and disable hal polling, so I'd thought I'd follow it's wisdom and make these tweaks.

I edited /etc/default/grub and changed the GRUB_CMDLINE_LINUX_DEFAULT setting by adding usbcore.autosuspend=1, and then ran sudo update-grub to update /boot/grub/grub.cfg.

Next I ran:

sudo hal-disable-polling --device /dev/sdb

..for some reason /dev/sdb was being polled and I don't require this overhead for some auto sensing functionality.

I rebooted and remeasured the power consumption - down to 8.7W. Not bad.

Next I totally disabled compiz and turned my display brightness down - this saved 0.3W, bringing the the system down to a reasonable 8.4W. I'm not sure if the compiz savings were much, but if I can save the GPU work by turning off compositing then that must save some power.

My final tweak was to disable the Gnome terminal cursor from flashing - this saves 2 wakeups a second (not much!). To disable the cursor blink for the Default profile I ran gconf-editor and set /apps/gnome-terminal/profiles/Default/cursor_blink_mode to off. This saving is negligible, but makes me feel good to know I've saved two wakeups a second :-)

So now my machine was in a usable state, and down to 8.4W. I could tweak my access point to reduce the number of beacon intervals to save Wifi wakeups, but that's going a little too far, even for me! I then wondered much power Wifi was using, so I disabled it and after 15 minutes my system dropped down to 7.3W. This is good to know but a little pointless for my normal work pattern when I need net access - it is a netbook after all!

I'm sure I can save a little more power, but for now it's a good win for a little amount of work. I'm open to any suggestions on how to save more power. Please let me know!

Netbook computing a success!

OK, I've nearly completed 2 weeks just using a Netbook and I think it's a complete success. The experiment using a HP Mini 1000 running an Alpha version of Ubuntu Karmic proved I can get by without the need of a bulky and power hungry Laptop for all my day-to-day work.

The netbook worked out especially useful while I attended Linux Plumbers in Portland. It's light, compact and I got a reasonable amount of up-time as long as I judiciously used suspend/resume.

Will I be dumping my Lenovo 3000 N200 laptop? Possibly not, but I'm convinced netbooks are the way forward for easy portable mobile computing.

Using the noop I/O scheduler

Over the past few days I've been tweaking the configuration on my HP Mini 1000 to see how to squeeze a little more performance out of this device. Today I enabled the NOOP I/O scheduler on the SSD as this improves performance a little.

Since the SSD is just a flash memory based device, it has minimal seek time and zero rotational delay, so it's sensible to disable the more complex default cfq I/O scheduler and just use the simpler NOOP scheduler. The NOOP scheduler just puts all I/O requests into an unordered First-In First Out (FIFO) queue, and can also do request merging. The rationale behind this is that I/O performance optimisation is performed by the block device such as the logic in the SSD controller.

Traditional hard disks have the overhead of head movement seek times and also rotational delay and it makes sense for these devices to try and group I/O requests together if they are physically close on the disk. However, with SSDs this does not make sense as these delays don't apply - the NOOP I/O scheduler is a better choice as it removes the grouping of I/O requests and hopefully reduces the variability in timing of I/O request completion.

To enable the NOOP I/O scheduler on SDD device /dev/sda, I used (as root):

echo noop > /sys/block/sda/queue/scheduler

..and of course this should be placed in the appropriate boot scripts.

More netbook ramblings

So, I'm now waiting in an airport lounge at London Heathrow Terminal 3 and blogging away using my HP Mini 1000 netbook. It's working out to be a good experience - it's light and portable enough to get through customs without lots of hassles.

Last night I copied about 5 Gigs of audio/video media to the netbook to keep me occupied during my flight across the pond to Portland, USA. I've dumped all the data onto a SDHC flash card as I'm running a little low of free storage space. Originally I started out with a 60GB HDD, but now I've swapped to a 16GB SSD to see if this helps extend battery life, hence I'm now using an SDHC flash card to boost my storage a little. I think this makes sense - for data that I use infrequently it's cheaper to store on a flash card rather than spending lots of money on a larger SSD.

So that's about it for now. I'd better go and catch my plane...

Working on a Netbook

Well, day #3 with working from a netbook and so far things aren't too bad.

Getting the broadcom driver installed using Jockey was a little painful, mainly because I required network access via the Ethernet NIC but for some reason the PCI address space for this device did not get configured correctly unless one booted with acpi=none. Once I had figure a work around, installing the proprietary driver was a breeze.

I'm using the netbook on my desk with a 22" Iiyama flat screen monitor at a resolution of 1680x1050 using the HP mini video -> VGA dongle as shown below:

Not too bad, except for that fact that output has a very slight green tinge to it, which is a not brilliant.

The video dongle is tricky to get hold of, and is required because the video port is a rather slim connector. So, a saving on space on the netbook using a smaller form factor video socket means that we need a special VGA cable which adds more cabling to my desk.

When being used in "desktop" mode, I use a full sized USB keyboard and a wireless mouse, but these use up all the two available USB ports. This is a pain when I want to copy data to USB pen drives; the solution is to use a USB hub but this leaves me with a few more cables on the desk.

Speed wise, it's OK for Email, and Web browsing, I'm used to a speedier laptop so it's a little painful at times when I want a snappy response, for example, editing photos for this blog in Gimp is a bit of a memory and CPU killer.

Downsizing to a Netbook

Over the past 20 months or so I've been lugging my Lenovo 3000 N200 laptop with me around the world when I attend various conferences, Sprints and the Ubuntu Developer Summits. While travelling, I generally use it for Email, Web, IRC, Skype and note taking - which are netbook type activities. If I need to build and kernels I will ssh into an appropriate build server at home and grind code on a far more capable build box. With my neck playing me up, I don't really want to carry a heavy laptop if I have to.

So, it's time to move over to a netbook - the plus point is that it's much smaller and lighter (which is good since I'm not to carrying heavy objects at the moment) - however the downside is that the HDD is smaller and the screen is only 10" and the processor has easily half the compute power as my Lenovo.

My experiment is to see if I can use a netbook over the next week or two and see if it makes my Lenovo redundant.

The first step was to install the latest Ubuntu Karmic Alpha onto my HP Mini 1000 netbook. I could have opted for the Ubuntu Netbook Remix but I personally like using the normal desktop distro (call me old-fashioned!) so I installed the 32 bit Karmic Alpha 5 (since 64 bit won't work on Atom based processors). I pulled in the latest updates and I'm running the latest kernel which I know for sure gets the audio working correctly. I'm using the broadcom wl closed source wireless driver which required just a little bit of attention to install, but all in all it's fairly straight forward.

After installing my normal apps that I need for work I then transferred my home directory over from my Lenono to the netbook and that was about that. I've made some minor tweaks to alter the panel sizes and tweak the fonts just to squeeze in more text onto the screen, but that's about it.

The 1.6GHz Atom N270 processor is fast enough for Skype and also watching the BBC iplayer - although the rendering is a bit choppy when there is a lot of motion, but it's OK enough for casual usage. The integrated webcam works fine and picture quality is most reasonable.

The keyboard is 92% the size of a normal laptop keyboard, so it's quite usable. Even with my chubby fingers it's fine to use - I'm currently writing this blog entry with it without any finger pain.

Suspend/Resume works reliably and fairly fast too. When one opens the netbook lid the resume occurs so quickly that the only clue that it was suspend is seeing the wireless re-associate. So Kernel Mode Setting seems to help in the overall suspend/resume experience.

Email in Evolution is usable, but I could do with more pixels - the 1024x600 TFT display can make things a little cramped. As for battery, I'm getting over 3 hours without any powertop tweaks; I hope to get a better result with some tweaking. I could have opted for an SSD rather than using a HDD to extend battery life, but I needed the larger disk capacity for some of the work I carry around with me.

Tomorrow, I'm going to see how well an external monitor works with this netbook to see if it can be used for my normal desktop tasks. Since most of the day I'm ssh'd into my servers, I don't need a powerful desktop, so it will probably work.

I will let you know if it's thumbs up or thumbs down.