https://bugzilla.novell.com/show_bug.cgi?id=297737 Summary: Impressive power efficiency possible! (up to 12%) Product: openSUSE 10.3 Version: Alpha 7 Platform: x86-64 OS/Version: openSUSE 10.3 Status: NEW Severity: Major Priority: P5 - None Component: Kernel AssignedTo: kernel-maintainers@forge.provo.novell.com ReportedBy: funtasyspace@yahoo.com QAContact: qa@suse.de Found By: --- Well, I have just played with Intel's PowerTOP tool for some hours to see how openSUSE 10.3 Alpha 7 behaves according to power consumption. I tested this on my Lenovo ThinkPad T60p with openSUSE 10.3 Alpha 7 (x86_64) and KDE 3.5.7 running. I was first a bit disappointed about the 22W - 25W that powertop told me (with AC unplugged), because I remember having read that someone managed about 14,7W on his Gentoo system (also on a T60p). Next I did the following steps: - reduced display brightness to minimum - killed superkaramba - aticonfig --set-powerstate=1 - disabled WLAN, disabled Bluetooth - unpluged LAN-cable - echo 5 > /proc/sys/vm/laptom_mode After those steps I landed around 18,9W - 19,2W. Well, now I was curious about the hint PowerTOP was constantly displaying: "Suggestion: Enable the CONFIG_USB_SUSPEND kernel configuration option. This option will automatically disable UHCI USB when not in use, and may save approximately 1 Watt of power." So I decided to build a modified version of the default kernel by doing a 'make cloneconfig' and ONLY change the option CONFIG_USB_SUSPEND: < #CONFIG_USB_SUSPEND is not set

CONFIG_USB_SUSPEND=Y

I modified the release name (CONFIG_LOCAL_VERSION="-default-usb-suspend") so I could install the new kernel in parallel with the default one, which was shipped with Alpha 7. After compiling and installing the new kernel, I booted openSUSE 10.3 with it and set my system to exactly the same conditions like I wrote above. Et voila, PowerTOP told me that power consumption drooped to 16,6W - 16,9W. That's impressive! I double checked these results by booting the original kernel again, repeating my measurements and then booting the modified kernel again, repeating my measurements, a second time. The results were identical with the first run! Given that, I can verify now, that setting CONFIG_USB_SUSPEND=y reduces power consumption about 2.3W (= 12%) on my system. Therefore I would recommend delivering the openSUSE 10.3 default kernel with this option set. As far as I can tell, I experience no negative side effects with this option set. PowerTOP recommends setting CONFIG_NO_HZ=y too, but as far as I know, this option is not available on the x86_64 architecture, yet. Regards, Jörg PS: This is actually an enhancement and no bug, but I set the severity to major nevertheless, because the effects can really be considered as major ;) -- Configure bugmail: https://bugzilla.novell.com/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug.