<> == Testing is Closed == The RC6 call for testing is now officially closed. We appreciate all of the testing feedback we received. It had a direct impact and influence on our decision to enable plain RC6 by default for Precise. Between the testing feedback we received and interaction with the upstream developers, we were also able to find and fix a handful of RC6 related issues. Kudos to all involved. == RC6 == RC6 is a technology which allows the GPU to go into a very low power consumption state when the GPU is idle (down to 0V). It results in considerable power savings when this stage is activated. When comparing under idle loads with machine state where RC6 is disabled, improved power usage of around 40-60% has been witnessed. As a bonus, when those states are reached, there are additional thermal and power space for both CPU and GPU to go into a more aggressive turbo mode. This can also improve the performance of intensive workloads by around 10%, and a bit more in some cases. The above was taken from an [[http://phoronix.com/forums/showthread.php?68199-Intel-Wants-YOUR-Linux-Questions-Feedback&p=246785#post246785|indepth summary regarding RC6 posted by Eugeni Dodonov]]. == Ubuntu RC6 Status == Up until recently, RC6 was disabled by default for Sandy Bridge systems due to reports of hangs and graphics corruption issues when RC6 was enabled. Intel has now asserted that RC6p (deep RC6) is responsible for the RC6 related issues on Sandy Bridge. Patches were therefore submitted upstream to disable RC6p on Sandy Bridge: * http://lists.freedesktop.org/archives/intel-gfx/2012-February/015131.html * https://lkml.org/lkml/2012/2/23/549 In an effort provide more exposure and testing for these patches, the Ubuntu kernel team has applied them to 3.2.0-17.27 and newer Ubuntu 12.04 Precise Pangolin kernels. We have additionally enabled plain RC6 by default on Sandy Bridge systems so that users can benefit from the improved power savings by default. == How to Test == If you are running Ubuntu 12.04 (Precise Pangolin), we would like to capture any feedback regarding improved power savings for Sandy Bridge users witness while running a 3.2.0-17.27 or newer kernel. More importantly, we want to know of any issues which arise as a result of having RC6 enabled. To test, please follow the instructions below: 1. Boot into 3.2.0-17.27 or newer Ubuntu 12.04 Precise Pangolin kernel 1. Gather System Info (BIOS info, kernel version, VGA info) * sudo dmidecode -t 0 | grep "Version:" * cat /proc/version_signature * lspci -nn | grep "VGA" 1. Install power measuring tools * sudo add-apt-repository ppa:colin-king/powermanagement * sudo apt-get update * sudo apt-get install powerstat 1. Unplug the power from your laptop/netbook and run the following command: * sudo powerstat 1. Note the average power consumption and standard deviation which are shown at the end of the powerstat run 1. If you experience any issues due to RC6 being enabled, please file a bug: * ubuntu-bug linux 1. Reboot into the same kernel but disable RC6. To disable RC6, do the following: * Hold down Left-Shift key to enter the Grub menu on boot * Hit 'e' to edit the kernel command line * Append i915.i915_enable_rc6=0 as a kernel boot parameter * For example: linux /boot/vmlinuz-3.2.0-17-generic <...> quiet splash vt.handoff=7 i915.i915_enable_rc6=0 * Press Ctrl-x to boot 1. Unplug the power from your laptop/netbook and run powerstat again to capture comparative test results with RC6 disabled * sudo powerstat 1. Note the average power consumption and standard deviation (σ) which as shown at the end of the powerstat run 1. Add test results to the Crowd Sourcing Test Results section below === Extended Testing === We would appreciate any extended testing with RC6 enabled. For example, exercising graphics doing normal day to day activities. We are keen to hear about any issues such as hangs or graphics corruptions which are triggered with RC6 enabled. If you experience such issues, please file a bug by running 'ubuntu-bug linux' from a command line. == Issues? File a Bug == If you do experience any issues such as hangs or graphics corruptions due to RC6 being enabled, please let us know by filing a bug. To file a bug, run the following command: * ubuntu-bug linux Please be sure to file a bug and note it in the "Issues" column of the Crowd Sourcing Test Results. Otherwise, we will not know how to contact you in order to help resolve your issue. == Crowd Sourcing Test Results == '''Please enter the results in the table below sorted alphanumerically on the machine name. Thanks!''' || Machine || BIOS Info || Kernel Version || VGA Info || powerstat output (RC6 Enabled) || powerstat output (RC6 Disabled) || Issues (Bug:#####)|| || Acer Aspire 4752 || V2.09 || 3.2.0-17-generic || 8086:0116 (rev 09) || 9.52 W, σ=0.24 || 18.31 W σ=0.25 || Kind of bug Bug:935965 see #11 (Resolved now) || || Apple MacBook Air 4,1 || MBA41.88Z.0077.B0E.1110141154 || 3.2.0-17-generic || 8086:0116 (rev 09) || 7.92 W, σ=0.23 || 13.87 W, σ=0.29 || None|| || Apple MacBook Air 4,2 || MBA41.88Z.0077.B0E.1110141154 ||3.2.0-17-generic X86_64||8086:0116 (rev 09)|| 8.86 W, σ=0.13||11.27 W σ=0.62||None|| || Apple MacBook Pro 8,1 || MBP81.88Z.0047.B26.1110311252 || 3.2.0-18.29-generic-pae 3.2.9 || 8086:0126 (rev 09) || 8.03W, σ=0.08 || 13.05W, σ=0.16 || none || || ASUS N53SV || N53SV.214 || 3.2.0-17-generic || 8086:0116 (rev 09) + 10de:0df4 (rev a1) || 27.03 W, σ=2.29 || 36.54W, σ=0.99 || None || || ASUS N55SF || N55SF.204 || 3.2.0-17.27-generic 3.2.6 || [8086:0116] (rev 09) + [10de:1247] (rev a1) || 28.14 W, σ=0.12 || 35.42 W, σ=0.73 || None || || ASUS UX21E || UX21E.209 || 3.2.5-tunerc6v1-generic || 8086:0116 (rev 09) || 7.16 W, σ=0.86 || 12.22 W, σ=0.63 || none || || ASUS U30Sd || U30Sd.211 || Ubuntu 3.2.0-17.27-generic 3.2.6 || [8086:0116] (rev 09) || 9.47 W σ=0.71 || 16.12 W σ=0.39 || Bumblebee installed and running (means discret card was turned off during tests) || || ASUS UX31E || UX31E.211 || 3.2.0-17-generic || 8086:0116 (rev 09) || 5.50 W,σ=0.40 || 6.21 W, σ=0.77 || Bug [[https://bugs.launchpad.net/ubuntu/+source/linux/+bug/937378|#937378]] hard shutdown -> Fix Released with .27 || || ASUS UX31E || UX31E.210 || Ubuntu 3.2.0-17.27-generic || [8086:0116] (rev 09) || 7.96 W σ=0.04 || 11.01 W σ=0.02 || || ASUS U36SD || U36SD.206 || 3.2.0-17-generic || 8086:0116 (rev 09) || 7.84 W σ=0.02 || 10.97 W σ=0.06 || None || || ASUS X53SV || K53SV.210 || 3.2.0-19.30-generic || 8086:0116 (rev 09) + 10de:0df4 (rev ff) || 17.88 W, σ=2.06 || 32.25W, σ=1.09 || Without Ironhide installed || || Dell Vostro 3450 || A07 || 3.2.0-17-generic || 8086:0116 (rev 09) || 11.62 W, σ=0.18 || 17.64 W σ=0.38 || None || || Dell Inspiron N5100 || A02 || 3.2.0-17-generic || 8086:0116 (rev 09) || 20.19 W, σ=0.44 || 24.98 W σ=0.47 || || || HP Pavilion dm4-2120ss || F.12 || 3.2.0-18.28-generic 3.2.9 || 8086:0116 (rev 09) || 9.04 W, σ=0.05 || 14.16 W σ=1.66 || None || || HP Pavilion Dv6-6030el || F.1A || 3.2.0-19.30-generic 3.2.11 || [8086:0116] (rev 09) + [1002:6760] || 16.55W, σ=0.43 || 20.08W, σ=1.17 || None || || Lenovo Edge E420 || 8HET40WW(1.22) || 3.2.0-17-generic-pae || 8086:0126 (rev 09) || 13.43 W, σ=0.36 || 19.92 W σ=0.27 || None || || Lenovo L520 || 8GET38WW (1.15) || 3.2.0-17-generic || 8086:0126 (rev 09) || 12.81 W, σ=0.55 || 28.27 W σ=2.73 || None || || Lenovo T420s|| 8CET50WW (1.30) || 3.2.0-17-generic x86_64|| 8086:0126 (rev 09) || 8.91 W, σ=0.05 || 17.60 W, σ=0.07 || rc6 enabled manually for a long time; occasionally got the whole screen black with 1/4 of it blue (on the right), forcing me to restart, but not sure I can blame that on rc6 || || Lenovo T420 || 83ET63WW (1.33 ) || 3.2.0-17-generic x86_64||[8086:0116] (rev 09) || 8.91 W, σ=0.05 || 13.17W, σ=0.31 || || Lenovo U300s Ideapad || 56CN38WW || 3.2.0-17-generic || 8086:0016 (rev 09) || 14.87 W σ=0.91 || 19.84 W σ=1.12 || None || || Lenovo X201 || 6QET68WW (1.38) || 3.2.0-17-generic || 8086:0046 (rev 02) || 6.40 W σ=0.17 || 6.54 W σ=0.70 || RC6 manually enabled by kernel flag. May not have worked (pre-Sandy Bridge)|| || Lenovo X220 || 8DET56WW (1.26) || 3.2.0-17-generic || 8086:0126 (rev 09) || 7.95 W, σ=0.10 || 15.95 W, σ=0.08 || || Lenovo X220 || 8DET54WW (1.24) || 3.2.0-17.26 || 8086:0126 (rev 09) || 6.66 W, σ=0.18 || 12.09 W, σ=0.16 || Minor graphic issues, e.g. occasionally leaving the topmost window unrefreshed. || || Lenovo X220 || 8DET54WW (1.24) || 3.2.0-17.27 || 8086:0126 (rev 09) || 6.67 W, σ=0.11 || 12.09 W, σ=0.16 || All graphic issues have disappeared. '''Works perfectly.''' || || Lenovo X220 || 8DET55WW (1.25 ) || 3.2.0-17-generic || 8086:0126 (rev 09) || 7.93 W, σ=0.77 || 14.80 W, σ=0.45 || || Lenovo X220 || 8DET56WW (1.26) || 3.2.0-17-generic-pae || 8086:0126 (rev 09) || 9.16 W, σ=0.11 || 13.52 W, σ=0.08 || || Lenovo X220i || 8DET54WW (1.24)||3.2.0-17-generic X86_64||8086:0116 (rev 09)||8.60 W, σ=0.04||9.74 W, σ=0.11|| none || || Lenovo X220i || 8DET54WW (1.24)|| 3.2.0-17-generic #27-Ubuntu x86_64||8086:0116 (rev 09)|| 8.84 W, σ=0.03 || 17.06 W, σ=0.08|| none (re-test) || || Lenovo X220t || 8DET56WW (1.26 ) || 3.2.0-17-generic-pae || 8086:0126 (rev 09) || 7.99 W, σ=0.12 || 17.66 W, σ=0.37 || || Lenovo X220T (with SSD) || 8DET56WW (1.26 ) || 3.2.0-17.27-generic || 8086:0126 (rev 09) || 8.07 W, σ=0.24 || 13.45 W, σ=0.67 || || Samsung NP300V3A || 03FI ||3.2.0-17-generic X86_64 (in Oneiric) ||8086:0116 (rev 09)|| 8.18 W, σ=0.72||11.85 W, σ=2.36|| On an up to date Precise – none || || Samsung NP350U2A || 05PY.M020.20120105.WZW || 3.2.0-17-generic || 8086:0116 (rev 09) || 7.50 W, σ=0.36 || 11.52 W σ=0.82 || Bug Bug:935965 (Resolved in 3.2.0-17.27) || || Samsung NP700Z5B-W01UB || 09/06/2011 (03FD) ||3.2.0-17-generic X86_64||8086:0116 (rev 09)||not tested||not tested|| Severe graphical glitches (tearing) Bug Bug:935965 (Resolved in 3.2.0-17.27) || || Samsung NP900X3BA01US || P03AAH || 3.2.0-18-generic x86_64 || 8086:0116 (rev 09) || 8.46, σ=0.20 || 7.69 W, σ=0.29 || none || || Sony VAIO Z (VPCZ21AJ) || R0170H5 06/16/2011 || 3.3.0-999-generic X86_64 (Daily-Build) || 8086:0116 (rev 09) ||9.09W, σ=0.14 || 15.45W, σ=0.44 || none || || System76 Gaz''''''P6 || 4.6.4 || 3.2.0-17.27-generic || [10de:0dd1] (rev a1) || 33.52W, σ=0.26 || 35.79W, σ=0.55 || none || || Toshiba Satellite R830 1DG || 3.60 || 3.2.0-17-generic X86_64 || 8086:0126 (rev 09) || 11.13W, σ=1.75 || 16.18W, σ=0.42 || none || || Dell Vostro 3450 || A07 || 3.2.0-17.27-generic 3.2.6 || [8086:0116] (rev 09) || 26.54W, σ=2.74 || 36.34W, σ=3.58 || none || || Dell Latitude E6420 || A06 || 3.2.0-18.29-generic 3.2.9 || [8086:0126] (rev 09) || 10.36W, σ=0.30 || 16.17W, σ=0.16 || none || ---- CategoryTestingReport oddly the power was greater for me with it enabled on a new samsung series 9 -Ram