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Wednesday, October 26, 2011

Custom 64 bit Ubuntu Kernel 3.1 optimized for i3, i5 and i7


Kernel 3.1

I built the 64bit kernel 3.1 for my Kubuntu 11.10 desktop optimized for i7. Here is the screenshot of the kernel in action


Feel of the new kernel 3.1 seems to be very exciting. Kubuntu booted to login screen within 10 seconds. (With default kernel it took more than 20 seconds to boot Kubuntu 11.10 unlike ubuntu 11.10 which was faster to boot)

Here is how I built the kernel 3.1 Ubuntu way (in short 7 steps)

In brief
  1. Install build dependencies
  2. Download kernel source and ubuntu patches
  3. Extract and apply ubuntu patches
  4. Create a new flavour and tweak kernel config
  5. Modify Makefile for optimization
  6. Build
  7. Reboot and Enjoy

In detail

Install build dependencies

Open terminal/konsole and execute the following apt-get commands if you don't have essential build packages necessary for building kernel from source in Ubuntu


#Install Build essential to build kernel

sudo apt-get install fakeroot build-essential crash kexec-tools makedumpfile kernel-wedge libncurses5 binutils-dev libelf-dev libdw-dev libnewt-dev libncurses5-dev



sudo apt-get  --no-install-recommends install asciidoc xmlto

Download kernel source and ubuntu patches

Download the source of newly released linux kernel 3.1. The following wget -c makes it simple to download from commandline


#Download kernel source



wget -c http://www.kernel.org/pub/linux/kernel/v3.0/linux-3.1.tar.bz2


Here is how to download the 3.1 ubuntu patches

#Download ubuntu patches
wget -c http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.1-oneiric/0001-base-packaging.patch
wget -c http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.1-oneiric/0002-debian-changelog.patch
wget -c http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.1-oneiric/0003-default-configs.patch


Extract and apply ubuntu patches

Extract downloaded kernel source and apply patches. Here I used tar to unzip the bzip tarball and patch to apply the patch


#Extract kernel source



tar xjvf linux-3.1.tar.bz2


#Create a soft link 

ln -s linux-3.1 linux


#Enter linux directory

cd linux

#Apply the patches

patch -p1 < ../0001-base-packaging.patch 
patch -p1 < ../0002-debian-changelog.patch 
patch -p1 < ../0003-default-configs.patch


Create a new flavour and tweak kernel config

Before creating a new flavor, give execute permissions to debian build scripts for building the kernel properly


#make debian/rules as executable

chmod -Rv +x debian/rules

#make debian/scripts directory executable

chmod -Rv +x debian/scripts/

To create a new flavour, just clone from generic flavor, here is how

#create i7 flavor
cp debian.master/config/amd64/config.flavour.generic debian.master/config/amd64/config.flavour.i7

Do the kernel configuration, I selected processor type as CORE2 and kernel frequency to 1000HZ (just give y only to the newly created flavor when executing editconfigs)


#clean
fakeroot debian/rules clean
fakeroot debian/rules updateconfigs
#give y only to i7 flavor, leave the rest untouched
fakeroot debian/rules editconfigs

Copy the abi related files from existing generic flavor and tweak to reflect the newly created flavor

#copy the abi entries for i7 flavor and add i7 entries in vars and amd64.mk
cp debian.master/abi/3.0.0-12.20/amd64/generic debian.master/abi/3.0.0-12.20/amd64/i7
cp debian.master/abi/3.0.0-12.20/amd64/generic.modules debian.master/abi/3.0.0-12.20/amd64/i7.modules
sed -i s/getall\ amd64\ generic\ server\ virtual/getall\ amd64\ generic\ server\ virtual\ i7/g debian.master/etc/getabis
sed -i s/\=\ generic\ server\ virtual/\=\ generic\ server\ virtual\ i7/g debian.master/rules.d/amd64.mk
cp debian.master/control.d/vars.generic debian.master/control.d/vars.i7
sed -i s/\"Generic\"/\"core\ i7\"/g debian.master/control.d/vars.i7



Modify Makefile for optimization

This is the place where we apply the optimizations. Ubuntu 11.10 comes with gcc 4.6 which has added new architectue corei7


#edit arch/x86/Makefile and arch/x86/Makefile_32.cpu if you want to tweak the march and mtune params of gcc

vi Makefile

vi arch/x86/Makefile

vi arch/x86/Makefile_32.cpu

In the main makefile, I changed HOSTCC and HOSTCXX to look as follows


HOSTCC       = gcc -march=corei7 -mtune=corei7 -pipe

HOSTCXX      = g++ -march=corei7 -mtune=corei7 -pipe



In other makefiles, replace lowercased core2 with corei7 (simple isn't it?)

Build

Do a clean build


#clean and build

fakeroot debian/rules clean



The following builds the common header and source debs

skipabi=true skipmodule=true fakeroot debian/rules binary-indep

The following builds the newly created flavor. Note I added no_dumpfile=yes as it was not building the dumpfile.

time skipabi=true skipmodule=true no_dumpfile=yes fakeroot debian/rules binary-i7

Wait for sometime (depends on speed of your processor). No need to tweak concurrency settings, which are taken care automatically. Install the newly built debs as follows after going one directory above

cd ..

sudo dpkg -i linux-headers-3.1.0-030100_3.1.0-030100.201110241006_all.deb linux-headers-3.1.0-030100-i7_3.1.0-030100.201110241006_amd64.deb linux-image-3.1.0-030100-i7_3.1.0-030100.201110241006_amd64.deb

Reboot and Enjoy

To test the newly built kernel, reboot and select the newly installed kernel from grub. If the newly installed kernel does not boot for some reason, do not panic, select the old ubuntu kernel and boot. (Grub2 does not wait beyond 3 seconds if there is no other OS present and very annoying, press escape within first 3 seconds to display the grub menu if it does not display) Follow this to know more about how to customize grub2 http://maketecheasier.com/mastering-grub-2-the-easy-way/2009/11/19

or

https://wiki.ubuntu.com/Grub2

sudo reboot

Download links

I have uploaded the kernel 3.1 debs which I built and use.  If you don't want to build yourself you can try these.

Here are the SHA256SUM checksum


8d1c58d614056b3cb2e05562d1108cd0a25aa7900ea02f602e8da7a6ead00c83  buildscript.sh

3cbd100b33734330f6b4da7a25cce5c0a45db9cee16bf609c554cbc9cd7b3f98  linux-headers-3.1.0-030100_3.1.0-030100.201110241006_all.deb

6ad9338017182590ef791ed12bbcaf0857090fb6028ec90b6d81ea04c38948f5  linux-headers-3.1.0-030100-i7_3.1.0-030100.201110241006_amd64.deb

e1d62da1add7bfc0b9976fac7d8be32512da8eb09c5b41a6ab66b8c43d12b52e  linux-image-3.1.0-030100-i7_3.1.0-030100.201110241006_amd64.deb

Here are the download links



at 9:20 AM
Posted by Sankaran
Labels: , ,

44 comments:

  1. AnonymousOctober 27, 2011 at 5:45 PM

    And of course don't forget to run "sudo update-grub" before rebooting. It will save you some valuable time I just found out ;)

    ReplyDelete
  2. hartTamaleOctober 28, 2011 at 10:50 PM

    Worked perfectly! Thanks.

    ReplyDelete
  3. And4moreOctober 29, 2011 at 11:07 PM

    Great blog! I have an i3-380m processor running linux mint debian, are there any changes that I need to perform to the above to install the 3.1 custom kernel. At present I use the 2.6.32-5 kernel it's stable but slow.

    ReplyDelete
  4. SankaranOctober 30, 2011 at 10:51 AM

    You need to call sudo update-grub after calling sudo update-initramfs

    ReplyDelete
  5. SankaranOctober 30, 2011 at 1:58 PM

    you could give this kernel a try, this maybe fast, but debian's kernel, well there is no match for anything coming out from debian they are solid, strong and fast

    ReplyDelete
  6. SankaranOctober 30, 2011 at 2:02 PM

    Main advantage I see in this kernel 3.1 (or 2.6.33 and above) over 2.6.32 is TRIM is enabled for SSD. Autogroup scheduling is another big feature. No big Kernel lock in latest kernels. Lots and lots of such advantages.

    ReplyDelete
  7. And4moreOctober 31, 2011 at 1:35 AM

    Thanks for the tech advice, i'll give the 3.1 custom a try!

    ReplyDelete
  8. donzNovember 3, 2011 at 7:13 AM

    Having hard time follow how u do kernel build.

    Just wishing/wanting simple step by step process how it done .

    using Debian 6.03 amd64 with Core2dual cpu

    ReplyDelete
  9. toniNovember 6, 2011 at 8:19 PM

    can show how compile also kde 4.7.3 for i7?

    ReplyDelete
  10. Baban GaigoleJanuary 7, 2012 at 4:48 PM

    I will give it a try though i doesnt seem that simple...

    ReplyDelete
  11. AnonymousJanuary 10, 2012 at 11:54 AM

    thanks for kernel linux install guides in my ubuntu.

    ReplyDelete
  12. Jonathan DrayApril 15, 2012 at 12:14 AM

    Can you please give some instructions on how to apply these optimizations on an official debian kernel ? I'm using instructions found on the debian wiki to recompile the kernel : http://wiki.debian.org/HowToRebuildAnOfficialDebianKernelPackage
    Thank you

    ReplyDelete
  13. SankaranApril 15, 2012 at 4:37 PM

    Ok, I will check the wiki, need some time to install debian directly or inside virtualbox

    ReplyDelete
  14. SankaranApril 15, 2012 at 9:55 PM

    Installed Debian Squeeze 6.0.4, using live usb image,:)

    Now need to download all build essentials before proceeding to build kernel ... will update soon

    ReplyDelete
  15. LeandroMay 15, 2012 at 8:08 PM

    I noticed that if I compile the kernel the Core i7 frequency don't go to it's minimum while idle that's 800MHz. it stays, even idle, at 2.2GHz and with TurboBoost enabled, so it will make the dynamic overclock, but it wont underclock

    ReplyDelete
    Replies
    1. LeandroMay 15, 2012 at 11:23 PM

      Stock kernel underclocks normally, while the compiled even with untouched configs not. I used i7z to check frequencies and PowerTOP V2.0 and proved the underclock problem. Forgot to say it on the previous post.

      Delete
  16. LeandroMay 16, 2012 at 6:38 AM

    What I detected is this. I have two different readings for the same processor but one comes from cpuinfo_cur_freq and the other one comes from scaling_cur_freq as seen below:

    sudo cat scaling_cur_freq; sudo cat cpuinfo_cur_freq
    800000
    1800000

    What's the true reading? Why with stock kernel it don't happen the frequencies match!

    ReplyDelete
  17. SankaranMay 16, 2012 at 12:02 PM

    Can you check acpi_cpufreq and cpufreq_ondemand are modprobed

    ReplyDelete
    Replies
    1. LeandroMay 16, 2012 at 6:25 PM

      Even on stock, lsmod doesn't show the acpi_cpufreq and cpufreq_ondemand in the list. So I'm not sure how to check it.

      Delete
    2. LeandroMay 16, 2012 at 6:29 PM

      Is it what you asked for?

      cat scaling_driver; cat scaling_governor
      acpi-cpufreq
      ondemand

      Delete
    3. LeandroMay 16, 2012 at 6:32 PM

      cat time_in_state
      2201000 57624
      2200000 2875
      2000000 2297
      1900000 631
      1800000 620
      1700000 709
      1600000 659
      1500000 789
      1400000 793
      1300000 822
      1200000 801
      1100000 977
      1000000 1142
      900000 705
      800000 842189

      Delete
  18. LeandroMay 16, 2012 at 7:16 PM

    With stock kernel, just for comparison, as you can see it's more logical and the readings match, even the one that shows the time_in_state.

    sudo cat scaling_cur_freq; sudo cat cpuinfo_cur_freq
    800000
    800000


    cat scaling_driver; cat scaling_governor
    acpi-cpufreq
    ondemand

    cat time_in_state
    2201000 22259
    2200000 50
    2000000 28
    1900000 57
    1800000 42
    1700000 53
    1600000 55
    1500000 112
    1400000 241
    1300000 280
    1200000 355
    1100000 296
    1000000 403
    900000 1642
    800000 145615

    ReplyDelete
  19. SankaranMay 16, 2012 at 10:11 PM

    I am compiling Kernel 3.3.6 in Ubuntu 12.04, will install and test this ...

    ReplyDelete
  20. LeandroMay 16, 2012 at 10:25 PM

    FYI /proc/cpuinfo

    processor : 0
    vendor_id : GenuineIntel
    cpu family : 6
    model : 42
    model name : Intel(R) Core(TM) i7-2670QM CPU @ 2.20GHz
    stepping : 7
    microcode : 0x23
    cpu MHz : 800.000
    cache size : 6144 KB
    physical id : 0
    siblings : 8
    core id : 0
    cpu cores : 4
    apicid : 0
    initial apicid : 0
    fpu : yes
    fpu_exception : yes
    cpuid level : 13
    wp : yes
    flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts nopl xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx lahf_lm ida arat epb xsaveopt pln pts dts tpr_shadow vnmi flexpriority ept vpid
    bogomips : 4390.25
    clflush size : 64
    cache_alignment : 64
    address sizes : 36 bits physical, 48 bits virtual
    power management:

    ReplyDelete
  21. SankaranMay 16, 2012 at 10:54 PM

    I guess I found out the reason for this difference between stock kernel and compiled kernel.

    Though I assumed ubuntu patches for the version of kernel compiled will have all the options of stock kernel, and I am sure it is wrong

    A stock kernel has more sane and tested config options whereas though ubuntu patches are applied for consecutive kernel may not have!!

    did a diff of ubuntu patched 3.3.6 and stock 3.2.0.24

    diff /boot/config-3.3.6-030306-i7 /boot/config-3.2.0-24-generic

    there are lots of differences, guess we should copy stock kernel config and start from there...

    this should be better if we use base config as LTS kernel config!!

    ReplyDelete
    Replies
    1. LeandroMay 16, 2012 at 11:02 PM

      This comment has been removed by the author.

      Delete
    2. LeandroMay 16, 2012 at 11:04 PM

      But did you check the same difference in reported frequencies from the scaling governor and from the processor in your computer too? Or your compiled kernel matched the reported speeds?
      Delete

      Delete
    3. SankaranMay 16, 2012 at 11:09 PM

      will check now and update

      in stock, it is like this


      sudo cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq ; sudo cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
      1596000
      1596000

      Delete
    4. SankaranMay 16, 2012 at 11:13 PM

      sankaran@sankaran-desktop:~$ sudo cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq ; sudo cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
      [sudo] password for sankaran:
      2661000
      2661000
      sankaran@sankaran-desktop:~$ sudo cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq ; sudo cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
      1596000
      1596000
      sankaran@sankaran-desktop:~$ sudo cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq ; sudo cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
      2661000
      1596000
      sankaran@sankaran-desktop:~$ sudo cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq ; sudo cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
      1596000
      1596000
      sankaran@sankaran-desktop:~$ sudo cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq ; sudo cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
      1596000
      1596000
      sankaran@sankaran-desktop:~$ sudo cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq ; sudo cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
      1596000
      1596000
      sankaran@sankaran-desktop:~$ sudo cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq ; sudo cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
      1596000
      1596000
      sankaran@sankaran-desktop:~$ sudo cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq ; sudo cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
      1596000
      1596000
      sankaran@sankaran-desktop:~$ sudo cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq ; sudo cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
      1596000
      1596000
      sankaran@sankaran-desktop:~$

      Delete
    5. SankaranMay 16, 2012 at 11:14 PM

      The above is with i7 optimized 3.3.6 kernel

      uname -a
      Linux sankaran-desktop 3.3.6-030306-i7 #201205121335 SMP Wed May 16 22:08:56 IST 2012 x86_64 x86_64 x86_64 GNU/Linux

      Delete
    6. SankaranMay 16, 2012 at 11:15 PM

      I see background image is rendered very very crisp and color representation is superb with i7 optimized kernel, maybe it is my placebo effect

      Delete
    7. SankaranMay 16, 2012 at 11:21 PM

      I wrote a script to print all 8 cpu differences,

      for i in 0 1 2 3 4 5 6 7; do echo "CPU $i"; sudo cat /sys/devices/system/cpu/cpu$i/cpufreq/scaling_cur_freq; sudo cat /sys/devices/system/cpu/cpu$i/cpufreq/cpuinfo_cur_freq; echo "*** *** ***"; done

      output is
      -----------------------------

      CPU 0
      1596000
      1596000
      *** *** ***
      CPU 1
      1596000
      1596000
      *** *** ***
      CPU 2
      1596000
      1596000
      *** *** ***
      CPU 3
      1596000
      1596000
      *** *** ***
      CPU 4
      1596000
      1596000
      *** *** ***
      CPU 5
      1596000
      1596000
      *** *** ***
      CPU 6
      1596000
      1596000
      *** *** ***
      CPU 7
      1596000
      2661000
      *** *** ***

      Delete
    8. SankaranMay 16, 2012 at 11:23 PM

      some more iterations ...


      sankaran@sankaran-desktop:~$ for i in 0 1 2 3 4 5 6 7; do echo "CPU $i"; sudo cat /sys/devices/system/cpu/cpu$i/cpufreq/scaling_cur_freq; sudo cat /sys/devices/system/cpu/cpu$i/cpufreq/cpuinfo_cur_freq; echo "*** *** ***"; done
      CPU 0
      1596000
      1596000
      *** *** ***
      CPU 1
      1596000
      1596000
      *** *** ***
      CPU 2
      1596000
      2661000
      *** *** ***
      CPU 3
      2661000
      1596000
      *** *** ***
      CPU 4
      1596000
      2661000
      *** *** ***
      CPU 5
      2661000
      2661000
      *** *** ***
      CPU 6
      1596000
      2661000
      *** *** ***
      CPU 7
      2661000
      1596000
      *** *** ***
      sankaran@sankaran-desktop:~$ for i in 0 1 2 3 4 5 6 7; do echo "CPU $i"; sudo cat /sys/devices/system/cpu/cpu$i/cpufreq/scaling_cur_freq; sudo cat /sys/devices/system/cpu/cpu$i/cpufreq/cpuinfo_cur_freq; echo "*** *** ***"; done
      CPU 0
      1596000
      1596000
      *** *** ***
      CPU 1
      1596000
      1596000
      *** *** ***
      CPU 2
      1596000
      1596000
      *** *** ***
      CPU 3
      2661000
      1596000
      *** *** ***
      CPU 4
      1596000
      1596000
      *** *** ***
      CPU 5
      1596000
      2661000
      *** *** ***
      CPU 6
      1596000
      1596000
      *** *** ***
      CPU 7
      1596000
      1596000
      *** *** ***
      sankaran@sankaran-desktop:~$ for i in 0 1 2 3 4 5 6 7; do echo "CPU $i"; sudo cat /sys/devices/system/cpu/cpu$i/cpufreq/scaling_cur_freq; sudo cat /sys/devices/system/cpu/cpu$i/cpufreq/cpuinfo_cur_freq; echo "*** *** ***"; done
      CPU 0
      1596000
      1596000
      *** *** ***
      CPU 1
      1596000
      1596000
      *** *** ***
      CPU 2
      1596000
      1596000
      *** *** ***
      CPU 3
      1596000
      1596000
      *** *** ***
      CPU 4
      1596000
      1596000
      *** *** ***
      CPU 5
      1596000
      2661000
      *** *** ***
      CPU 6
      1596000
      1596000
      *** *** ***
      CPU 7
      1596000
      1596000
      *** *** ***
      sankaran@sankaran-desktop:~$

      Delete
    9. SankaranMay 16, 2012 at 11:24 PM

      know what, the reading has human error, between one print and another print, frequency of cpu would have hopped ... so there is a difference

      Delete
  22. SankaranMay 16, 2012 at 10:56 PM

    Till then use LTS kernel, that should be the best kernel next to EL6 kernel

    ReplyDelete
  23. LeandroMay 17, 2012 at 12:04 AM

    This comment has been removed by the author.

    ReplyDelete
  24. LeandroMay 18, 2012 at 7:34 PM

    I made three iteractions of your script. It only asked me about new options that appeared from 3.2.0 kernel to 3.3.6. I'm using config-3.2.0-24-generic original from pricise to compile the 3.3.6 kernel, but I defaulted all of the new options and the difference still appearing.

    leandro@leandro-Dell-L502X: for i in 0 1 2 3 4 5 6 7; do echo "CPU $i"; sudo cat /sys/devices/system/cpu/cpu$i/cpufreq/scaling_cur_freq; sudo cat /sys/devices/system/cpu/cpu$i/cpufreq/cpuinfo_cur_freq; echo "*** *** ***"; done

    CPU 0
    800000
    1800000
    *** *** ***
    CPU 1
    2201000
    2201000
    *** *** ***
    CPU 2
    800000
    1800000
    *** *** ***
    CPU 3
    800000
    2201000
    *** *** ***
    CPU 4
    800000
    1800000
    *** *** ***
    CPU 5
    800000
    1800000
    *** *** ***
    CPU 6
    800000
    1800000
    *** *** ***
    CPU 7
    2201000
    2201000
    *** *** ***
    leandro@leandro-Dell-L502X:/sys/devices/system/cpu$ for i in 0 1 2 3 4 5 6 7; do echo "CPU $i"; sudo cat /sys/devices/system/cpu/cpu$i/cpufreq/scaling_cur_freq; sudo cat /sys/devices/system/cpu/cpu$i/cpufreq/cpuinfo_cur_freq; echo "*** *** ***"; done
    CPU 0
    2201000
    2201000
    *** *** ***
    CPU 1
    800000
    1800000
    *** *** ***
    CPU 2
    2201000
    2201000
    *** *** ***
    CPU 3
    2201000
    1800000
    *** *** ***
    CPU 4
    800000
    1800000
    *** *** ***
    CPU 5
    2201000
    2201000
    *** *** ***
    CPU 6
    800000
    2201000
    *** *** ***
    CPU 7
    800000
    2201000
    *** *** ***
    leandro@leandro-Dell-L502X:/sys/devices/system/cpu$ for i in 0 1 2 3 4 5 6 7; do echo "CPU $i"; sudo cat /sys/devices/system/cpu/cpu$i/cpufreq/scaling_cur_freq; sudo cat /sys/devices/system/cpu/cpu$i/cpufreq/cpuinfo_cur_freq; echo "*** *** ***"; done
    CPU 0
    800000
    1800000
    *** *** ***
    CPU 1
    2201000
    1800000
    *** *** ***
    CPU 2
    800000
    2201000
    *** *** ***
    CPU 3
    800000
    1800000
    *** *** ***
    CPU 4
    800000
    1800000
    *** *** ***
    CPU 5
    2201000
    1800000
    *** *** ***
    CPU 6
    800000
    1800000
    *** *** ***
    CPU 7
    800000
    1800000
    *** *** ***

    ReplyDelete
  25. SankaranMay 18, 2012 at 8:11 PM

    Difference is prone to come, as even a millisecond delay is more than enough for CPU to jump from one frequency to another. There should be more than 10 ms of delay between printing cpuinfo_cur_freq and scaling_cur_freq at the least, so the only way you can confirm is change the governor of cpu to userspace, set to a fixed frequency and see if it is changing

    ReplyDelete
    Replies
    1. LeandroMay 18, 2012 at 10:11 PM

      i made what you told, I set to 800MHz, the minimun for my CPU. Even setting manually, it doesn't go below 1.8GHz. If I set to the maximum frequency, the TurboBoost, one it goes normally to 2.9GHz and every other frequency I set it will obey but the ones below 1.8GHz.

      Delete
    2. LeandroMay 25, 2012 at 4:56 PM

      This comment has been removed by the author.

      Delete
    3. LeandroMay 26, 2012 at 12:55 AM

      Somebody on OpenSUSE forum that had the same problem gave me this tip and it simply worked, now the processor scale down to 800MHz

      add the kernel boot options: i915.i915_enable_rc6=1 i915.i915_enable_fbc=1 i915.lvds_downclock=1 pcie_aspm=force

      Delete
  26. LacerdaSeptember 6, 2013 at 6:08 PM

    Hi there!

    I've been following this blog for a long time, because I have a core i7-Q720 and I run Ubuntu 13.04, and I thank you very much for your efforts to make everything reader-friendly in a tutorial-like manner.
    Yesterday, I came upon a huge news for me: AMD has released (march this year, though) a huge amount of patches concerning power management and hardware acceleration. But these won't be implemented before kernel 3.11, which is already the latest stable kernel out there. I was wondering if these patches had already been implemented or they have yet to be implemented manually.
    I'm sorry if I am asking too much, but would it be possible for you to compile this for me or give the directions for me to compile it myself?

    Thank you in advance,
    Pedro Lacerda

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    Replies
    1. SankaranSeptember 6, 2013 at 7:57 PM

      I am using Kernel 3.10, I will compile 3.11 kernel and upload it

      It is not a problem, had been stuck for long due to graphics drivers issue, I know how it feels ...

      Delete
    2. SankaranSeptember 6, 2013 at 10:22 PM

      I built the kernel 3.11 but have not tested it (have not yet rebooted)

      I have created a blog of the same with download links, which you can test

      http://duopetalflower.blogspot.in/2013/09/custom-64bit-kernel-311-optimized-for-i7.html

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