Overclocking

Overclocking
This page is about overclocking the N900. For the N8x0 see this thread on talk.maemo.org

&#x23; WORK IN PROGRESS, HELP IF YOU WANT

Overclocking is discussed in this thread. Benchmark results can be found here. If you're more interested in power saving read this.

Warnings

 * Overclocking WILL VOID YOUR WARRANTY. Your warranty does not cover running the device beyond the specifications.
 * The lifetime of your device may get reduced (see below)
 * Your data might get corrupted (for example, file system corruption)
 * Every device is an individual, what is stable for others might not be for you
 * If you encounter ANY unusual problems, lower your clock frequency
 * You do it at your own responsibility. No whining afterwards. If you're unsure, don't do it.
 * Nokia's overclocking warning: 500MHz is the normal frequency. Everything above is not good for your device, even with the stock kernel.
 * Igor Stoppa's warning and comment
 * chip vendors specs

Lifetime, warranty and damage

 * The expected lifetime all devices is limited due to wear.
 * It is usually much longer (several years) then the warranty period, so that even with heavy use within the specifications it would not fail before warranty ends.
 * With overclocking users may see considerable speed improvements and lower latency in user experience which could extend the actual lifetime (of being used) as the device could keep up with the newer models.
 * Naive overclocking with stock voltages is definitely bad for most components in your device, especially if the device is continuously locked at high frequencies with high load (see TI specs).
 * Specifications give guarantees for the worst-case scenarios that are covered by the warranty. The best-case scenario may be different for every device but is not covered by warranty.
 * However, there is an open debate whether mild (<40%) overclocking with lower voltages (undervolting) does actually harm or is even less harmful than the stock settings.
 * Evidence for or against damages (esp. with undervolting) in the N900 is currently absent and will probably only be available when the device is no longer on the market.
 * Therefore, if you are unsure and you want to avoid potential damages, do not overclock!

Available kernels
Overclocking requires installation of a custom kernel. There are two types of kernels:
 * 1) modified PR1.1 kernels by Lehto and others. The only difference from the stock Nokia kernel is the change of the available hardcoded frequencies.
 * 2) enhanced kernels by titan. They are compatible with PR1.2 (!), contain lots of additional features (IPv6, NAT etc) and bugfixes. In addition they include a large set of possible frequencies (125MHz-1.15GHz) which you manually set and try out without flashing a new kernel. The defaults are set to the standard 250-600MHz range. The kernel can be installed via HAM from the extras-devel catalog.

Jakiman's Guide to Overclocking for Newcomers
Jakiman's Overclock Guide / Summary (constantly updated)

Installation of Lehto's PR1.1 kernels
Lehto's Kernels

Installation of titan's enhanced kernels
This kernel makes it possible to dynamically change the maximum frequency up to 1.15GHz (supported frequencies are 125,250,500,550,600,700,750,805,850,900,950,1000,1100,1150MHz).

see the separate page for this kernel: Kernel_Power

talk.maemo.org: Discussion of the enhanced kernel

Additional information and hints

 * 1) the frequencies available in the Nokia kernel are: 250, 500, 550 and 600MHz.
 * 2) the CPU does NOT IDLE at the lowest frequency (250MHz) but it SLEEPS at 0MHz! Thus reducing the lowest frequency would not reduce power consumption. It is only activated during low workload and may actually consume more power than a higher frequency, as it takes more time to go back to sleep/idle state.
 * 3) setting the lowest frequency to 125MHz does NOT improve battery life. In fact, many people noticed worse battery life, instability and worse responsiveness,
 * 4) Nokia locks the device to 600MHz during phone calls. This may be a bug. It also affects Lehto's kernels.
 * 5) the telephone app is closed-source and broken. After a phone call it sets the maximum to 600Mhz and the minimum to 250MHz (or  125MHz if available) irrespective of what you have set before. The are some workarounds in the Kernel-power kernel.
 * 6) when connected via USB the device locks the minimum frequency to 500Mhz.
 * 7) By default the device is configured to use 125MHz as the lowest frequency but it not enabled in the kernel pmconfig bug
 * 8) improving responsiveness
 * 9) safe pmconfig configuration
 * 10) the warning WARNING: at arch/arm/mach-omap2/clock34xx.c:443 omap3_noncore_dpll_set_rate+0x28c/0x2dc in the kernel logs (dmesg) only happens if the invalid 800MHz frequency was selected. ignore it.
 * 11) saving more battery power when idle
 * 12) EvilJazz had photoshopped a picture of a device being overclocked 1.7GHz. It's a prank!
 * 13) reading one of the temperature sensors "cat /sys/devices/platform/omap34xx_temp/temp1_input"

Show current CPU frequency
awk '{print $1/1000" MHz"}' /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq

Set maximum CPU frequency
From root terminal:

echo "echo 600000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq" | root

Replace 600000 with desired maximum frequency. Pay attention to the two exceptions in titan's kernels (124999 and 599000). The list of available frequencies on your device/kernel can be obtained with command:

awk '{print $1/1000" MHz"}' /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state

Script for analyzing time_in_state (by rooted) - rev7
This script prints percentage of frequencies (states) used and some additional info useful for posting on the forum (debugging). It displays all frequencies, works with all kernels and it is not affected by the bug which resets minimum frequency after phone call.

The script is in active development. I'm adding new features and resolving bugs if they are reported. Please update your script to newest revision and report if something doesn't work properly.

Temperature may not be listed if you don't have module bq27x00_battery installed or enabled. Also kernel-power version is not listed if you don't use titan's kernel.

Output example:

TIME_IN_STATE ANALYSING SCRIPT By rooted (maemo.org) Revision 7

The script is in active development. Update your script to current revision from: wiki.maemo.org/Overclocking

FREQUENCY      USED            WHEN BUSY

1150 MHz       unused 1100 MHz       unused 1000 MHz       unused 950 MHz        unused 900 MHz        unused 850 MHz        unused 805 MHz        4.5 %           58.9 % 750 MHz        0.0 %           0.4 % 700 MHz        0.0 %           0.3 % 600 MHz        0.3 %           3.4 % 550 MHz        0.0 %           0.5 % 500 MHz        2.8 %           36.5 % 250 MHz        92.4 % 125 MHz        unused

Kernel:                 2.6.28.10power37 kernel-power:           2.6.28-maemo37 kernel-power-settings:  0.11 Uptime:                 56 min Load:                   0.25, 0.12, 0.09 Boot reason:            pwr_key Temperature:            31 degrees C

Analyzing time in state, including idle mode stats (by ArbitRabbit)
The following script will show the current frequency and statistics for each state, including time spent in idle mode when the CPU is actually sleeping. This script works with the special frequency handling in Titan's kernel.

To run this script as user and be able to set the frequencies you will need to install "rootsh" via apt-get.

scheduler_stats.sh

Sample Output

Current frequency: 500 MHz

Minimum frequency: 500 MHz

Maximum frequency: 810 MHz

FREQUENCY      USED 1200 MHz       0 % 1100 MHz       0 % 1000 MHz       0 % 950 MHz        0 % 900 MHz        0 % 850 MHz        0 % 810 MHz        0.000 % 750 MHz        0.000 % 700 MHz        0.000 % 600 MHz        0.000 % 550 MHz        0.000 % 500 MHz        0.010 % Time spent in idle mode is 99.99 %

Known Bugs: Requires the Phone to be booted for an hour or so before it results in decent stats.

Combined helper script (by evilJazz)
The following script will show the current frequency and statistics. It also accepts two optional parameters that will set the max and/or min frequencies (in MHz unit). Calling the script without these parameters will not set the new clocking. Instead it will just show the current frequencies and statistics.

This script works with the special frequency handling in Titan's kernel.

To run this script as user and be able to set the frequencies you will need to install "rootsh" via apt-get.

overclock.sh [max freq] [min freq]

Output example:

~ $ ./overclock.sh 600 250

Current frequency:    250 MHz Minimal frequency:    250 MHz Maximal frequency:    599 MHz

1200 MHz:  0.0 % (       0) 1100 MHz:  0.0 % (       0) 1000 MHz:  0.0 % (       0) 950 MHz:  0.0 % (       0) 900 MHz:  0.2 % (     271) 850 MHz:  0.0 % (       0) 810 MHz:  0.0 % (       0) 750 MHz:  0.0 % (       0) 700 MHz:  0.0 % (       0) 600 MHz:  9.0 % (   13663) 550 MHz:  0.5 % (     701) 500 MHz: 15.4 % (   23379) 250 MHz: 75.0 % (  114021) 124.999 MHz:  0.0 % (       0)

Underclock/Overclock when phone is Locked/Unlocked (by Fecn)
When locked, the limits are changed to 250/500Mhz to save power - I don't need my phone to be fast when it's sitting there doing nothing. (I did try with 125Mhz as minimum but it caused an unresponsive touchscreen during incoming phone calls and alarms)

When unlocked, the limits are set for overclocking, with the max speed determined by the temperature ( 1150Mhz is stable on my phone - your mileage may vary - adjust scripts as required)

You need the dbus-scripts package installed for this to work. You also need to add bq27x00_battery to your /etc/modules so that it is loaded at boot time - it needs to be loaded to be able to read the temperature.

We use the dbus-signalling to follow what the phone is doing and fire off scripts to change the limits accordingly.

Create the following two 1-line files inside /etc/dbus-scripts.d/

Filename: /etc/dbus-scripts.d/locked /usr/local/bin/underclock * * com.nokia.mce.signal tklock_mode_ind locked

Filename: /etc/dbus-scripts.d/unlocked /usr/local/bin/overclock * * com.nokia.mce.signal tklock_mode_ind unlocked

... and then create corresponding scripts that they call inside /usr/local/bin/ ( don't forget to chmod them to executable )

Filename: /usr/local/bin/underclock kernel-config limits 250 500
 * 1) !/bin/sh

Filename: /usr/local/bin/overclock TEMP=`cat /sys/class/power_supply/bq27200-0/temp` echo "Temp is :" $TEMP "C" MAXSPEED="1150" if [ $TEMP -gt "38" ] ; then MAXSPEED="1000" ; fi if [ $TEMP -gt "40" ] ; then MAXSPEED="950" ; fi if [ $TEMP -gt "43" ] ; then MAXSPEED="850" ; fi if [ $TEMP -gt "45" ] ; then MAXSPEED="750" ; fi if [ $TEMP -gt "47" ] ; then MAXSPEED="600" ; fi echo "Setting max as :" $MAXSPEED "Mhz"
 * 1) !/bin/sh

kernel-config limits 250 $MAXSPEED

You'll need to restart dbus-scripts for it to see the new configs. I found that the scripts in init.d weren't too good at doing this, so had to kill it manually each time.

If you want to scale your processor speed according to battery capacity in addition to temperature, use an overclock script something like the following:

Filename: /usr/local/bin/overclock TEMP=`cat /sys/class/power_supply/bq27200-0/temp` echo "Temp is:" $TEMP "C" MAXSPEED="1150" if [ $TEMP -gt "38" ] ; then MAXSPEED="1000" ; fi if [ $TEMP -gt "40" ] ; then MAXSPEED="950" ; fi if [ $TEMP -gt "43" ] ; then MAXSPEED="850" ; fi if [ $TEMP -gt "45" ] ; then MAXSPEED="750" ; fi if [ $TEMP -gt "47" ] ; then MAXSPEED="600" ; fi
 * 1) !/bin/sh

BATTERY=`cat /sys/class/power_supply/bq27200-0/capacity` echo "Battery is:" $BATTERY "% full" MAXSPEEDTWO="1150" if [ $BATTERY -lt "60" ] ; then MAXSPEEDTWO="850" ; fi if [ $BATTERY -lt "40" ] ; then MAXSPEEDTWO="600" ; fi if [ $BATTERY -lt "25" ] ; then MAXSPEEDTWO="500" ; fi

if [ $MAXSPEEDTWO -lt $MAXSPEED ] ; then MAXSPEED=$MAXSPEEDTWO ; fi

echo "Setting max as:" $MAXSPEED "Mhz"

kernel-config limits 250 $MAXSPEED

Flashing using PC
note: For Windows7 64bit users, you may need to use WindowsXP mode. (Youtube Tutorial)
 * 1) Power off the N900 completely.
 * 2) Hold "u" on the N900's keyboard, while holding, connect it to the PC via USB cable.
 * 3) You will see usb icon on top right of white Nokia screen.
 * 4) Now you can let go of "u" on the keyboard.
 * 5) Now use flasher utility with the kernel file located in the same directory. flasher-3.5 -k image_file_name -f -R
 * 6) It should take about 1-2 seconds then it'll say Done.
 * 7) Now your N900 will show white Nokia screen. (reboot)
 * 8) At this time, you can pull out the USB cable.
 * 9) N900 should finish booting up if all goes well.
 * 10) Test out your phone as usual. (Apps, browser, camera, phone etc etc)
 * 11) If any abnormal events occur frequently (crash, hang, screen corruption etc), turn it off, flash it to a slower kernel and test again.

Flashing from N900 xterminal

 * do a backup, have a pc nearby and know you are able to flash the n900 with flasher-3.5 - just in case


 * 1) Launch xterminal app then type sudo gainroot (need rootsh installed)
 * 2) type: softupd -vv -s --local (that is a double v)
 * 3) open new terminal
 * 4) type: flasher --local -f -k 
 * 5) you see the flashing (takes some time)
 * 6) type "sync" to save changes
 * 7) type "reboot" and enter to restart
 * 8) Test out your phone as usual. (Apps, browser, camera, phone etc etc)
 * 9) If any abnormal events occur frequently (crash, hang, screen corruption etc), turn it off, flash it to a slower kernel and test again.

'''You are fully responsible for any damage caused by overclocking. Not anyone else.'''

Reverting to the Original Kernel
If you want to revert to the original kernel, execute:

apt-get install --reinstall kernel kernel-flasher

Fixing the version information
If your version information got lost (control panel -> version) you can fix it by reinstalling the package that is listed with: dpkg -l "mp-fremantle*" for example, "mp-fremantle-generic-pr" (for some firmwares 002 or 003 instead of generic) and then execute: apt-get install --reinstall mp-fremantle-generic-pr

Undervolting and voltage tables
See: http://talk.maemo.org/showpost.php?p=628839&postcount=81

Extract from the post:

One factor reducing CPU lifetime is the current it is running with.

(wikipedia:Dynamic_frequency_scaling)

As can be seen from the formula lower voltage plays greater part in CPU consumption than frequency. By reducing the voltage the damage of overclocking can be reduced and the battery life time extended.

Calculating voltages
According to this calculations the voltage can be varied in steps of 0.0125 V with values 0-72. The formula is (with x being the kernel parameter value):

Examples:

Lowest voltage (x = 0):  0  * 0.0125 + 0.6 = 0     + 0.6 = 0.6 V Highest voltage (x = 72): 72 * 0.0125 + 0.6 = 0.9   + 0.6 = 1.5 V Random voltage (x = 38):  38 * 0.0125 + 0.6 = 0.475 + 0.6 = 1.075 V

Summary
FREQUENCY  Nokia   LV    ULV   XLV   ideal 0 MHz      30      30    25    30    30 125 MHz    30      30    25    20    30 250 MHz    38      38    25    30    30 500 MHz    48      48    33    33    30 550 MHz   *54*     48    38    38    33 600 MHz    60     *54*   38    38    38 700 MHz            54    45    45    45 750 MHz            54    45    45    45 810 MHz            54    48    48    48 850 MHz            54    48    48    48 900 MHz            54   *54*  *54*  *54* 950 MHz            54    54    54    54 1000 MHz           60    60    60    60 1100 MHz           72    72    72    72 1150 MHz           72    72    72    72

Note: Asterisks indicate the first frequency in the kernel which needs overvoltage.

/sys/power/vdd1_opps_vsel values
LV:     "30 30 38 48 48 54 54 54 54 54 54 54 60 72 72" ULV:    "25 25 25 33 38 38 45 45 48 48 54 54 60 72 72" XLV:    "30 20 30 33 38 38 45 45 48 48 54 54 60 72 72" ideal:  "30 30 30 30 33 38 45 45 48 48 54 54 60 72 72"

Nokia's kernel
VALUE VOLTAGE   FREQUENCY     DYNAMIC POWER 30    0.975 V   0 MHz         0.000 V²/us 30    0.975 V   125 MHz       118.828 V²/us 38    1.075 V   250 MHz       288.906 V²/us 48    1.200 V   500 MHz       720.000 V²/us 54    1.275 V   550 MHz       894.094 V²/us 60    1.350 V   600 MHz       1093.500 V²/us

titan's LV kernel
VALUE VOLTAGE   FREQUENCY     DYNAMIC POWER 30    0.975V    0 MHz         0.000 V²/us 30    0.975V    125 MHz       118.828 V²/us 38    1.075V    250 MHz       288.906 V²/us 48    1.200V    500 MHz       720.000 V²/us 48    1.200V    550 MHz       792.000 V²/us 54    1.275V    600 MHz       975.375 V²/us 54    1.275V    700 MHz       1137.938 V²/us 54    1.275V    750 MHz       1219.219 V²/us 54    1.275V    810 MHz       1316.756 V²/us 54    1.275V    850 MHz       1381.781 V²/us 54    1.275V    900 MHz       1463.062 V²/us 54    1.275V    950 MHz       1544.344 V²/us 60    1.350V    1000 MHz      1822.500 V²/us 72    1.500V    1100 MHz      2475.000 V²/us 72    1.500V    1200 MHz      2700.000 V²/us

titan's ULV kernel
VALUE VOLTAGE   FREQUENCY    DYNAMIC POWER 25    0.912V    0 MHz        0.000 V²/us 25    0.912V    125 MHz      103.968 V²/us 25    0.912V    250 MHz      207.936 V²/us 33    1.012V    500 MHz      512.072 V²/us 38    1.075V    550 MHz      635.594 V²/us 38    1.075V    600 MHz      693.375 V²/us 45    1.163V    700 MHz      946.798 V²/us 45    1.163V    750 MHz      1014.427 V²/us 48    1.200V    810 MHz      1166.400 V²/us 48    1.200V    850 MHz      1224.000 V²/us 54    1.275V    900 MHz      1463.062 V²/us 54    1.275V    950 MHz      1544.344 V²/us 60    1.350V    1000 MHz     1822.500 V²/us 72    1.500V    1100 MHz     2475.000 V²/us 72    1.500V    1200 MHz     2700.000 V²/us

titan's XLV kernel
VALUE VOLTAGE   FREQUENCY    DYNAMIC POWER 30    0.975V    0 MHz        0.000 V²/us 20    0.850V    125 MHz      90.312 V²/us 30    0.975V    250 MHz      237.656 V²/us 33    1.012V    500 MHz      512.072 V²/us 38    1.075V    550 MHz      635.594 V²/us 38    1.075V    600 MHz      693.375 V²/us 45    1.163V    700 MHz      946.798 V²/us 45    1.163V    750 MHz      1014.427 V²/us 48    1.200V    810 MHz      1166.400 V²/us 48    1.200V    850 MHz      1224.000 V²/us 54    1.275V    900 MHz      1463.062 V²/us 54    1.275V    950 MHz      1544.344 V²/us 60    1.350V    1000 MHz     1822.500 V²/us 72    1.500V    1100 MHz     2475.000 V²/us 72    1.500V    1150 MHz     2587.500 V²/us

titan's ideal kernel
VALUE VOLTAGE   FREQUENCY    DYNAMIC POWER 30    0.975V    0 MHz        0.000 V²/us 30    0.975V    125 MHz      118.828 V²/us 30    0.975V    250 MHz      237.656 V²/us 30    0.975V    500 MHz      475.312 V²/us 33    1.012V    550 MHz      563.279 V²/us 38    1.075V    600 MHz      693.375 V²/us 45    1.163V    700 MHz      946.798 V²/us 45    1.163V    750 MHz      1014.427 V²/us 48    1.200V    810 MHz      1166.400 V²/us 48    1.200V    850 MHz      1224.000 V²/us 54    1.275V    900 MHz      1463.062 V²/us 54    1.275V    950 MHz      1544.344 V²/us 60    1.350V    1000 MHz     1822.500 V²/us 72    1.500V    1100 MHz     2475.000 V²/us 72    1.500V    1150 MHz     2587.500 V²/us