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Tuesday, October 20, 2009

Upcoming Ubuntu Karmic x64 kernel frequency

If you thought that the generic kernel frequency of x64 (amd64) architecture in Ubuntu Karmic is 250 Hz then you are there for a surprise! It is just 100Hz (no no, I want 1000Hz without using a rt kernel). This might change with final build or release candidate build of Ubuntu Karmic

I am having upcoming Ubuntu Karmic 64 bit installed in my system (using its daily live CD)

I checked what is the kernel frequency by using grep on the kernel config file in /boot directory

cat /boot/config-2.6.31-14-generic | grep HZ

 It is still very very snappy with just 100Hz. I checked the kernel frequency in an IBM thinkpad which has 32 bit karmic, but it shows 250Hz (It is an irony that a 32 bit kernel has a 250Hz freq and a 64 bit kernel has 100Hz freq)

This might change with upcoming release candidate of karmic or  final build of karmic


  1. openSUSE 11.2 RC1 has this set to 1000HZ, does that mean it's faster? Do you no what the advantages/disadvantages are of higher HZ settings?

    Btw I linked to you from http://www.ruwebit.net/article/379 (Dutch article).

  2. http://kerneltrap.org/node/5411

    Browse the above kerneltrap link.

    To my understanding, higher kernel frequency means higher responsiveness and lower kernel frequency means lower responsiveness. A 100 Hz means, kernel will fire the timer function 100 times per second, whereas 1000Hz means kernel will fire timer function 1000 times per second. Which means the precision of millisecond timer you get with 1000Hz and 1/10th in case of 100Hz. But there is a big advantage in 100Hz kernel, which is kernel timer only wakes up 100 times per second compared to 1000 times which is good for battery life and long life of processor

    The speed of a dedicated functionality is not affected due to kernel frequency, but the responsiveness to user events will certainly be high when a higher frequency kernel is there. For a game where every millisecond is important for event and a millisecond precision event is wanted, 1000Hz kernel is the way to go.