Making the ASUS Eee 901’s Atom CPU run faster under Ubuntu
Originally published at Dom's Blog. You can comment here or there.
Looking in to the options for the new ASUS netbooks available, I noticed that my Eee 901’s CPU frequency is half that which it should be at, 800 MHz instead of 1600 MHz. This might explain why scrolling webpages is often very slow.
Running the command
while /bin/true ; do grep MHz /proc/cpuinfo ; sleep 1 ; done
shows that I have two virtual CPU cores (due to hyperthreading) which don’t spend a lot of time at the higher frequency. The range can be seen after installing the Ubuntu package “cpufrequtils” and “libcpufreq0″ and then running the command
sudo grep "." /sys/devices/system/cpu/cpu0/cpufreq/*
scaling_max_freq:1600000
scaling_min_freq:800000
I continued reading Ubuntu bug #367739, which is located here, a suggestion was to simply change the threshold at which the cpu frequency is stepped-up to the higher value, since it appears that the system is going over the 95% threshold very often, but 25% seems to be a much more reasonable value.
The solution presented is to add the following (before the “exit” line) to /etc/rc.local - note that the package “libcpufreq0″ is required for this.
sleep 30 # Wait for the ondemand governor to be fully load echo 25 > /sys/devices/system/cpu/cpu0/cpufreq/ondemand/up_threshold echo 25 > /sys/devices/system/cpu/cpu1/cpufreq/ondemand/up_threshold
This appears to make the laptop much more responsive, and the earlier while loop seems to show it spends longer at the higher frequency, so I’ll leave this in place for now, especially as scrolling webpages is much smoother now.