Some things are surprising. My system has been feeling sluggish and I’ve been cleaning out stuff, fixing things, etc to make things more peppy on my 2 year old netbook which has been upgraded to each new version of Ubuntu Desktop. I was looking at the output of the free command a couple of days ago and found something odd. It showed swap being used. Not much, but I still had currently free memory. I know that can happen, but I was curious anyway.
Since the tendency to swap things out is controlled by the swappiness system variable I took a look and found it was set to 60 out of 100. I did some more searching and found the SwapFaq on help.ubuntu.com.
Interesting reading. It suggests that for a desktop a value of 10 is great.
You can check your swappiness by running
sudo sysctl vm.swappiness
To change the setting, I like to use the sysctl command but you can also cat into the proc file mentioned above.
sudo sysctl vm.swappiness=10
Make it permanent by adding/setting vm.swappiness=10 in /etc/sysctl.conf.
I made the change and the system has not been taking as long when switching between tasks. What surprises me is that the FAQ suggests this is a good setting for a desktop, but Ubuntu Desktop still ships with swappiness=60.