The overall performance of Ubuntu Linux is fine but to further tune the following can be done :
1. If you are not using IPv6 it can be disabled as follows:
In /etc/modprobe.d/aliases change the line alias net-pf-10 ipv6 into alias net-pf-10 off #ipv6.
2. Start daemon/processes in parallel
Change /etc/init.d/rc from CONCURRENCY=none in CONCURRENCY=shell
3. Add your hostname in the host file (default on hardy & intrepid). If you add your host name to the /etc/hosts file some apps will start quicker. e.g. 127.0.1.1 myhostname
4. Install preload. Startup times on apps. can be further improved by installing preload (apt-get install preload)
5. Decrease Swappiness setting
If you got plenty of ram (>1GB) you can decrease the use of the swap file by changing the vm.swappiness sysctl entry from 60 to 10. If you like to further reduce swapfile usage you can set this value to 0* which will not disable swapfile usage but will reduce it to the absolute minimum. To change the sysctl entry *sysctl vm.swappiness=10 can be used, to let this setting survive a reboot vm.swapiness=10 can be added to the /etc/sysctl.conf file.
I’ve found that the value of 5 works very good for my use and I have 2 GB of memory.
6. Use the profile option of grub to reduce startup time.
Hit the escape button when booting to get to the grub menu, select the default kernel and select edit, add the profile option to the end of the kernel line and boot your system.
8. Disable unused services.
9. Use the noatime mount option to disable updating the access time on files.
If you have additional tips I’m more then willing to test/add them to this list.