noatime + BFS + kernel update = win

Lately my laptop was quite slow in terms of performance
It's an old one with a crappy centrino cpu 1.5Ghz and with only 768 mb of memory.
When I was on debian I used a light desktop environment but since I liked ubuntu user-friendly UI I wanted gnome now.
Still I didn't think memory was the problem when I had almost everything closed and around 500mb of mem free.
So I thought It either IO requests of CPU.
So here are some steps which made my system be a bit more responsive:

1. Probably the easiest is the a mount parameter on the file-system.
   The ext3,4 filesystem has a parameter which for mounting with or without access time enabled.
   atime parameter on mount write the timestamps whenever it is reading the file or directory. This makes another step on the reading of every file on the system. You most probably don't need this unless it mess up with news servers etc. which I don't use.
   Tip: You can use realatime parameter for that on latest kernels.
   
   In order to disable this on mount of an ext3,4 file-system we have to mount with the option of noatime on the system:
   On the fly:
   

   $ sudo mount -o remount,noatime /

   or by editing /etc/fstab and adding the noatime on options field:
   

   /dev/sda1 / ext4 errors=remount-ro,noatime 0 1

2. The second thing you can do is change the Process Scheduler. It's a system responsible for manipulating the processes priorities on the kernel. Latest kernel use the CFS (completely fair scheduler)
   The person (Con Kolivas) who inspired the write of CFS wrote lately another one which called Brain Fuck Scheduler and it's more for desktop computers.
   In order to use the BFS we have to recompile the kernel patched with Con Kolivas' patch
   Info can be found on his page but here is what I did:
   First download a stable kernel for which Colivas have a patch on his site
   I choose 2.6.35 since it said to improve btrfs performance as well
   

   $ wget http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.35.tar.bz2
   $ tar xvfj linux-2.6.35.tar.bz2
   $ cd linux-2.6.35
   

   Now we need to patch it with the colivas patch:
   Download the patch for the kernel version you have from site. For my choice:
   

   $ wget http://www.kernel.org/pub/linux/kernel/people/ck/patches/2.6/2.6.35/2.6.35-ck1/patch-2.6.35-ck1.bz2
   $ bunzip2 patch-2.6.35-ck1.bz2

   And now we have to patch the kernel:
   

   $ patch -p1 < patch-2.6.35-ck1

   
   
   
   
   This will change some files on the kernel source. After that the procedure for kernel compilation is common. Just follow directions from Canonical or kernel.org

All and all took me something like an afternoon to learn all those and to compile the kernel on with my old cpu. After that I found out the localmodconfig option of make kernel in order to save some time. :)
Now I have a 2.6.35 kernel with BFS and I can see a difference in a lot of applications. It is quite more responsive that it used to be.