What is the fastest filesystem to use under Linux on EC2 for MySQL?

I've found MySQL fairly slow on EC2 and I am sure it is disk speed. My EC2 install is a test environment so I don't need to keep the data if a block should fail which I think allows me to use XFS.

So....What is the fastest filesystem to use under Linux on EC2 for MySQL?

EDIT: I am using EBS, also I am looking to see if anyone has experience outside of EXT3 as that is what I already find slow

ext2 will be the fastest (and cheapest) filesystem. No need for the journaling of ext3, since the database already takes care of that on its own.

Also, what the user "someone" said is correct. The drive will be faster if you initialize it first. However, if you plan to take snapshots, keep in mind that initializing, even with 0s, will make the snapshots bigger (and therefore more expensive), because now all the blocks have changed.