There are times (like this morning for 15 minutes) when the performance of my cc1.4xlarge is horrible and it is not anything running on my instance as evidenced by the aws console monitoring graphs and my own investigation.
It seems like the physical box that it is on is having problems or maybe Xen isn't properly allocating resources.
Are there any tools that will monitor not the "reported" stats on the CPU and disk, but do actual performance tests, e.g. divide some floats 1,000 times and make sure it completes within a typical time, write/read stuff to disk?