Is running YUI compressor very load intensive?

Why is it eating开发者_高级运维 up all my CPU like crazy?

load average: 4.60, 4.26, 2.55

Yes, it can be, depending on the engine and compression ratio. The better the end results, the more resources you should expect to have to spend.

Load going to 9.0 from a single process (YUICompressor, anything else) doesn't make a lot of sense. How are you running it? What else is going on concurrently?

The "load average" is a metric that tells you how many processes are waiting for the CPU over some window of time. If you're doing nothing other than running YUICompressor (or any other single program) the load average won't get much bigger than 1 - that means that the compressor is mostly using the CPU, and some other periodic tasks and other running programs (X11, your IDE, a music player, and other random things) are competing for the CPU a little.

To get up to a load average of 9, something else must be going on.