title: Why increasing number of threads is useless?
body: <p>I've been looking for the way to increase the speed of processing messages received from rabbitmq queue. The only way I've found is make more than one threads doing the same - receiving and processing. And this gave me some profit. After I created 4 threads the speed quadrupled. As I have 8-core processor I've decided to increase the number of threads to 8. But this gives no performance increasing. YourKit shows that only 50% of CPU is used. Somebody can say that my app is lightweight and so it is so, but I can say that it can't do more work than it does regardless I produce much more what to do. Why this doesn't work?</p>