Is there any open source tool for flash performance testing.
You don't 'load test' Flash, you profile it. So danii's Answer is relevant in the context of your original question. Your later comment, however, suggests that you actually want to load test an application that happens to use Flash on the client. Very different situation and the answer there is simply to not load test Flash itself but to isolate your efforts to the HTTP traffic. A good open source tool that you can use to achieve this is Apache JMeter.