title: best way to check performance of web application
body: <p>what is the best tool (open or commercial) currently available, that lets me send customized requests to a web server and get back a response to check the performance? </p>
  
  <p>i will be sending it a load of more than 20K per second, but i need to get numbers for each call made. also, the numbers might be in some microseconds or nanoseconds. How in this small measurement unit, can i work out a baseline and a benchmark?</p>