Devel and XHProf configuration! I have installed Devel and XHprof to profile (kind of performance analysis) my website . Configured everything but i am confused with this setting 


  XHProf URL: Path to the publically accessible xhprof_html - required to display profiler reports. You will need to set this up
  outside Drupal, for example at http://xhprof.localhost/xhprof_html


my drupal installation is in inside /www/ 
please help
You need to set up a virtual host on your server and put the xhprof front-end HTML files on it (the ones that come with the the xhprof download). Give the host an address (e.g. http://xhprof.localhost/xhprof_html as suggested), then give that path to Devel. 

Then you should get the link at the bottom of each page to check the profiling information for that request.