Originally developed at Facebook, XHProf was open sourced in Mar, 2009.

XHProf is now maintained by Phacility.

Creators:
  Changhao Jiang
  Kannan Muthukkaruppan
  Venkat Venkataramani
  Haiping Zhao

Additional Contributors:
  George Cabrera      - UI enhancements
  Paul Saab           - FreeBSD port
