Patent ID: 7395448

Claim:
A method of facilitating a determination of the quality of time produced by clocks of processing environments, said method comprising: providing, by a clock of a central processor of the processing environment, a current time value and continuously updating by hardware of the processing environment the current time value, the processing environment comprising a supervisor service processing layer and an application program processing layer; and issuing a request, by an application program running within the application program processing layer of the processing environment, for information usable in determining the accuracy of the time value relative to an external time standard, the request being made via a perform timing facility function instruction, wherein execution of the perform timing facility function selects desired information and places the information in a parameter block specified by the application program, the parameter block being located in memory of the processing environment at an address specified in a general register by the perform timing facility function instruction, the parameter block being directly accessible by the application program, and wherein the information is obtained by the application program absent use of a supervisor service of the supervisor service processing layer.