Patent ID: 7865760

Claim:
A method of calculating clock offset and skew in a computer system, the method comprising the steps of: sending data packets from a first processing unit in the computer system to a second processing unit in the computer system; sending the data packets from the second processing unit to the first processing unit; providing first time stamps to indicate when the packets leave the first processing unit; providing second time stamps to indicate when the packets arrive at the second processing unit; providing third time stamps to indicate when the packets leave the second processing unit; providing fourth time stamps to indicate when the packets arrive at the first processing unit; defining a set of backward delay points using the fourth time stamps, each of said backward delay points representing a point on a graph defined, on a first axis, by a respective one fourth time stamp, and on a second axis, by a backward delay value determined using said respective one fourth time stamp; calculating a clock offset between clocks on the first and second processing units and a skew of said clocks using said set of backward delay points.