Apparatus and computer program product for TOD-clock steering
AssigneeInternational Business Machines Corporation
InventorsEberhard Engler, Mark S. Farrell, Klaus Meissner, Ronald M. Smith, Sr.
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Abstract
A system, method and computer program product for steering a time-of-day (TOD) clock for a computer system having a physical clock providing a time base for executing operations that is stepped to a common oscillator. The method includes computing a TOD-clock offset value (d) to be added to a physical-clock value (Tr) value to obtain a logical TOD-clock value (Tb), where the logical TOD-clock value is adjustable without adjusting a stepping rate of the oscillator.
Claims18
A time of day (TOD)-clock steering apparatus for a computer system having a physical clock providing a time base for executing operations that is stepping to a common oscillator, said apparatus comprising:
- a memory storage device;
- a processor in communications with the memory storage device, wherein the apparatus is configured to perform a method comprising:
- computing a TOD-clock offset value (d) to be added to a physical clock value (Tr) to obtain a logical TOD clock value (Tb), said logical TOD clock value being adjustable without adjusting a stepping rate of said oscillator,
- wherein said TOD-clock offset value (d) is computed according to:
- d=b+(Tr−s)×r
- where (b) is a base offset value aligned wit bits of (Tr), (s) is a current start time value aligned with bits of (Tr), and, (r) is a current steering rate value, said s, b and r values defining a TOD-clock steering adjustment value.
A computer program product for steering a time of day (TOD)-clock for a computer system having a physical clock providing a time base for executing operations that is stepping to a common oscillator, the computer program product comprising:
- a storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising:
- computing a TOD-clock offset value (d) to be added to a physical clock value (Tr) to obtain a logical TOD clock value (Tb), said logical TOD clock value being adjustable without adjusting a stepping rate of said oscillator,
- wherein said TOD-clock offset value (d) is computed according to:
- d=b+(Tr−s)×r
- where (b) is a base offset value aligned with bits of (Tr), (s) is a current start time value aligned with bits of (Tr), and, (r) is a current steering rate value, said s, b and r values defining a TOD-clock steering adjustment value.
Dependencies are inferred from the claim text.