Clock synchronization of multiprocessor systems
OwnerJacob Katzenelson, Doron Moshe Erezinventors
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Abstract
A method of synchronizing a general network of processors, which network may contain loops, the method comprising: (a) providing clock signals at each of the processors, said clock signals having a common frequency; (b) measuring the phase between clock signals of different processors at the processors; and (c) adjusting the phase of the clock signals to produce local clock signals at each processor by varying the phases of the clock signals of individual ones of the processors, responsive to the measurements, such that phase differences between the clock signals of adjacent processors are less than a predetermined value δ, wherein such adjustment is controlled by at least one computer.
Claims23
A method of synchronizing a general network of processors, which network may contain loops, the method comprising:
- (a) providing a clock signal at each of the processors, said clock signal having a common frequency and different phases;
- (b) measuring the phase between clock signals of adjacent processors at the processors;
- (c) adjusting the phase of the clock signals to produce local clock signals at each processor by locally varying the phases of the individual clock signals, responsive to the measurement, such that phase differences between the clock signals of adjacent processors are less than a predetermined amount.
A method of eliminating phase cycle in a loop connected system, the network comprising processors having a clock with at least a variable phase, the method comprising:
- (i) choosing a spanning tree of the network, arranged in hierarchical levels;
- (ii) adjusting the phase of the clock signals in a first descendent level of the processors to be different from the clock of a root processor of the network by less than a given amount, in a first time sense;
- (iii) adjusting the phase of the clocks in a second descendant level of the processors to be different from the clock of their immediate ancestor by less than the given amount in a second time sense opposite from the first time sense;
- (iv) repeating (ii) and (iii) for succeeding descendant levels of the processors until the end of the tree is reached.
A method of synchronizing a general network of processors, which network may contain loops, the method comprising:
- (a) providing clock signals at each of the processors, said clock signals having a common frequency;
- (b) measuring the phase between clock signals of different processors at the processors;
- and
- (c) adjusting the phase of the clock signals to produce local clock signals at each processor by varying the phases of the clock signals of individual ones of the processors, responsive to the measurements, such that phase differences between the clock signals of adjacent processors are less than a predetermined value 6, wherein such adjustment is controlled by at least one computer.
Dependencies are inferred from the claim text.