| 摘要 |
A real-time scheduler for scheduling periodic access to a shared resource by a number of channels. The channel period for each channel is represented by a channel value partitioned into an extra-fine value, a fine value, and a coarse value. The fine value is in units of access intervals, the length of time of each access. The coarse value is in units of scheduling periods, the maximum number of access intervals that can be represented by the fine value. The extra-fine value is in units of a number that evenly divides the access interval. During each scheduling period all non-zero coarse values are decremented by one and then if zero, indicate that the next cell send time for that channel falls in the next scheduling period. Concurrently, a fine process executes repeatedly in which all fine values that had a zero coarse value at the end of the previous scheduling period are compared to find the smallest value. The scheduler waits until the smallest value is less than or equal to the current cell interval, and then outputs a trigger signal to initiate the sending of the next cell of the channel and to adjust the channel value using the channel period such that the extra-fine value overflows into the fine value.
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