Method and apparatus for measurements of channel operation
First Claim
1. A channel measuring system comprising,a central processor having a time of day clock, a channel having a channel clock, means connecting a stage of the central processor time of day clock to increment the channel clock at intervals defining the resolution of the measuring system, and means connecting a stage of the central processor time of day clock to reset the channel clock at intervals corresponding to the longest channel operation to be monitored, whereby after an initial reset operation the channel clock is comparable with corresponding stages of the central processor time of day clock,means in the central processor for starting a channel operation including means for storing the value of the system time of day clock in a predetermined location,means in the channel for accessing the channel clock at a predetermined point in said channel operation, andmeans in the channel for subtracting the stored value of the central processor time of day clock and the channel clock and calculating the time interval from the time when the central processor starts the channel operation to the time when the channel reaches the predetermined points in its operation,whereby channel measurements operations are performed.
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Abstract
A channel for a data processing system is provided with a time of day clock that is synchronized with the time of day clock of the associated central processor. Both the central processor and the channel processor record times of particular events, and the channel uses these times to calculate two times called Function Pending and Function Active. Both times begin when the central processor executes an instruction to begin an I/O operation. Function Pending ends when the channel has made successful initial selection. This time shows delays by the channel processor in scheduling the channel control unit, and device resources for I/O operations. Function Active ends at Channel End. A new instruction, Set Channel Monitor, enables or disables these measurements. An information block for each subchannel defines one of several measurement modes for a subchannel or disables the subchannel from measurement.
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Citations
11 Claims
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1. A channel measuring system comprising,
a central processor having a time of day clock, a channel having a channel clock, means connecting a stage of the central processor time of day clock to increment the channel clock at intervals defining the resolution of the measuring system, and means connecting a stage of the central processor time of day clock to reset the channel clock at intervals corresponding to the longest channel operation to be monitored, whereby after an initial reset operation the channel clock is comparable with corresponding stages of the central processor time of day clock, means in the central processor for starting a channel operation including means for storing the value of the system time of day clock in a predetermined location, means in the channel for accessing the channel clock at a predetermined point in said channel operation, and means in the channel for subtracting the stored value of the central processor time of day clock and the channel clock and calculating the time interval from the time when the central processor starts the channel operation to the time when the channel reaches the predetermined points in its operation, whereby channel measurements operations are performed.
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11. A method for measuring parameters of subchannel operations, comprising,
recording the time of execution of a central processor instruction to start a subchannel operation (Start Subchannel), determining the time of acceptance of the first channel command by the device associated with the subchannel (Successful Initial Selection), determining the time of the completion of the channel operation (Channel End), operating on the times to produce a first time (Function Pending) that indicates the delays by the channel in obtaining resources for the subchannel operation and to calculate a second time (Function Active) that indicates the total time of the subchannel operation.
Specification