SU1661785A1 - Queueing system simulator - Google Patents

Abstract

The invention relates to specialized computer facilities and is intended to simulate the processes of servicing two flows of a different priority order with one serving device. The purpose of the invention is to enhance the functionality by simulating a scheduling delay when interrupting service of a low priority application. The device contains high and low priority inputs, five AND elements, two triggers, an inhibit element, five isolation diodes, two pulse generators with a random following interval, a count of service repetitions, a delay element. 1 il.

Description

The invention relates to specialized computer facilities and is intended to simulate the process of servicing two flows of applications with different priorities by one device.

The purpose of the invention is to enhance the functionality by simulating a scheduling delay when interrupting service of a low priority application.

The drawing shows a diagram of the device.

The device contains inputs for high 1 and low 2 priorities, first 3 and third 4 elements And, first 5 and second 6 triggers, prohibition element 7, first isolation diode 8, second element And 9, first 10 and second 11 pulse generators with random following interval, the counter 12 is the number of repetitions of service, the fifth 13, the second 14, the fourth 15 and the third 16 dividing diodes, the fourth 17 and the fifth 18 And elements, the delay element 19.

The verbal model of the device is the following.

Two random flows for servicing go to one serving device. Applications for service with a lower priority are accepted if there is no demand with a higher priority. For requests of the same priority, received at the moment when the servicing device is busy, the service is denied. If a high priority application is received during the service period of a lower priority application, then a lower priority application service is terminated, and a higher priority application is served. After the service device is released, the service previously received for service with a lower priority is resumed. However, after a fixed number of interrupts, a low priority application (L

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secondly, service is not accepted and is lost.

The service request flows at inputs 1 and 2 represent a random pulse sequence, the intervals between which are distributed according to certain (different or the same) laws.

The model of the servicing device are the generators 10 and 11. The law of distribution of random pulses at the outputs of the generators 10 and 11 is the same, since they simulate the same device.

Counter 12 counts the number of times the low priority service has been interrupted by a high priority. As soon as the number of repetitions reaches the set value, a pulse is produced at its output.

The delay element 19 in interrupting service of a low priority application of a high priority application takes into account the scheduling time of the application, which is as follows: interruption to terminate the execution of the service of the low priority application: remembering the state of the service of the low priority application: providing resources for servicing the application high priority.

The device can operate in three modes: servicing a high priority charge, servicing a low priority charge, and servicing a higher priority charge received at the time of servicing a lower priority charge.

The device works as follows.

In the initial state, in all modes, the triggers 5 and 6 are set to the position where the outputs connected to the And 3 and 4 elements have a high potential. At the same time, there is no voltage at the control input of prohibition element 7. This item is open.

Service for low priority wok. The pulses from the input 2 through the elements 4 and 7 and the diode 8 start the generator 11, and the trigger 6 is switched to the position in which the elements 4 and 17 are closed until the end of the application service. Element 18 is open to receive a high priority application. Entries received from input 2 at the same time are not accepted for service and are lost. After the end of the service, the impulse from the output of the generator 11 through the diode 16 moves the trigger 6 to the position at which the elements 4 and 17 are opened and the element 18 closes.

Service for high priority wok. The impulse from input 1 through the open elements And 3 and 17 starts the generator 10 and transfers the trigger 5 to a state in which a high potential is removed from the element 3 and the voltage applied to

control (prohibiting) the input element 7 of the ban. In this case, applications received from input 1 are lost, since AND 3 is closed, and applications from input 2, which passed through AND 4, are not accepted for service, because element 7 is closed. After the termination of the service of the application and the occurrence of a pulse at the output of the generator 10, the scheme is reset to the initial state - the elements of AND 3 and prohibition 7 are opened.

5 Servicing high priority charges received during the servicing period of a low priority tender. For low priority from input 2 through open element 7, the generator 11 starts and tilts trigger 6, and elements 4 and 17 are closed, and a second potential is fed to the second input of element 9 9 from output of trigger 6 and the element 18 opens.

5 The application of the highest priority from input 2 to the end of generator 11 operation through open elements 3 and 18 enters delay element 19, taking into account the scheduling time of the serving device, starts generator 10, sets generator 11 to its initial state (which simulates a service interruption low priority) and flips trigger 5. This closes the AND element

5 3 and item 7 is closed. In such a state, the scheme is held until the end of service of a high priority application. After the appearance of a pulse at the output of the generator 10, trigger 5 is tilted,

0 opening elements 3 and 7. At the same time, the same impulse passes through elements 9 and 18, at the second inputs of which there is a resolving potential from trigger b, to start the generator 11. Thus, repeated maintenance of applications with lower priority is simulated. In addition, the same pulse is fed to the counting input of the counter 12.

Prior to the end of service trigger 6

0 keeps the elements AND 4 and 17 in the closed state, and the elements AND 9 and 18 in the open state. If the low priority application has time to be served before the appearance of the high priority, then after the appearance of a pulse at the top of the generator circuit 11, the circuit returns to its initial state; a pulse from the output of the generator 11 through the diode 16 is fed to the input of the trigger 6 and the reset input of the counter 12. As a result, the elements 4 and 17 open at the second input.

Let the low-priority application not have time to be re-served (its service will be interrupted by the newly received input 1 of the high-priority application). The impulse from input 1 through the open element I 3 sets the generator 11 to the initial state. Element 3 is closed at the second entrance until the end of the high priority service.

After the end of the service of high priority application at the generator output

10po is a pulse (imitating the end of service applications). This pulse arrives at the input of the trigger 5. As a result, the element And 3 opens at the second input. Simultaneously, the same pulse through the open element And 9 is fed to the counting input of the counter 12. In addition, through the diode 13, this pulse is fed to the input of the generator

11 and launches it (simulates the next re-maintenance of previously interrupted low-priority applications). Such repetitions may be K, therefore, K times it is necessary to take into account the time for dispatching. As soon as the next impulse arrives at the counting input of the counter 12, the total number of which reaches K, the output of the overflow results in a pulse, which through the diode 15 sets the generator 11 to its initial position, and also sets the elements 4 and 17, trigger 6, counter 12 initial state.

Claims (1)

The invention The device for simulating a queuing system that contains the first And element, the first input of which is the input of the high priority device, the second input of the first And element is connected to the inverse output of the first trigger, and the output of the first And element is connected to the zero input of the first trigger, the first pulse generator with a random interval, the output of which is the output of the served high priority device devices and is connected to the first input of the second element AND and the unit the primary input of the first trigger, the direct output of which is connected to the control input of the prohibition element, the information input of which is connected to the output of the third element AND, the first input of which is an input of the low priority device, and the second input of the third element And is connected to the inverse output of the second trigger, the direct output of which is connected to the second input of the second element And, the output of the inhibit element is connected to the single input of the second trigger directly, and to the trigger input of the second pulse generator with a random interval following through the first separation diode, the output of the second pulse generator with a random interval following is the output of the low priority device outputs, the output of the first And element through the second isolation diode is connected to the stop input of the second pulse generator with a random following interval, the output of which through the third splitter The second diode is connected to the zero input of the second flip-flop and the reset input of the service repetition counter, the overflow output of which is connected to the zero input of the second flip-flop directly, and to the stop input of the second pulse generator with a random interval, through the fourth split diode, the output of the second element And through n The splitter diode is connected to the start input of the second pulse generator with a random following interval, and the counting input of the service repetition counter is connected to the output a second AND gate, the inputs The discharge repetition number counter service are input specifying the number of repetitions of the service device, characterized in that, in order to expand functionality of the device due to the scheduling delay simulation at the interrupt service applications of low priority, it additionally contains a delay element, the fourth and fifth elements And, the output of the first element And is connected to the first inputs of the fourth and fifth elements And, the second the inputs of which are connected respectively to the inverse and direct outputs of the second trigger, the output of the fifth element And is connected to the input of the delay element, the output of which and the output of the fourth element And via mounting OR are connected to the starting pulse of the first pulse generator with a random interval. -