RU1837289C - Two-input priority unit - Google Patents

Abstract

The invention relates to the field of computer technology and can be used to control access to a shared resource of two active devices of a computer system. The purpose of the invention is to expand the scope by implementing a circular discipline of request servicing, which allows priority to be given to shorter requests when the duration of request servicing is not known in advance. Achieving the goal is ensured by introducing into the two-input device a priority of new connections between the elements, which allows to increase the number of served requests during the life of the shared resource by quantizing the time of serving the requests. 1 ill.

Description

The invention relates to the field of computer technology and can be used to control access to the general

p €

the course of two active devices of a computing system.

The purpose of the invention is to expand the scope of the device by implementing a logical service discipline, which makes it possible to give priority to shorter requests when the duration of the service is not known in advance;

The drawing shows the functional diagram of the device.

The device contains an ibcoa 1-type generator. Elements I 2-5. comparison circuit 6, register 7, trigger 8, element OR 9, counts from 10, element NOT 11, element NAND 12, inputs 13, 14, group of code inputs 15,

you

: odes 16, 17.

The elements of the device shown in the drawing are connected as follows. The first input 13 of the device is connected to the first inputs of the first element And 21 and the element AND-NOT 12, the second input of which is connected to the second input 14 of the device and the first input of the second element And 3, the output of which is connected to the second output 17 of the device, the output of the first element And 2 connected to the first output 16 of the device, the output of the pulse generator 1 is connected to the first inputs of /, the third element And 4 and the fourth element And 5, the output of which is connected to the counting input of the counter 10, the group of outputs of which is connected to the second group of inputs of the comparison circuit 6, the first group of inputs of which is connected to the group of outputs of register 7, the group of inputs of which is the group of code inputs 15 of the device, the output of the comparison circuit 6

oo with x |

ke

00

about

connected to the input of zeroing the counter 10 and the third input of the AND-NOT 12 element, the output of which is connected to the third inputs of the second AND 3 element and the first AND 2 element, the second input of the fourth AND 5 element is connected to the input of the HE 11 element, the output of which is connected to the second input the third element And 4, the output of which is connected to the counting input of the trigger 8, the unit and bullet outputs of which are connected with the second inputs respectively of the first element And 2 of the second element And 3. the second input of the element OR 9 is connected to the output of the first element And 2 and the input Settings in the latch unit 8, a zero setting input of which is connected with the output of the second AND gate 3 and the first input of the OR gate 9, whose output is connected to the input of NOT 11.

The device operates as follows.

In the initial state, the counter 10 is in the zero state, a code for the value of the quantum of the service time is set on register 7, zero signals are set on the inputs 13, 14. The trigger 8 switches from one state to another as pulses arrive from the generator 1 through the And element 4. At random times, the device inputs 13 and 14 receive service requests (single signals). The request is present at the appropriate entrance until the end of its full service.

Consider the operation of the device in the most ACCIDENT situation when requests for input 13 and input 14 are simultaneously received. Suppose that trigger 8 was in a single state at the time of the receipt of requests. In this case, the service will receive a request received at input 13, because the And 2 element will turn out to be a single signal open at the third input from the output of the And-NOT 12 element (since at its third input there is a zero signal from the output of the comparison circuit 6), and at the second input, a single signal from the single output of trigger 8. Thus , at the output 16 of the device, a single signal from the output of the And 2 element will be established. The same signal, arriving at the input of the installation in the single state of trigger 8, will ensure that the trigger is held in the single state, and through the OR 9 and NOT 11 elements it will close the And 4 element by the second entrance, thereby stopping the flow of them a pulse generator 1 to the count input of the flip-flop 8.

From the moment of the appearance of a single signal at the output 16, service begins with the common request resource,

received at the input 13, and the time of its continuous service will be taken into account at the counter 10, since a single signal from the output of the element OR 9 will open on the first

input element 5, through the first input of which counting pulses from generator 1 will begin to arrive at the counting input of counter 10. After a code equal to the code recorded on the group of outputs of counter 10

in register 7, from the output of the comparison circuit 6, a single signal (the duration of which will be indicated below) will reset the counter 10 and will go to the third input of the AND-NOT 12 element, and so on. its other two inputs already have

5 single signals, at the output of this element, there is a zero signal, which closes the And 2 and And 3 elements at the third inputs, ensuring the input of zero signals from their outputs to the installation inputs of trigger 8 and closing through the OR element 9 at the second input of And 5 so that the counting pulses do not arrive at the counter 10, and the And 4 element opens with a single signal from the output of the HE 11 element, and with the next pulse 5 s from the generator 1, the trigger 8 switches to the zero state. At this point, the single signal from the output of the comparison circuit 6 will end (its duration is calculated as the sum of the response times of the elements 12, 2, 9, 11, 4 and the pulse repetition period of the generator 1) and a single signal will appear at the output of the AND-NOT 12 element. which will lead to the operation of the element And 3, because the trigger is now at zero state. Further, the operation of the device is carried out similarly to the above and, thus, provides the allocation of a quantum of time service to the request received at input 14. If during

0 of the next quantum, the service of one of the requests is completely over, i.e. at the corresponding input 13 or 14 a zero signal is received, the device will go on to service another request, and if there is only one request in the service queue (there is a single signal on only one of the inputs), then the service is not interrupted another time slice is allocated.

0 Thus, the proposed device implements a cyclical discipline of servicing requests, providing priority to requests with a short duration of service with an a priori uncertainty in the time required to service these requests. Such query servicing leads to maximization (with the correct choice of the quantum value) of the number of queries serviced by a common resource (PR) during its operation.

| Due to the fact that the proposed device does not create savings, but gives a different positive effect - it allows to increase the number of requests served by the general resource, we will conduct a comparative analysis of the proposed and basic device, in which a two-input priority device is selected (1), since it is more It effectively implements the functions of servicing and requests with previously unknown: required service durations.

Let us analyze the number of serviced -1 requests in a computer system containing two subscribers and a common resource - for example, a processor for a time interval of -1I, equal to 6 arbitrary units. I Suppose that at the beginning of the analyzed interval two requests arrived simultaneously; the first from the first subscriber, requiring 8 units of service time, and the second from the second subscriber, requiring 2 units of service time.

When using the basic devices in a computing system with a probability of 0.5, one janpoc (from the second subscriber) will be fully served for the analyzed femeni interval, and with a probability of 0.5, not a single request, i.e. considers an average of 0.5 requests,

; When using the proposed service, assuming that the service quantum is equal to one unit of time and the cost of interrupting the PR from serving one subscriber to serving another subscriber can be neglected completely. With a probability of 1, one request will be served (from one subscriber).

I Thus, the relative gain in the number of served requests when using the proposed device compared to the base will be 100 (1-0.5) -50%.

i FORMULA AND Sample | Two-input priority device, containing a pulse generator, first,

the second, third, fourth AND element, the comparison circuit, register, trigger, OR element, counter and AND element, the first request input of the device connected to the first inputs of the first AND element and the AND element, the second input of the device is connected to the first input of the second element And, the output of the pulse generator is connected to the first inputs of the third and fourth elements And,

the output of which is connected to the counter input of the counter, the first group of inputs of the comparison circuit is connected to the group of outputs of the register, the group of information inputs of which is a group of code inputs

device, the inverse trigger output is connected to the second input of the second AND element, the output of which is connected to the first input of the OR element, the output of which is connected to the input of the element NOT, different

the fact that, in order to expand the scope by implementing a circular discipline of request servicing, which allows priority to be given to shorter requests when the duration of request servicing is not known in advance, the second request input of the device is connected to the second input of the NAND element , the output of the third AND element is connected to the counting input of the trigger, the single output of which is connected to the second input of the first element, the second input of the OR element is connected to the output of the first And element and the installation input 1 trigger, and is the first output of the apparatus,

the input of the installation in trigger O is connected to the output of the second AND element and is the second output of the device, the output of the AND gate is connected to the third inputs of the first and second AND elements, the third input of the AND gate is connected to the output of the comparison circuit and to the counter reset input, the group of outputs of which is connected to the second group of inputs of the comparison circuit, the output of the OR element is connected to the second input of the fourth

element AND, the output of the element is NOT connected to the second input of the third element I.