Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A: Instruction pipelining improves CPU throughput. Reason R: Pipelining decreases the execution time of each individual instruction. In the light of the above statements, choose the most appropriate answer from the options given below
Assertion A Analysis: Instruction Pipelining Improves CPU Throughput
Instruction pipelining is a technique used in CPU design to improve performance by overlapping the execution stages of multiple instructions. Different stages of instruction processing (like Fetch, Decode, Execute, Writeback) are handled by different hardware units simultaneously.
- Benefit: This overlap allows the CPU to work on multiple instructions concurrently, completing more instructions in a given period.
- Throughput: CPU throughput is defined as the number of instructions completed per unit of time. Pipelining directly increases this measure.
- Conclusion: Therefore, Assertion A is correct. Instruction pipelining effectively improves CPU throughput.
Reason R Analysis: Pipelining Decreases Individual Instruction Execution Time
While pipelining enhances overall throughput, it doesn't necessarily decrease the execution time (latency) of a single, individual instruction.
- Latency: The total time taken for one instruction to complete its entire execution from start to finish is its latency.
- Pipeline Effect: Pipelining breaks execution into stages. An instruction still needs to pass through all these stages sequentially. The total latency for a single instruction might remain similar or even slightly increase due to pipeline overheads (e.g., clock cycle requirements for each stage, register delays between stages).
- Throughput vs. Latency: The primary goal and benefit of pipelining is increased throughput, not reduced latency for individual instructions.
- Conclusion: Reason R is incorrect because pipelining does not guarantee a decrease in the execution time of each individual instruction; it focuses on increasing the rate of instruction completion.
Final Conclusion
Based on the analysis, Assertion A is correct, but Reason R is not correct. Pipelining improves the overall rate of instruction processing (throughput) but not necessarily the time it takes for a single instruction to complete (latency).
Therefore, the most appropriate choice is that A is correct but R is not correct.
Important Questions from Data-Path and Control Unit
Given below are two statements:
Statement I: Hardwired control unit can be optimized to produce fast mode of operation.
Statement II: Indirect addressing mode needs two memory reference to fetch the operand.
In the light of the above statements. choose the correct answer from the options given below
Which of the following statements with respect to multiprocessor system are true?
(A) Multiprocessor system is controlled by one operating system.
(B) In Multiprocessor system, multiple computers are connected by the means of communication lines.
(C) Multiprocessor system is classified as multiple instruction stream and multiple data stream system.
Choose the correct answer from the options given below:
The following program is stored in memory unit of the basic computer. What is the content of the accumulator after the execution of program? (All location numbers listed below are in hexadecimal).
Location
Instruction
210
CLA
211
ADD 217
212
INC
213
STA 217
214
LDA 218
215
CMA
216
AND 217
217
1234H
218
9CE2H
A partial data path of a processor is given in the figure, where RA, RB, and RZ are 32-bit registers. Which option(s) is/are CORRECT related to arithmetic operations using the data path as shown?
