Table of contents
2. Eight great ideas of computer system architecture
2. Abstraction and simplification
3. Accelerate high-probability events
4. Abstraction – simplifying the design
8. Number of instructions and CPI
10.1 Improvement (needs analysis)
10.2 Power Consumption and Utilization
Series Article Directory
This series of blogs focuses on the core content of the computer system (3) course of Shenzhen University, and the bibliography "Computer Composition and Design" (if you have any questions, please discuss and point out in the comment area, or contact me directly by private message).
Chapter 1 Computer Composition and Design 01 - Computer Overview and Technology
synopsis
This blog mainly introduces the core content of the computer composition and design book, as well as the relevant knowledge of computer overview and technology in the first chapter of the bibliography.
1. Content of this course
2. Eight great ideas of computer system architecture
1. Moore's Law
Tip: When designing, consider the situation of the integrated circuit in the future (when it goes on the market)
2. Abstraction and simplification
3. Accelerate high-probability events
Core: If the code is used iteratively, it is necessary to optimize the high probability event (important program)
4. Abstraction – simplifying the design
5.API vs. ABI
6. Manufacturing of ICs
The purpose of multiple tests after patterning and dicing: to improve the area utilization of blank wafers
7. Computer efficiency
The efficiency of a computer is related to response time and throughput .
Response time (execution time): The total time a computer takes to complete a task
Throughput rate (bandwidth): the number of tasks completed per unit of time
For example, number of tasks / number of transactions /... per hour
How to positively affect response time and throughput
1. Replace the processor with a higher speed model
2. Add multiple processors to handle independent tasks separately
Tips: We focus on response time...
Total response time includes everything (CPU time too): processing , I/O operations , OS overhead , idle time
Clock cycle time = 1/clock frequency
Clock cycle: The time of one clock cycle of the computer eg, 250ps = 0.25ns = 250×10–12s
Clock frequency: number of clock cycles per second eg, 4.0GHz = 4000MHz = 4.0×109Hz
A sample is as follows:
8. Number of instructions and CPI
8.1 CPI
CPI (Clock cycle per instruction): The average number of clock cycles required for each instruction
Tips: The number of instructions for a program depends on the program, ISA and compiler
Average clock cycles per instruction (CPI)
Determined by CPU hardware
If different instructions have different CPI , then the average CPI is affected by the entire instruction set
Tips: According to the CPU time ratio, the ratio of execution time (efficiency) can be derived
8.2 Complex CPI
If an instruction sequence has n different types of instructions, each requiring a different number of clock cycles (corresponding to the definition of CPI), then
A sample is as follows:
8.3 Performance Metrics
Examples are as follows (n-core is not n-fold higher than single-core, and there are losses):
9. Power Consumption Trend
The power consumption per transistor based on CMOS integrated circuit technology is as follows:
Tips: Power consumption is proportional to capacitance, voltage, and switching frequency (you can’t reduce the formula infinitely)
10. Some pitfalls
10.1 Improvement (needs analysis)
Example : A program takes 100 seconds to run, and the multiplication operation takes 80 seconds
How much should the speed of the multiplication be improved if the program runs 5 times faster ?
10.2 Power Consumption and Utilization
Fallacy : Low Utilization Computers Use Low Power
10.3 MIPS
MIPS is a supercomputer with millions of instructions per second. It cannot be used as a single performance indicator because it cannot explain the differences in the instruction sets between computers and the differences in the complexity of instructions.
Summarize
The above is the summary of the core content of the book and the first chapter - the core knowledge of computer overview and technology. In the first chapter, it mainly focuses on the introduction of 8 design ideas in the computer system structure , computer efficiency and power consumption .