Module 2: Components of CPU

Clock cycle

basic unit of time during which the processor performs operations; heartbeat of the processor

clock speed of CPU

measured in hertz, gigahertz for modern processors; each correponds to one oscillation of CPU’s internal clock

stages of CPU basic process of handling instructions

1. Fetch: retrieve instruction from memory

2. Decode: interpret instructions

3. Execute: perform operation

4. Memory access: if the instruction involves reading or writing data from memory, this happens

5. write back: CPU writes resulst of operation back to register file or memory

unit of measurement of clock cycle

hertz

CPU cores

modern have many cores; independent processing units capable of processing things in parallel; each one has its own thread(like task)

multi threaded applications

applications where multiple things have to be processed at the same time

CPU parts

control unit; ALU; registers

Control unit(CU)

directions operations in CPU; gets instructions from memory, decodes them, and then sends signals to other parts of the CPU (like the hypothalamus)

ALU

Performs arithmetic and logic operations; operates based on data stored in registers; produces results that can be sent to other part of CPU or written back to memory

Registers

Small, fast storage locations within the CPU that hold data temporarily during instruction execution; types: program counter(PC), accumulator, instruction register(IR), general purpose registers

Program counter(PC)

Holds address of next instruction to be executed

accumulator

holds immediate results of calculations

Instruction registers

holds the current instruction being executed

general purpose registers

used for storing data during computation

cpu components

cache memory

sit between CPU and main memory, very fast; helps reduce the time it takes to accomplish certain tasks

L1 cache memory

fastest and smallest; located closest to CPU cores

• sometimes integrated into the CPU core

• size: 16 KB to 128 KB per core

• purpose: stores most frequent instructions and data needed by CPU

• speed: fastest cache but limited storage capacity

L2 cache memory

larger and slowly, further from CPU

• sometimes shared amongst cores in CPU, other times each core has its own

• size: 128 KB to 4 MB per core, depending on CPU design

• purpose: store data that is frequently accessed as L1 cache data but still needs to be readily available

L3

even larger and even slower, but still faster than main memory

• generally shared across all cores in multi processor

• located on same chip as CPU

• size: 2 MB to 64 MB (or more) in modern processors

• Purpose: stores data that is less frequently used than L1 and L2

• speed: slowest of three cache levels but still significantly faster than accessing RAM

CPU example

intel core i9-13900K has:

• L1 cache: 32 KM per core(16 KB for data and 16 KB for instructions)

• L2 cache: 256 KB per core

• L3 cache: 36 mb shared across all cores

cache memory def

memory that allows for faster retrieval of information into the CPU, faster than through RAM/ROM

external cache

used before on-chip cache was common; L2 cache memory, could be physically separate from CPU and placed on separate; chip near the CPU; meant to store data between CPU and RAM; it was faster than accessing data from RAM but slower than the CPU’s internal cache

Buses

communication pathways that connect various components of CPU and the system, allowing data to be transferred between them (like synapses in the brain)

special types:

• data bus: transfers data

• address bus: carries memory addresses

• control bus: carries control signals to manage operations of the CPU and other components\

execution pipeline- piplelining

modern CPUS; breaks down instruction processing into multiple stages that can overlap, allowing multiple instructions to be processed simultaneously in different stages; helps the efficiency of the CPU

data processing pipeline

• data collection, cleaning, transformation, analysis, storage, and reporting

• example: in machine learning,d ata pipeline can be data extraction, preprocessing, feature engineering, model training, and evalulation

CI/CD pipeline (continuous integration/ continous deplyment)

• stages: commit code → code review—> build → test→ deploy

• example: developers push code changes to a repository, which triggers the pipeline for automated building, testing, and deployment

task execution pipline

• stages: job submission → task assignment→ execution → result collection

• example: in distributed computing, large tasks are broken down into smaller sub tasks executed in parallel or sequentially 

floating point unit

specialized part of CPU designed to handle calculations involving floating point numbers, scientific calculations, etc.; sometimes integrated into ALU, other times seperate component

execution units (EU)

modern CPUs can have multiple execution units to handle different tasks at the same time

clock

generates regular pulse (or signal) to synchronize operations of components in CPU

Bus Interface Unit (BIU)

existed in older systems; manages communication between CPU and external components like RAM; ensures data is fetched from and written to memory correctly; handless address and control signals

Thermal management

to manage heating and prevent overtemperature; may include thermal sensors too to monitor safe heat levels

integrated graphics

handles graphical tasks, like rendering images, videos, and 3D graphics; reduces the need for seperate graphics card in the system

CPU components diagram

Factors that influence performance of CPU

• architecture

• number of cores

• efficiency of instructions being executed

cpu cores

indepdent procesing units in CPU capable of executing instruction in parallel

CPU components

• control unit

  • arithmetic logic unit

Control unit

• responsible for directing operations of CPU

  • fetches instructions from memory, decodes them to determine what action to take, and then sends signals to other parts of the CPU to carry out the taskA

ALU

• performs arithmetic and logic operations

• includes basic operations, like addition and subtraction

Register

small, fast storage ocations within the CPU that hold data temporarily during the execution of instructions

Types of registers

• program counter

• accumulator

• instruction register

  • general purpose register

program counter

holds the address of the next instruction to be executed

accumulator

holds intermediate results of calculations

instruction register

holds the current instruction being executed

general purpose registers

used to store data during computation

Cache memory

memory between CPU and RAM; multiple levels - L1, L2, L3,

L1 cahce

fastest and smallest, typically closest to coreL

L2

bit larger and slightly slower

L3

slower but faster than RAM

bits vs processors

bits that the processor can support

8 bit processor

process 8 binary digits in a single operation, which is equal to one byte; uses 8 bits to represent integers, chars, and all other data types, so it can handle data values which are represented from 2^8 possible values in a single instruction; used in older or embedded systems; some microcontrollers and small embedded devices use it

16 bit processer

older systems, comon in embeded systems, gaming, consoles, workstations; very specific applications in modern; some very early computers and PCs

32 bit processor

embedded systems, older PCs

64 bit processors

standard for most modern computing, like desktops; can handle larger amounts of memory(more than 4GB), faster data processing, advanced operation systems and applications

128 bit processors

research but not in mainstream commercial devices

computer basic defonition

process to interpret or execute; memory to store data and programs; mechanism to transfer data to and from the outside world