Factors affecting processor's performance Flashcards
What are the 3 main factor affecting the processor’s performance
number of cores
the amount and type of cache
the clock speed
Each CPU operations start as the clock switch from…
0 to 1
The CPU cannot perform operations faster than the..
the time a clock cycle takes to complete
A clock cycle is the time it takes to switch…
from 0 to 1 and back to 0
One clock cycle per second
1Hz
What’s the reason behind having one or multiple unsued cores when an instruction being executed
Some softwares may not be able to take the full advantage of both or multiple processors
Define cache
a small amount of very expensive and very fast memory inside the CPU that stores recent instructions so that the CPU can acess them from them as it is quicker if needed be. As cache fills up, unused data or instructions are replaced with more recent ones.
What does pipelining allows a CPU to do
To do multiple steps of the FDE cycle simultaneously.
What does pipelining improves ?
performance of the processor
Processor pipelining can be divided into..
an arithmetic pipeline
and an instruction pipeline
The arithmetic pipeline represents the parts of an arithmetic operations that can be..
broken down and overlapped as they are performed
The instruction pipeline consistis of the stages in..
which an instruction is moved through the processor
Levels of cache
LEVEL 1 CACHE: 2-64KB, very fast with small capacity
LEVEL 2 CACHE: 256KB - 2MB, realtively fats and medium size capacity
LEVEL 3 CACHE: much larger and slower
Describe the Von Neumann Architecture
This architecture includes the basic components of the computer and processor (single CU, ALU, registers and memory units) in which a shared memory and shared data bus is used for both data and instructions.
Von Neumann architecture is built on the stored program concept.
Describe the Harvard architecture
Harvard architecture has physically separate memories for instructions and data, more commonly used with embedded processors. This is useful for when memories have different characteristics, i.e. instructions may be read only, while data may be read-write.
This also allows you to optimise the size of individual memory cells and their buses depending on your needs, i.e. the instruction memory can be designed to be larger so a larger word size can be used for instructions.
Describe the Harvard architecture
Harvard architecture has physically separate memories for instructions and data, more commonly used with embedded processors. This is useful for when memories have different characteristics, i.e. instructions may be read only, while data may be read-write.
This also allows you to optimise the size of individual memory cells and their buses depending on your needs, i.e. the instruction memory can be designed to be larger so a larger word size can be used for instructions.
Pros of using Von Neumann architecture
Programs can be optimised in size,
and it is cheaper to developed as the CU is easier to design
Pros of using Havard architecture
Quicker execution time as data and instructions can be fetched in parallel,
and memories can be different sizes, which can make more efficient use of space
Talk about Contemporary processors
Contemporary processors use a combination of Harvard and Von Neumann architecture.
Von Neumann is used when working with data and instructions in main memory, but uses
Harvard architecture to divide the cache into instruction cache and data cache
