Unit 1.1.1 (Continued): Processor Performance Flashcards
What are ‘words’?
They are units that comprise of memory divided equally.
How are instructions formatted, and what determines the formatting?
Instructions are formatted by machine code, as it shares a one-to-one correspondence with its assembly language equivalent.
The architecture of a computer, including:
. The ‘word’ size; and
. The width of the address bus
State and describe the main factors that affect a processor’s performance.
. Number of cores: the greater the number of cores increases performance (i.e. ‘n’ cores provides ‘n’ linked processors, for instance, making a quad-core computer two or even four times faster than a single-core computer).
. Clock speed: the faster the clock speed, the faster a computer can ‘fetch’, ‘decode’ and ‘execute’ instructions.
. Cache memory: The greater the cache, the less time taken for the processor to wait for instructions.
Describe the hierarchy of cache memory.
The hierarchy of cache memory is arranged such that:
- RAM –> Level 2 cache –> Level 1 cache –> CPU registers
Compare ‘Level 1’ and ‘Level 2’ cache.
‘Level 1’ cache memory is divided into instruction cache and data cache, so that data and instructions can be fetched simultaneously.
Whereas with ‘Level 2’ cache memory, it is larger, yet not as fast as ‘Level 1’ cache memory.
Both types are held on the processor chip.
What is pipelining, and refer this term to the FDE cycle?
It is a technique used to enhance performance, for instance, by overlapping stages in the FDE cycle, or by breaking down the stages in an arithmetic instruction.
What is parallel processing, and state an advantage and a disadvantage of this?
It is the use of several processor cores working simultaneously.
The benefit is that each core can work concurrently on different parts of the same task, thus decreasing the time taken for the task to be completed.
However, since instructions are processed sequentially, this is not always possible.
What is the system clock?
It is a series of regular ‘ON/OFF’ signals that are used to synchronise the operations of the processor components.
