Computer Systems and Performance Flashcards
Key goal of computer designers
Good performance in the sense of ______
execution speed
The benefit of increasing speed
Not to do some things faster, but that new applications become possible
Increases in processor speed have been achieved by
improvements in implementation technology(VLSI) and development of clever processor organizations and architecture
reducing power consumption
reduce power consumption in order to
avoid overheating of chips with many transistors
proliferation of battery powered devices
energy cost in datacenters
climate change
to understand computer organization/architecture
we need to understand what the hardware actually does (machine language executed)
assembly language is a ________ ________ of machine language
symbolic/textual representation
A Processor consists of
the datapath
the control
the datapath
carries out the operations specified in the machine language instructions being executed
the control
tells the datapath (and memory and I/O devices) what to do
in reality, the execution of each instruction is ________
the goal is to ______
typically overlapped with the executions of other instructions
increase execution speed, and maintain the same outcome as if execution was strictly sequential
memory
processor caching
and virtual memory
memory hierarchy managed so as to achieve
high speed and high capacity
Why I should know assembly language
- know about how computers work
- important when programming systems software
- important when application performance needs to be optimized (exploit parralellism and/or caching)
CPU execution time as a product of 3 factors
instruction count
clock cycle time
CPI
Instruction count
of machine language instructions executed
Instruction count depends on
high level language program
Instruction set program
compiler
processors rely on ______ to time their operations
clock cycle time
the clock cycle time is
the time between clock ticks
each step of instruction execution requires
one clock cycle
clock cycle time is commonly measuredn
nano seconds or pico seconds
cct depends on
architecture implementation
may need to derive cct from ______ using ____
clock rate
cct = 1/clock rate
clock rate is commonly measured in
GHz (billions of cycles per second)
processors can dynamically vary their clock rate to ___
for such processors it is the _______ that is a factor in the CPU execution time
achieve some desired trade off between power usage and performance
average clock cycle time when running a program