computer organization CH1 Abstraction

1.1 intro

classes of computer

• Personal
• Embedded
• Server
• Supercomputers

why will you learned?

• the hardware/software interface

understanding performance I

• depends on effectiveness of tha algorithm
• the software systems used to create and translate the program into machine inst.

1.5 Technologies for building processors and memory

wafer of intel core processor

Integrated Circuit cost

• wafer cost and area are fixed

1.6 performance

performance goal

• response time
  • execute time
• Throughput (or bandwith)

relative performance

what is performance?

• performanc =

X is n time faster than Y

• =

Ex.

Elapsed time

• total response time
  • CPU, processing, I/O, OS overhead, idle time
• measured by clock time

CPU time

• only for cpu

CPU clock

• cpu has a constant clock that determines when events take place
  • the discrete time interval called clock cycle
• length of a clock period
  • time for a complete clock cycle
  • clock rate(frequency), inverse of the clock period
• hardware designer must often trade off clock rate against cycle count

Ex.

CPU time and Inst. count

• inst. count
  • determined by ISA
• cycles per instruction(CPI)
  • betermined by CPU hardware
  • diff. inst. have diff. CPI
  • average CPI affected by instruction mix

Ex.

more about performanc equation

• in particular, program would contain diff. classes of inst.(inst. mix)
• Equation
• Ex.

measuring computer performanc

• time is the only complete and relialbe measure

many factors

• algorithm
  • IC, CPI
• Programming
  • IC, CPI
• compiler
  • IC, CPI
• ISA
  • IC, CPI, clock rate

1.8 The Sea Change: The Switch to Multiprocessors

power limit

• how to reduce voltage and remove haet
  • power =
• force a dramatic change in the design of microprocessors

Switch from uni… to multiprocessors

• require explicitly parallel pregramming
• before is inst. level oarallelism

1.9 Real Stuff: Benchmarking the Intel Core i7

Benchmark a computer

• used to evaluate the performance of a new computer
  • the set of programs would form a workload
• SPEC
  • develop benchmark for cpu, I/O, web, etc
  • spec ratio =