Recap
(from Previous
Lecture)
1
Computer Architecture
• Computer Architecture involves 3 inter-
related components
– Instruction set architecture (ISA): The actual
programmer-visible instruction set and serves as the
boundary between the software and hardware.
– Organization: includes the high-level aspects of a
computer’s design such as: The memory system, the
bus structure, and the internal CPU unit.
– Hardware: Refers to the specifics of the machine
such as detailed logic design and packaging technology.
2
Computer Architecture
Technology
Programming
Languages
Applications
Computer Architecture:
• Instruction Set Design
• Organization
• Hardware
Operating
Systems History
Measurement &
Evaluation
Three Computing Markets Today
Desktop Server Embedded
4
Desktop Computer Systems
• For “General-Purpose” Use
– Word-Processing, Web surfing, Multimedia, etc.
– Computation and Programming
• What’s in the box
– Microprocessor
– Memory - DRAM
– Hard disk(s), CDROM/DVD, etc.
– I/O - mouse, keyboard, video card, monitor, network, etc.
• Important Issues:
– Optimized for price-performance
– Performance - how fast is “fast enough”?
– Cost
– Basic capabilities (and expandability) 5
Server Computer Systems
• Large-Scale Services
– File storage
– Computation (e.g., supercomputers)
– Transaction Processing, Web
• What’s in the Box(es)
– Microprocessor(s)
– Hard disks
– Network Interface(s)
• Important issues:
– Performance One Rack-Mount PC Unit
– Reliability, availability (Google uses ~ 10,000)
– Scalability
6
Embedded Computer Systems
• Computer as part of larger system
– Consumer electronics, appliances
– Networking, telecommunications
– Automotive / aircraft control
• What’s in the box
– Microcontroller / Microprocessor / System on Chip (SOC)
– Memory: RAM, ROM; Disk
– Special-purpose I/O (including analog stuff)
• Important issues
– Cost, Power Consumption
– Performance (against real-time constraints)
– Reliability and Safety
7
Trends in Computer Architectures
• Computer architectures has been advancing at
a very fast rate
• These advances can be attributed to advances
in technology as well as advances in computer
design
– Advances in technology (e.g., microelectronics, VLSI,
packaging, etc) have been fairly steady
– Advances in computer design (e.g., ISA, Cache,
RAID, ILP, etc.) have a much bigger impact (This is
the theme of this class).
8
Trends in Technology
• Trends in Technology followed closely Moore’s Law
“Transistor density of chips doubles every 1.5-2.0
years”
• As a consequence of Moore’s Law:
– Processor speed doubles every 1.5-2.0 years
– DRAM size doubles every 1.5-2.0 years
– Etc.
• These constitute a target that the computer
industry aim for.
9
Growth in processor performance
10000
From Hennessy and Patterson, Computer
Architecture: A Quantitative Approach, 4th
Performance (vs. VAX-11/780)
edition, October, 2006 20%/year
1000
52%/year
100
10
25%/year
1
1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006
• VAX : 25%/year 1978 to 1986
• RISC + x86: 52%/year 1986 to 2002
• RISC + x86: 20%/year 2002 to present 10
Integrated Circuits Capacity
11
Today: VLSI Microprocessors
Process Shrinks
Pentium® 4 Pentium® 4 “Northwood”
Pentium® 4 “Prescott”
42M transistors / 1.3-1.8GHz 55M transistors / 2-2.5GHz 125M transistors / 2.8-3.4GH
49-55W 55W 115W
L=180nm L=130nm Area=131mm 2
L=90nm Area=112mm2
12
Today: VLSI Microprocessors
Intel Itanium® 2 Intel Core 2 Duo
410M transistors / 1.3GHz / 130W 291M transistors / 2.67GHz / 65W
L=130nm Area=374mm2 L=65nm Area=143mm2
Image source: Intel Corporation www.intel.com
13
MOORE’s
LAW
Processor-DRAM Memory Gap (latency)
1000 CPU
µProc
60%/yr.
“Moore’s Law”
Performance
(2X/1.5yr)
100 Processor-Memory
Performance Gap:
(grows 50% / year)
10
DRAM
DRAM
9%/yr.
1 (2X/10 yrs)
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
14
We need a balanced Computer
System
Computer System
CPU
[Clock Period, Chain: As strong as its
CPI, Weakest ring
Instruction count]
Memory Bus [Bandwidth]
Memory Secondary
Storage
[Capacity, [Capacity,
Cycle Time] Data Rate]
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