computer architecture 101 - circuits systems
TRANSCRIPT
Who am I?
Who am I?
JRF in EEE
Why am I here?
Why am I here?
Ask questions…
Why am I here?
Monday/Thursday this week
This lecture organized as series of questions and answers…
Questions Roundup
• What is a computer architecture?
• How is a computer architecture implemented physically?
• Why is it relevant today/future?
• What is technology scaling?
• What does it mean for computer architecture?
What is computer architecture?
What is computer architecture?
Programmer – Abstraction - Machine
What is the first* example of one?
* commerical
Deutsches Museum, Munich http://www.flickr.com/photos/nachiketkapre/1393621052/
How is an architecture physically implemented?
“Matter computes”
André DeHon UPenn
André DeHon UPenn
“Matter computes”
Sand (Matter)
iPhone (Computer)
tomshardware.com
What is the job of a computer architect?
Carver Mead Caltech
“Tall, Thin Computer Architect”
Devices/Fabrication
Transistors/Wires
Gates/Circuits
Datapaths/Memories/Networks
Chips (CPUs, GPUs)
Firmware/Drivers/OS (Software)
Why is comp. arch. still relevant?
Why is comp. arch. still relevant?
end-of-silicon-scaling
http://en.wikipedia.org/wiki/Moore’s_law
What is it relevant today?
Heterogeneity/Specialization
Embedded Low-Power Systems
Desktops
Graphics, Scientific Computing
Why will it stay relevant?
Why will it stay relevant?
changing silicon costs
What is the impact of scaling?
What is the impact of scaling?
change how we organize computation
Transistor scaling
n drain n source
metal gate
p substrate
insulator
n drain n source
metal gate
p substrate
insulator
n drain n source
metal gate
p substrate
insulator
L
W Tox
n drain
p substrate
insulator
L/√2
metal gate
n source W/√2 Tox/√2
n drain
p substrate
insulator
L/√2
metal gate
n source W/√2 Tox/√2
Area? Delay? Power?
n drain
p substrate
insulator
L/√2
metal gate
n source W/√2 Tox/√2
Area? Delay? Power? Area ~ W*L
n drain
p substrate
insulator
L/√2
metal gate
n source W/√2 Tox/√2
Area=2x Delay? Power? Area ~ W*L
n drain
p substrate
insulator
L/√2
metal gate
n source W/√2 Tox/√2
Area=2x Delay? Power? τ = Q/I
n drain
p substrate
insulator
L/√2
metal gate
n source W/√2 Tox/√2
Area=2x Delay? Power? τ = CV/I
n drain
p substrate
insulator
L/√2
metal gate
n source W/√2 Tox/√2
Area=2x Delay? Power? C = ε*(W*L)/Tox
n drain
p substrate
insulator
L/√2
metal gate
n source W/√2 Tox/√2
Area=2x Delay=√2x Power? τ = CV/I
n drain
p substrate
insulator
L/√2
metal gate
n source W/√2 Tox/√2
Area=2x Delay=√2x Power? (Static) P=V*I
n drain
p substrate
insulator
L/√2
metal gate
n source W/√2 Tox/√2
Area=2x Delay=√2x Power? (Dynamic) P=½*f*C*V2
n drain
p substrate
insulator
L/√2
metal gate
n source W/√2 Tox/√2
Area=2x Delay=√2x Power=2x (Dynamic) P=½*f*C*V2
n drain
insulator
metal gate
n source
Width=√2 Length=√2 Tox=√2 Capacitance=√2 Voltage=√2 Current=√2 Area=2x Delay=√2x Power=2x
But….
Wire scaling
W
L H
R=ρL/(W*H)
CunitL = ε*W/T
T τ = R*C
W
L H
L/√2
W/√2 R=ρL/(W*H)
CunitL = ε*W/T
τ = R*C
MIT 6-884/Horowitz
W
L H
L/√2
W/√2 R=ρL/(W*H)
R=ρ(L/√2)/ (W/√2)*H)
R=ρL/(W*H) MIT 6-884/Horowitz
W
L H
L/√2
W/√2 CunitL = ε*W/T
C unitL= ε* (W/√2)/T
MIT 6-884/Horowitz
W
L H
L/√2
W/√2 R=same
C unitL = √2
τ = √2
MIT 6-884/Horowitz
W
L H
W/√2
L
MIT 6-884/Horowitz
R=ρL/(W*H)
R=ρL/((W/√2)*H)
R=√2 *ρL/(W*H)
W
L H
W/√2 R=√2
C = same
τ = √2
L
MIT 6-884/Horowitz
ITRS roadmap
n drain
insulator
metal gate
n source
MIT 6-884 lecture slides
Leakage
Power-Performance Inflection at 90 nm Process Node - FPGAs in Focus - ChipDesign
Summarize
• Architecture is an abstraction
– It is NOT black magic..
• Closely tied to Fab. technology
– Conventional scaling will eventually end….
• Gate delay vs. Wire delay
– Rethink microarchitecture
• Upcoming challenges
– Power/Vth/Leakage=> Energy efficient design!
Parthenon
"Look," said Roark. "The famous flutings on the famous
columns---what are they there for? To hide the joints in wood-
--when columns were made of wood, only these aren't,
they're marble. The triglyphs, what are they? Wood. Wooden
beams, the way they had to be laid when people began to
build wooden shacks. Your Greeks took marble and they made
copies of their wooden structures out of it, because others
had done it that way. Then your masters of the Renaissance
came along and made copies in plaster of copies in marble of
copies in wood. Now here we are making copies in steel and
concrete of copies in plaster of copies in marble of copies in
wood. Why?
Clifton Bridge - Bristol
1864 Inspired by Henry Petroski’s Talk at UPenn
Tay Bridge - Dundee
1880