Transcript Microarchitectural Techniques to Reduce Interconnect Power in

Multi-Cores: Architecture/VLSI
Perspective
The Hardware-Software Relationship:
Date or Dump?
Oct 31st 2007
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Embedded Applications
 From discreet
cochlear implants to
high-end biomedical
imaging!
 Multi-cores speed up
performance by 50x!
 Creating new
application domains!
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--Spencer
Oct 31st 2007
How to use “multiple” cores?
Parallel
programming
Synchronization
Deadlock
Livelock
Memory
management
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Oct 31st 2007
How to use “multiple” cores?
Program =
Communication
+ Computation
 Global restructuring and parallelization
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Oct 31st 2007
Structured “Communication”
Lang: StreamIt, MPI
Compilers: RAW, CoGenE
Architecture: TRIPS,
HWRT
 Key: Help other levels and leverage communication
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Oct 31st 2007
Another Constraint?
Hey..
Surprise!!!
Parallel
programming
Synchronization
Deadlock
Livelock
Memory
management
Communication
Scheduling
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Oct 31st 2007
Another Constraint?
Oh God!!!
Communication
Scheduling
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Oct 31st 2007
Focus of Architecture Research
 Reduce the load of programmers
 Hardware transactional memory
 Aggressive pre-fetching
 Dynamic reconfiguration at every possible level
 Keep the architectural innovations transparent
to compilers or programmers
 Learn from the mistakes of ITANIUM !
 Remember the success of OOO execution
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Reliability Issues
--Niti
 Shrinking transistor sizes & lower voltages

Increased transient faults, process variations – leakage
power and frequency variations, hard errors, interconnect
noise
 Many-core – “Many cores” may not work reliably
 Some cores will end up providing redundancy
 Heterogeneous cores may be able to help
 Simple in-order cores can provide redundancy at low cost
 The compute power gain of many-core can get offset
by reliability requirements of the system
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Oct 31st 2007
On-Chip Sensor Networks
--Nathaniel, Amlan
Analog sensors everywhere!
 Need to monitor power, voltage droop,
variation, critical paths, delays, slew
rates, etc.
 Control system to react to changes.
 In multi-core, sensor network will only
grow.
On-chip sensors
Xeon and Itanium processors JSSC Jan 06 & 07
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