1. POLITECNICO DI MILANO
Introduction to HLR
Reconfigurable Computing Italian Meeting
19 December 2008
Room S01, Politecnico di Milano - Milan (Italy)
Francesco Redaelli: fredaelli@elet.polimi.it

2. Motivations
Reconfigurable systems, while providing new
interesting features in the field of hardware/software
co-design, and more in general in the embedded
system design, also introduce new problems in their
implementation and management.
This is particularly true for systems that implement
self partial reconfiguration, such as Xilinx platforms.
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3. Behavioral and Structural flexibility
Speedup the overall computation of the final system
Increasing need for behavioral flexibility in embedded
systems design
Support of new standards, e.g. in media processing
Addition of new features
New applications too large to fit on the device all at
once
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4. Reconfiguration challenges
Reconfiguration times heavily impact on the final
solution’s latency
Hiding reconfiguration time is not sufficient
Possible solution:
Trivial
Bitstream dimension reduction
Complex
Maximize the reuse of configured modules
Reconfiguration hiding
Alternative implementation (SW execution)
Relocation
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5. Design Flow
Design Flow divided in three phases in order to reduce
the complexity and allow for each phase specific
algorithms.
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6. Tasks reuse
Reconfiguration times impact heavily on the final
solution’s latency, therefore:
Not only try to hide the reconfigurations
But try to maximize the reuse of reconfigurable modules
Schedule length is on
average at least 18.6%
better than the shortest
one and 19.7% better than
the average.
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7. Reconfiguration hiding
Area Area
A
A
B
B
Reconf
Reconf
Reconf
C D
Reconf
D
E
Reconf
C
F
Reconf
E
F
Time
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8. Relocation: Scenario
Area
RFU
A possible scenario
Implementations
A
B B
A
2/1 A B 1/2 Rec. C
RR1 RR2 RR3 RR1 RR2 RR3
C
2/2 C
D
C Rec. D
D 1/1 D
RR1 RR2 RR3 RR1 RR2 RR3
Rec. E
E
E 1/1 E F Rec. F
RR1 RR2 RR3 RR1 RR2 RR3
Time
F
F 2/2
Legenda:
Time
Fi
Area/Time
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9. Relocation: Motivation
A possible scenario
2/1 A B 1/2
C
2/2
D 1/1
E 1/1
Time
F 2/2
Legenda:
Fi
Area/Time
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10. Relocation: Motivation
A possible scenario Area
RFU
Implementations
2/1 A B 1/2 A B A
B
RR1 RR2 RR3 RR1 RR2 RR3
Rec. C
C
2/2
R2 D
C D
D
D 1/1 C
R2 E
RR1 RR2 RR3 RR1 RR2 RR3
R2 F E
E 1/1
E F
F
Time
F RR1 RR2 RR3 RR1 RR2 RR3
2/2
Legenda:
Time
Fi
Area/Time
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11. Questions
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