Upload
jeffry-hoover
View
221
Download
2
Embed Size (px)
Citation preview
Jürgen Lambrecht– DESICS© imec 2002
Multi-objective refinement of Mapping Tables in
Telecom Network Applications
Jürgen Lambrecht, Chantal Ykman-Couvreur, Armin van der Togt,
Francky CatthoorThe Protocol Processor Project (PRO3)
Contract No IST-1999-11449
Jürgen Lambrecht – DESICS© imec 2002
Outline
Introduction Context Example: network switch Related Work Our contribution
Design space and Method Mapping table implementations: primitives Primitives characteristics Mapping table implementations: multi-layer Exploration Method System Level Cost Factors
Results Multi Objective Exploration Impact of network Impact of operation characteristics
Future work and Conclusions
Jürgen Lambrecht – DESICS© imec 2002
Context
Data type refinement
Mapping tables
Application domain: telecom network, database, multimedia, ...
Design Technology for Integrated Information and Communication Systems
Memory system: bottleneck
Methodology: system level specification optimised embedded implementation
Jürgen Lambrecht – DESICS© imec 2002
Example: network switch
port 1
Port 2
x2 5Y2 1
Y2 5x4 7
ATMMUX
ATMMUX
2 = 0000 0010
2 = 0000 0010
5 = 0000 0000 0000 0101
1 = 0000 0000 0000 0001
1 = 0000 0001
1 = 0000 0001
4 = 0000 01007 = 0000 0000 0000 01112 = 0000 0010
2 = 0000 00105 = 0000 0000 0000 01012 = 0000 0010
Key1 ( VPI[8] ) Key3 ( port[8] ) { VPI, VCI, port } [32]Key2 ( VCI[16] )Table (with active
connections)16 284 MB
Jürgen Lambrecht – DESICS© imec 2002
Related Work
Programming theory STL
SETL
Embedded systems imec - Wuytack et al. 1996
Design space characterisation for mapping tablesPreliminary exploration and optimisation method
imec - Ykman et al. ISSS 1999
Extended design space (key merging/splitting)Improved cost function
Jürgen Lambrecht – DESICS© imec 2002
Our contribution
Area
Power
Objective trade-off
With all relevant application characteristics
Automated fast exploration and optimisation
simulates the application
collects profiling info
runs the tool
pareto curves resultGoal:
optimised implementation
trade-off multiple objectives
taking all relevant system characteristics into account
Jürgen Lambrecht – DESICS© imec 2002
Outline
Introduction Context Example: network switch Related Work Our contribution
Design space and Method Mapping table implementations: primitives Primitives characteristics Mapping table implementations: multi-layer Exploration Method System Level Cost Factors
Results Multi Objective Exploration Impact of network Impact of operation characteristics
Future work and Conclusions
Jürgen Lambrecht – DESICS© imec 2002
Mapping table implementations: primitives
keydata
keydata
keydata
Linked List (LL) keydata
Array (AR)
data
data
data
data
Pointer Array (PA)
data
data
data
data
Jürgen Lambrecht – DESICS© imec 2002
Primitives' characteristics
50 Kb M acc/sec mW sec0
25
50
75
100
125
150
175
200
225
250
275
300
325
AR
PA
LL
Jürgen Lambrecht – DESICS© imec 2002
Mapping table implementations: multi-layer
Lay
er 1
key1key1key1key1
LL(7)
Lay
er 2
PA(4)2 4
Lay
er 3
AR(3)
data
data
data
data
data
data
data
Jürgen Lambrecht – DESICS© imec 2002
Exploration method
Key ordering
Key hashing
Key concatenation
Key splitting
2 = 0000 0010
2 = 0000 0010
5 = 0000 0000
0000 0101
1 = 0000 0000
0000 0001
1 = 0000 0001
1 = 0000 0001
4 = 0000 0100
7 = 0000 0000 0000 0111
2 = 0000 0010
2 = 0000 0010
5 = 0000 0000 0000 0101
2 = 0000 0010
Key1 ( VPI[8] ) Key3 ( port[8] ) { VPI, VCI, port } [32]Key2 ( VCI[16] )
port 1
Port 2
x2 5Y2 1
Y2 5
x4 7
ATMMUX
Jürgen Lambrecht – DESICS© imec 2002
Exploration method
Key ordering
Key hashing
Key concatenation
Key splitting
Assignment of primitivesCost vector calculation
Lay
er 1
key1key1key1key1
LL(7)L
ayer
2
PA(4)24
Lay
er 3 AR(3)
data
data
data
data
data
data
data
Jürgen Lambrecht – DESICS© imec 2002
System Level Cost Factors
Application characteristics
Data: size, average number
Keys: size, average number, dependencies, frequency distributions
Operations: accesses and proportion
AR(3)
data
data
data
data
data
data
data
PA(4)24
Memory cost Area: bits Performance: accesses Power: vendor model
Jürgen Lambrecht – DESICS© imec 2002
Outline
Introduction Context Example: network switch Related Work Our contribution
Design space and Method Mapping table implementations: primitives Primitives characteristics Mapping table implementations: multi-layer Exploration Method System Level Cost Factors
Results Multi Objective Exploration Impact of network Impact of operation characteristics
Future work and Conclusions
Jürgen Lambrecht – DESICS© imec 2002
Multi Objective Exploration
DifferenceFactor
2 in size5 in power
8 in accesses2 in performance
Jürgen Lambrecht – DESICS© imec 2002
Impact of network
Jürgen Lambrecht – DESICS© imec 2002
Impact of operation characteristics
Jürgen Lambrecht – DESICS© imec 2002
Future work
Better memory library Off-chip memory support
On/Off-chip partitioning
Include fixed platforms (w. caches…)
Further automation
New primitive data structures Internet multimedia data sets Trees
Jürgen Lambrecht – DESICS© imec 2002
Conclusions
Bottleneck in embedded system synthesis: memory performance, area, and power
our focus: Mapping Tables
Optimisation at system level
Automated method needed Multi-objective exploration All relevant application characteristics Fast Power-objective result
90% area savings80% power savingswithout decreasing the performance
Jürgen Lambrecht – DESICS© imec 2002
www.imec.beWorldwide collaboration with more than 450 companies and institutes.
IMEC – Kapeldreef 75 – B-3001 Leuven – Belgium – Tel. +32 16 281211 – Fax +32 16 229400 – www.imec.be
Jürgen Lambrecht – DESICS© imec 2002
Dynamic
Memory
Mngnt.
Physical
Memory
Mngnt.
VirtualMemory
Segments
Selecteddata
structures
PhysicalMemories
ADT Abstract Data TypeRefinement
Virtual memory mngntRefinement
Physical memory mngntRefinement
Memory Management in Matisse
Jürgen Lambrecht – DESICS© imec 2002
Exploration and Optimization
Power
Layers
20,000
2,000
200
100
1,000
10,000
1 2 3 4