Transcript Hydraulic Modelling CPU Vs GPU June 18, 2014

The Need for
Speed in Flood
Modelling
November 13, 2014
Richard Connell
Ben Tate
Lachlan Inglis
Vs
Recent Changes to Hydraulic Modelling
• Limitation:
•‘Traditional’ implicit hydraulic model schemes run on a single-core
• Recent advances in computing power are in multi-core & parallelisation
• Solution:
• Transition to ‘explicit’ hydraulic model schemes that can be parallelised to
run on multi-core systems
Compute Performance History
Processor Comparison
Chip
Processing Cores
Clock Speed
Single Precision Performance
Double Precision Performance
Peak Power Usage
CPU
GPU
Intel - i7-5960X
Nvidia – Titan Black
Processor Comparison
Chip
Processing Cores
Clock Speed
Single Precision Performance
Double Precision Performance
Peak Power Usage
CPU
GPU
Intel - i7-5960X
Nvidia – Titan Black
8 (16)
2880
Processor Comparison
Chip
Processing Cores
Clock Speed
Single Precision Performance
Double Precision Performance
Peak Power Usage
CPU
GPU
Intel - i7-5960X
Nvidia – Titan Black
8 (16)
2880
3.5 GHz
1.17 GHz
Processor Comparison
Chip
Processing Cores
Clock Speed
Single Precision Performance
Double Precision Performance
Peak Power Usage
CPU
GPU
Intel - i7-5960X
Nvidia – Titan Black
8 (16)
2880
3.5 GHz
1.17 GHz
350 GFLOPS
5,000 GFLOPS
Processor Comparison
CPU
GPU
Intel - i7-5960X
Nvidia – Titan Black
8 (16)
2880
3.5 GHz
1.17 GHz
Single Precision Performance
350 GFLOPS
5,000 GFLOPS
Double Precision Performance
175 GFLOPS
1,700 GFLOPS
Chip
Processing Cores
Clock Speed
Peak Power Usage
Processor Comparison
CPU
GPU
Intel - i7-5960X
Nvidia – Titan Black
8 (16)
2880
3.5 GHz
1.17 GHz
Single Precision Performance
350 GFLOPS
5,000 GFLOPS
Double Precision Performance
175 GFLOPS
1,700 GFLOPS
140 Watts
250 Watts
Chip
Processing Cores
Clock Speed
Peak Power Usage
Hydraulic Models: TUFLOW
TUFLOW Classic
Scheme
Implicit
Finite Difference
Domains
1D & 2D (GRID)
Inflow Boundaries
Outflow
Boundaries
Flux, source
points, rainfall
Water level, rating
curve
TUFLOW GPU
Hydraulic Models: TUFLOW
TUFLOW Classic
TUFLOW GPU
Scheme
Implicit
Finite Difference
Explicit
Finite Volume
Domains
1D & 2D (GRID)
2D (GRID)
Flux, source
points, rainfall
Source points,
rainfall
Water level, rating
curve
Water level
Inflow Boundaries
Outflow
Boundaries
Hydraulic Models: MIKE by DHI
MIKE Classic
Scheme
Implicit
Finite Difference
Domains
1D & 2D (GRID)
Inflow Boundaries
Outflow
Boundaries
Flux, source
points, rainfall
Water level, rating
curve
MIKE GPU
Hydraulic Models: MIKE by DHI
MIKE Classic
MIKE GPU
Scheme
Implicit
Finite Difference
Explicit
Finite Volume
Domains
1D & 2D (GRID)
1D & 2D (MESH)
Flux, source
points, rainfall
Flux, source
points, rainfall
Water level, rating
curve
Water level, rating
curve
Inflow Boundaries
Outflow
Boundaries
Woorabinda Case Study
• Study area = 29.9 sq km
• Grid Size = 10 m
• Cells/ Elements = 300,000
• All 2D (no structures)
• Single inflow hydrograph
• Downstream water level boundary
• Hydraulic Models Tested
• TUFLOW Classic
• TUFLOW GPU
• MIKE Classic
• MIKE FM CPU
• MIKE FM GPU – 1st Order
• MIKE FM GPU – 2nd Order
Woorabinda Case Study
Woorabinda Case Study
TUFLOW TUFLOW
Classic
GPU
1st Order
Scheme
Implicit
Simulation
14h 44m
Time
Time Step
MIKE
Classic
MIKE
FM CPU
MIKE
MIKE FM
FM GPU
GPU
2nd Order 1st Order
Explicit
Implicit
Explicit
Explicit
Explicit
0h 24m
2h 58m
30h 56m
3h 6m
1h 48m
Woorabinda Case Study
TUFLOW TUFLOW
Classic
GPU
1st Order
Scheme
Implicit
Simulation
14h 44m
Time
Time Step
3s
MIKE
Classic
MIKE
FM CPU
MIKE
MIKE FM
FM GPU
GPU
2nd Order 1st Order
Explicit
Implicit
Explicit
Explicit
Explicit
0h 24m
2h 58m
30h 56m
3h 6m
1h 48m
1.43s
3s
0.38s
0.39s
0.38s
Woorabinda Case Study
TUFLOW TUFLOW
Classic
GPU
1st Order
Scheme
Implicit
Explicit
Simulation
14h 44m
Time
Time Step
3s
1.43s
MIKE
Classic
MIKE
FM CPU
Implicit
Explicit
2h 58m
30h 56m
3s
0.38s
MIKE
MIKE FM
FM GPU
GPU
2nd Order 1st Order
Explicit
Explicit
0.39s
0.38s
Woorabinda Case Study
TUFLOW TUFLOW
Classic
GPU
1st Order
Scheme
Implicit
Simulation
14h 44m
Time
Time Step
3s
MIKE
Classic
MIKE
FM CPU
MIKE
MIKE FM
FM GPU
GPU
2nd Order 1st Order
Explicit
Implicit
Explicit
Explicit
Explicit
0h 24m
2h 58m
30h 56m
3h 6m
1h 48m
1.43s
3s
0.38s
0.39s
0.38s
Woorabinda Case Study
CPU Vs GPU Benchmarking Summary
• Pros:
• Significant speed-up for large models
• Larger models and finer grid resolutions are now possible
• Cons:
• Accuracy of results
• Feature limitations
Example Applications – Loddon Valley
• Loddon Valley:
• 65 km x 48 km
• 5 million grid cells
• 10 day flood event
• 25 m grid resolution • Run time: 1 hour
Example Applications – Goulburn River
154 Hours
• Previous Model Setup:
50 Hours
• 8 Separate 1D/2D hydraulic models
37 Hours
• 25 m grid resolution
• Average 9 day flood event
27 Hours
• Total Run time: 390 hours
30 Hours
22 Hours
30 Hours
40 Hours
Example Applications – Goulburn River
• Upper Model:
• Lower Model:
• 85 km x 65 km
• 64 km x 80 km
• 10 m grid resolution
• 10 m grid resolution
• 55 million cells
• 50 million cells
• 10 day flood event
• 10 day flood event
• Run time: 25 hours
• Run time: 20 hours
CPU Vs GPU Conclusions
• Significant reduction in model run times are possible
• Much larger model extents and smaller grid resolutions possible
• Suitable for:
• Rapid large scale flood assessment
• Rapid assessment of mitigation options
• Real-time flood warning
• Not suitable for:
• Detailed flood mapping … Yet!