Thomas R. W. Scogland (LLNL/CASC, Green500)

Re-Visiting Power
Measurement for the
Green500
Thomas R. W. Scogland (LLNL/CASC, Green500)
EE HPC
Working Group
http://eehpcwg.lbl.gov/
New Considerations for the Level 1 Measurement Methodology
1
The Green500 List and its Continuing
Evolution BoF, November 2014
http://www.green500.org
Level 1 Requirements
• Workload phase: Measure at least 20% of
the middle 80% of the core phase
• Machine fraction: Measure at least 1/64th of
the system or 1kW, whichever is greater
• Subsystems measured: Measure the
compute components, network, storage
and other subsystems are not required
2
EE HPC
Working Group
http://eehpcwg.lbl.gov/
New Considerations for the Level 1 Measurement Methodology
The Green500 List and its Continuing Evolution BoF, November 2014
http://www.green500.org
Workload Phase:
A classic HPL Profile
400
Power (kW)
350
Nearly flat,
except…
300
Job launch
Job cleanup
250
0
EE HPC
Working Group
http://eehpcwg.lbl.gov/
10000
20000
3
Time from start (seconds)
New Considerations for the Level 1 Measurement Methodology
The Green500 List and its Continuing Evolution BoF, November 2014
http://www.green500.org
The Core Phase
• The time period under test
• Possible core phases:
• Job scheduling -> Job completion
• Application start -> application end
• Benchmark start -> benchmark end
• Any is valid, so long as it matches your
other metrics
4
EE HPC
Working Group
http://eehpcwg.lbl.gov/
New Considerations for the Level 1 Measurement Methodology
The Green500 List and its Continuing Evolution BoF, November 2014
http://www.green500.org
The Core Phase:
Linpack Example
Segment
Core
Startup
Tear−down
400
Power (kW)
350
Core phase cuts off most
of the cruft
300
250
EE HPC
Working Group
http://eehpcwg.lbl.gov/
0
10000
20000
5
Time from start (seconds)
New Considerations for the Level 1 Measurement Methodology
The Green500 List and its Continuing Evolution BoF, November 2014
http://www.green500.org
What do we require now?
6
EE HPC
Working Group
http://eehpcwg.lbl.gov/
New Considerations for the Level 1 Measurement Methodology
The Green500 List and its Continuing Evolution BoF, November 2014
http://www.green500.org
Workload Timing by
Measurement Level
Segment
Core
Startup
Tear−down
400
Level 1
Power (kW)
350
20%
Level 2: evenly spaced average measurements
300
Level 3: Continuously integrated energy
250
0
EE HPC
Working Group
http://eehpcwg.lbl.gov/
10000
20000
7
Time from start (seconds)
New Considerations for the Level 1 Measurement Methodology
The Green500 List and its Continuing Evolution BoF, November 2014
http://www.green500.org
Power Variability
Segment
Core
Startup
Tear−down
400
First 20%:
398.1
Power (kW)
350
300
Core phase average:
398.7
250
0
EE HPC
Working Group
http://eehpcwg.lbl.gov/
Last 20%:
398.2
10000
20000
8
Time from start (seconds)
New Considerations for the Level 1 Measurement Methodology
The Green500 List and its Continuing Evolution BoF, November 2014
http://www.green500.org
Why Change the
Requirement?
9
EE HPC
Working Group
http://eehpcwg.lbl.gov/
New Considerations for the Level 1 Measurement Methodology
The Green500 List and its Continuing Evolution BoF, November 2014
http://www.green500.org
Newer system designs
have a different pattern.
10
EE HPC
Working Group
http://eehpcwg.lbl.gov/
New Considerations for the Level 1 Measurement Methodology
The Green500 List and its Continuing Evolution BoF, November 2014
http://www.green500.org
Piz Daint (GPU accelerated)
Linpack Profile
Segment
Core
Startup
Tear−down
Power (kW)
800
Tail-off is
much longer
600
400
0
EE HPC
Working Group
http://eehpcwg.lbl.gov/
2000
4000
6000
8000
11
Time from start (seconds)
New Considerations for the Level 1 Measurement Methodology
The Green500 List and its Continuing Evolution BoF, November 2014
http://www.green500.org
Core Phase Averaged for
Piz Daint
Segment
Core
Startup
Tear−down
Power (kW)
800
First 20%:
873.8
600
Last 20%:
698.4
Core phase average:
833.4
400
200
0
EE HPC
Working Group
http://eehpcwg.lbl.gov/
2000
4000
6000
8000
12
Time from start (seconds)
New Considerations for the Level 1 Measurement Methodology
The Green500 List and its Continuing Evolution BoF, November 2014
http://www.green500.org
Core Phase Averaged for
Piz Daint
Segment
Core
Startup
Tear−down
Power (kW)
800
25%
Lower average
power in the last 20%!
600
400
200
0
EE HPC
Working Group
http://eehpcwg.lbl.gov/
2000
4000
6000
8000
13
Time from start (seconds)
New Considerations for the Level 1 Measurement Methodology
The Green500 List and its Continuing Evolution BoF, November 2014
http://www.green500.org
What do we propose?
14
EE HPC
Working Group
http://eehpcwg.lbl.gov/
New Considerations for the Level 1 Measurement Methodology
The Green500 List and its Continuing Evolution BoF, November 2014
http://www.green500.org
Workload Timing by
Measurement Level
Segment
Core
Startup
Tear−down
400
100%
Level 1
Power (kW)
350
Level 2: evenly spaced average measurements
300
Level 3: Continuously integrated energy
250
0
EE HPC
Working Group
http://eehpcwg.lbl.gov/
10000
20000
15
Time from start (seconds)
New Considerations for the Level 1 Measurement Methodology
The Green500 List and its Continuing Evolution BoF, November 2014
http://www.green500.org
Measurement Fraction
• Level 1 requires 1/64th of the machine
• Which 64th of the machine?
16
EE HPC
Working Group
http://eehpcwg.lbl.gov/
New Considerations for the Level 1 Measurement Methodology
The Green500 List and its Continuing Evolution BoF, November 2014
http://www.green500.org
Variability Across Levels:
SuperMUC
Quality Level
L1
(compute only)
L2 (>10kW)
(compute and interconnect)
L2 (>1/8)
(compute and interconnect)
L3
(compute, interconnect, storage,
cooling, power distribution)
Mflops/Watt full run
Efficiency Drop
From Level 1
1055
0
1011
44 (~4%)
994
61 (~6%)
887
168 (~16%)
17
EE HPC
Working Group
http://eehpcwg.lbl.gov/
A Power-Measurement Methodology for Large-Scale, High-Performance Computing,
International Conference on Performance Engineering, March 2014
http://www.green500.org
Subsystem Contribution
• Networks have been considered “in the
noise” by Level 1 to this point
• We have increasing reports of the network
contributing 10-20% of overall power use
18
EE HPC
Working Group
http://eehpcwg.lbl.gov/
A Power-Measurement Methodology for Large-Scale, High-Performance Computing,
International Conference on Performance Engineering, March 2014
http://www.green500.org
Conclusions
• Our current requirements for level 1 are no longer
sufficient
• We propose raising the requirements of Level 1:
• Measurement phase: 100% of the core phase
• System fraction: 1/16th or more
• Subsystems included: Compute and networking
19
EE HPC
Working Group
http://eehpcwg.lbl.gov/
New Considerations for the Level 1 Measurement Methodology
The Green500 List and its Continuing Evolution BoF, November 2014
http://www.green500.org