My presentation for the 23rd PhD Minisymposium on the challenges of benchmarking Java applications.

1. Budapest University of Technology and Economics
Department of Measurement and Information Systems
Budapest University of Technology and Economics
Fault Tolerant Systems Research Group
Towards a Macrobenchmark Framework
for Performance Analysis of Java Applications
Gábor Szárnyas, Dániel Varró

2. Performance
issues
Model-Driven Development
Modeling
Code
generation
Testing
Early validations
Transformations
Scalability
challenges

3. Model Sizes
 Models = graphs with 100M–1B elements
o Car industry
o Avionics
o Software analysis
o Cyber-physical systems
Source: Markus Scheidgen, Automated andTransparent
Model Fragmentation for Persisting Large Models, 2012
application model size
software models 108
sensor data 109
geo-spatial models 1012
Validation may take hours

4. Research Goal
 Scalable query engine for evaluating complex
queries on large models.
 Latest results are presented in tomorrow’s
session:
o János Maginecz, Gábor Szárnyas:
Sharded Joins for Scalable Incremental Graph Queries
 Today: benchmarking

5. Motivation
 Jennifer Widom: Tips for Writing Technical Papers
 On performance experiments:
It’s easy to do “hokey” or meaningless
experiments, and many papers do.
Many conferences expect experiments.

6. Benchmarks in Software Engineering
 Performance experiments = benchmarks
 Common goals
o Compare various tools
o Derive performance metrics
o Assess the scalability of the system
 Microbenchmarks
o Method-level
o Very difficult and not recommended
 Macrobenchmarks
o Application-level

7. INCQUERY-D Architecture
Server 1
Database
shard 1
Server 2
Database
shard 2
Server 3
Database
shard 3
Transaction
Database
shard 0
Server 0
Distributed query evaluation network
Distributed indexer Model access adapter

8. INCQUERY-D Architecture
Server 1
Database
shard 1
Server 2
Database
shard 2
Server 3
Database
shard 3
Transaction
Database
shard 0
Server 0
Distributed query evaluation network
Distributed indexer Model access adapter
Distributed storage

9. INCQUERY-D Architecture
Server 1
Database
shard 1
Server 2
Database
shard 2
Server 3
Database
shard 3
Transaction
Database
shard 0
Server 0
Distributed query evaluation network
Distributed indexer Model access adapter
Distributed indexing
Distributed storage

10. INCQUERY-D Architecture
Server 1
Database
shard 1
Server 2
Database
shard 2
Server 3
Database
shard 3
Transaction
Database
shard 0
Server 0
Distributed query evaluation network
Distributed indexer Model access adapter
Distributed indexing
Distributed storage
Distributed query network

11. INCQUERY-D Architecture
Server 1
Database
shard 1
Server 2
Database
shard 2
Server 3
Database
shard 3
Transaction
Database
shard 0
Server 0
Distributed query evaluation network
Distributed indexer Model access adapter

12. INCQUERY-D Architecture
Server 1
Database
shard 1
Server 2
Database
shard 2
Server 3
Database
shard 3
Transaction
Database
shard 0
Server 0
Distributed query evaluation network
Indexer Indexer Indexer Indexer
Join
Join
Antijoin

13. INCQUERY-D Architecture
Server 1
Database
shard 1
Server 2
Database
shard 2
Server 3
Database
shard 3
Transaction
Database
shard 0
Server 0
Distributed query evaluation network
Indexer Indexer Indexer Indexer
Join
Join
Antijoin
Separate processes

14. Operating System
Server 1
Database
shard 1
Server 2
Database
shard 2
Server 3
Database
shard 3
Transaction
Database
shard 0
OS OS OS OS
Server 0
Indexer Indexer Indexer Indexer
Join
Join
Antijoin
• File system caching
• Scheduled jobs
• Swapping

15. Cloud Noise
Server 1
Database
shard 1
Server 2
Database
shard 2
Server 3
Database
shard 3
Transaction
Database
shard 0
OS OS OS OS
Server 0
Indexer Indexer Indexer Indexer
Join
Join
Antijoin
Other VMs running
on the same server

16. Parallel Execution
Server 1
Database
shard 1
Server 2
Database
shard 2
Server 3
Database
shard 3
Transaction
Database
shard 0
OS OS OS OS
Server 0
Indexer Indexer Indexer Indexer
Join
Join
Antijoin
Multiple processes
in the same OS
Multithreaded
processes

17. Threats to Validity
 Operating system: caching, scheduled jobs
 Parallel processes
 Multithreaded execution
 Environmental noise in the cloud
 The hardest: Managed Runtime Environments
o Java Virtual Machine
o .NET CLR

18. Managed Runtime Environments
Just-in-time
compilation
Runtime
optimization

19. The Effect of Warmup
First
execution time
Median
execution time
of 5 executions
Two Java-based
query engines
Perform
multiple
executions

20. CASE STUDY:
THE TRAIN BENCHMARK
Gábor Szárnyas, Benedek Izsó, István Ráth, Dániel Varró
2016

21. Database Benchmarks
Criteria for domain-specific benchmarks
(Jim Gray, Benchmark Handbook, 1993):
 Relevant
 Scaleable
 Portable
 Simple
Two-phase commit, data cubes,
ACID transactions

22. The Train Benchmark
 Domain: railway network validation
 Goal: measure the scalability of query evaluation
 Supports various representations
 Randomly generated instance models
o Increasing sizes
o Close to real-world instances
o Faults are inserted during generation

23. Railway Model
 Synthetic model
 Customizable model generator
Semaphore
Route
Segment
Switch
Entry
Exit
Switch position
of the Route
Current
position
of the Switch

24. Validation Queries
 Well-formedness constraints
 Queries are looking for error patterns
o Lots of filtering, joins, etc.
 Transformations
o Fault injections
o Quick fix-like repair operations

25. Benchmark Phases
1. Load 3. Transform 4. Revalidate2. Validate
Iteration: × 10Run: × 5
Change set size
Model
increasing
size
Query Measure-
ments
 Framework features
o Automated build and unit testing
o Automated visualization
Warmup
Warmup

26. Model Transformation
7 OOMs

27. Some Conclusions
 Very hard to tell the actual memory consumption
o Manual calls to the garbage collector – not enough
o Profiler – still not enough
o Setting a hard limit is the best approach
 Benchmarking is difficult
o Lots of factors can add noise to the results
o Nothing works on the first try
 Visualization helps a lot
o Worth investing time to learn R
o Not a nice language, but very productive

28. Related Publications
Benchmark framework
 Szárnyas, G., Izsó, B., Ráth, I., and Varró, D.,
The Train Benchmark for Evaluating the Performance of Continuous Model
Validation, SOSYM journal (work-in-progress)
 Izsó, B., Szárnyas, G., Ráth, I., and Varró, D.,
MONDO-SAM: A Framework to Systematically Assess MDE Scalability,
2nd Workshop on Scalable Model Driven Engineering, 2014
Benchmark applications
 Szárnyas, G., Semeráth, O., Ráth, I., and Varró, D.,
The TTC 2015 Train Benchmark Case for Incremental Model Validation,
Transformation Tool Contest, 2015
 Szárnyas, G., Izsó, B., Ráth, I., Harmath, D., Bergmann, G., and Varró, D.,
IncQuery-D: A Distributed Incremental Model Query Framework in the Cloud,
ACM/IEEE 17th International Conference on Model Driven Engineering Languages
and Systems, 2014
 Izsó, B., Szárnyas, G., Ráth, I., and Varró, D.,
IncQuery-D: Incremental Graph Search in the Cloud,
Proceedings of the Workshop on Scalability in Model Driven Engineering, 2013

29. Ω