A Comprehensive Study on the Energy Efficiency of Java Thread-Save Collections

Transcript

1. A Comprehensive Study on
   the Energy Efficiency of Java
   Thread-Safe Collections
   Fernando Castor
   Kenan Liu
   Gustavo Pinto David Liu
   1
   

   View Slide

2. Disclaimer
   2
   

   View Slide

3. 3
   Miguel
   turns
   8mo
   today!
   

   View Slide

4. Motivations
   4
   

   View Slide

5. First, energy consumption is not only a concern for
   unwired devices, but also for data centers
   5
   

   View Slide

6. First, energy consumption is not only a concern for
   unwired devices, but also for data centers
   6
   Second, multicore CPUs are ubiquitous
   

   View Slide

7. First, energy consumption is not only a concern for
   unwired devices, but also for data centers
   7
   Second, multicore CPUs are ubiquitous
   Third, data structures are the fundamentals of
   computer programming
   

   View Slide

8. In case you are a Java
   programmer…
   8
   

   View Slide

9. 9
   List lists = …;
   • ArrayList
   • LinkedList
   

   View Slide

10. 10
    List lists = new ArrayList<>();
    

    View Slide

11. 11
    List lists = new ArrayList<>();
    Thread
    

    View Slide

12. 12
    • ArrayList
    • LinkedList
    • Vector
    • Collections.synchronizedList()
    • CopyOnWriteArrayList
    List lists = …;
    Non Thread-Safe
    Thread-Safe
    

    View Slide

13. 13
    List lists = new Vector<>();
    

    View Slide

14. 14
    List lists = new Vector<>();
    Thread
    

    View Slide

15. 15
    Thread
    Thread-safe!
    List lists = new Vector<>();
    

    View Slide

16. 16
    Thread
    {
    }
    …
    List lists = new Vector<>();
    

    View Slide

17. 17
    Thread
    {
    }
    …
    List lists = new Vector<>();
    

    View Slide

18. 18
    List lists = new CopyOnWriteArrayList<>();
    

    View Slide

19. 19
    Thread
    Thread-safe!
    List lists = new CopyOnWriteArrayList<>();
    

    View Slide

20. List lists = new CopyOnWriteArrayList<>();
    20
    {
    }
    Thread
    Thread-safe!
    

    View Slide

21. 21
    List lists = …;
    • ArrayList
    • LinkedList
    • Vector
    • Collections.synchronizedList()
    • CopyOnWriteArrayList
    Non Thread-Safe
    Thread-Safe
    

    View Slide

22. 22
    List lists = …;
    Set sets = …;
    Map maps = …;
    

    View Slide

23. 23
    List lists = …;
    Set sets = …;
    Map maps = …;
    

    View Slide

24. 24
    List lists = …;
    Set sets = …;
    Map maps = …;
    And how about
    energy consumption?
    

    View Slide

25. 16 Collections
    25
    List
    ArrayList
    Vector
    Collections.syncList()
    CopyOnWriteArrayList
    Set
    LinkedHashSet
    Collections.syncSet()
    CopyOnWriteArraySet
    ConcurrentSkipListSet
    ConcurrentHashSet
    ConcurrentHashSetV8
    Map
    LinkedHashMap
    Hashtable
    Collections.syncMap()
    ConcurrentSkipListMap
    ConcurrentHashMap
    ConcurrentHashMapV8
    

    View Slide

26. 16 Collections
    26
    List
    ArrayList
    Vector
    Collections.syncList()
    CopyOnWriteArrayList
    Set
    LinkedHashSet
    Collections.syncSet()
    CopyOnWriteArraySet
    ConcurrentSkipListSet
    ConcurrentHashSet
    ConcurrentHashSetV8
    Map
    LinkedHashMap
    Hashtable
    Collections.syncMap()
    ConcurrentSkipListMap
    ConcurrentHashMap
    ConcurrentHashMapV8
    Non thread-safe
    Thread-safe
    

    View Slide

27. 16 Collections
    27
    List
    ArrayList
    Vector
    Collections.syncList()
    CopyOnWriteArrayList
    Set
    LinkedHashSet
    Collections.syncSet()
    CopyOnWriteArraySet
    ConcurrentSkipListSet
    ConcurrentHashSet
    ConcurrentHashSetV8
    Map
    LinkedHashMap
    Hashtable
    Collections.syncMap()
    ConcurrentSkipListMap
    ConcurrentHashMap
    ConcurrentHashMapV8
    Java 7
    Java 8
    

    View Slide

28. 16 Collections
    28
    List
    ArrayList
    Vector
    Collections.syncList()
    CopyOnWriteArrayList
    Set
    LinkedHashSet
    Collections.syncSet()
    CopyOnWriteArraySet
    ConcurrentSkipListSet
    ConcurrentHashSet
    ConcurrentHashSetV8
    Map
    LinkedHashMap
    Hashtable
    Collections.syncMap()
    ConcurrentSkipListMap
    ConcurrentHashMap
    ConcurrentHashMapV8
    x 3 Operations
    Traversal Insertion Removal
    

    View Slide

29. 2 Environments
    AMD CPU: A 2×16-core, running Debian, 2.4 GHz,
    64GB of memory, JDK version 1.7
    .0 11, build 21.
    29
    Intel CPU: A 2×8-core (32-cores w/ hyper-threading),
    running Debian, 2.60GHz, with 64GB of memory, JDK
    version 1.7
    .0 71, build 14.
    

    View Slide

30. 2 Environments
    AMD CPU: A 2×16-core, running Debian, 2.4 GHz,
    64GB of memory, JDK version 1.7
    .0 11, build 21.
    30
    Intel CPU: A 2×8-core (32-cores w/ hyper-threading),
    running Debian, 2.60GHz, with 64GB of memory, JDK
    version 1.7
    .0 71, build 14.
    Hardware-based energy measurement
    Software-based energy measurement
    

    View Slide

31. 31
    More details about how the experiments
    were conducted?
    http:/
    /icsme2016.github.io/program/accepted.html
    

    View Slide

32. Results
    32
    

    View Slide

33. 33
    Traversal Insertion Removal
    Intel CPU
    AMD CPU
    Traversal Insertion Removal
    Lists
    

    View Slide

34. 34
    ArrayList Vector
    Lists
    Collections.synchronizedList()
    

    View Slide

35. 35
    Lists
    ArrayList Vector
    Collections.synchronizedList()
    Energy (Joules)
    

    View Slide

36. 36
    Lists
    ArrayList Vector
    Energy (Joules) Power (Watts)
    Collections.synchronizedList()
    

    View Slide

37. 37
    Lists
    ArrayList Vector
    Energy (Joules) Power (Watts)
    Collections.synchronizedList()
    

    View Slide

38. Traversal Insertion Removal
    Intel CPU
    AMD CPU
    38
    38
    Traversal Insertion Removal
    Lists
    

    View Slide

39. 39
    Traversal Insertion Removal
    Intel CPU
    AMD CPU
    39
    Traversal Insertion Removal
    Lists
    

    View Slide

40. 40
    Maps
    Intel CPU
    Traversal Insertion Removal
    AMD CPU
    Traversal Insertion Removal
    

    View Slide

41. 41
    Maps
    Intel CPU
    Traversal Insertion Removal
    AMD CPU
    Traversal Insertion Removal
    

    View Slide

42. 42
    Maps
    Intel CPU
    Traversal Insertion Removal
    AMD CPU
    Traversal Insertion Removal
    

    View Slide

43. 43
    Maps
    Intel CPU
    Traversal Insertion Removal
    AMD CPU
    Traversal Insertion Removal
    

    View Slide

44. 44
    Maps
    Intel CPU
    Traversal Insertion Removal
    AMD CPU
    Traversal Insertion Removal
    

    View Slide

45. 45
    Maps
    Intel CPU
    Traversal Insertion Removal
    AMD CPU
    Traversal Insertion Removal
    

    View Slide

46. 46
    Maps
    Intel CPU
    Traversal Insertion Removal
    AMD CPU
    Traversal Insertion Removal
    Less energy than the non thread-safe
    implementation!
    

    View Slide

47. Case Study
    47
    

    View Slide

48. 48
    Tomcat
    > A web server
    > More than 170K lines of Java code
    > More than 300 Hashtables
    

    View Slide

49. 49
    Tomcat
    Xalan
    > Parses XML in HTML documents
    > More than 188K lines of Java code
    > More than 140 Hashtables
    > A web server
    > More than 170K lines of Java code
    > More than 300 Hashtables
    

    View Slide

50. 50
    For each Hashtable
    instance, change it for
    a ConcurrentHashMap
    one. Do it again for
    ConcurrentHashMapV8
    Task:
    

    View Slide

51. 51
    Tomcat
    Hashtable to CHM: -12.21%
    Hashtable to CHM8: -17
    .82%
    

    View Slide

52. 52
    Tomcat Xalan
    Hashtable to CHM: -12.21%
    Hashtable to CHM8: -17
    .82%
    Hashtable to CHM: -5.82%
    Hashtable to CHM8: -9.32%
    

    View Slide

53. 53
    So, lets change all Hashtable
    instances to ConcurrentHashMap!
    Not so fast, young padawan…
    

    View Slide

54. 54
    Hashtable ConcurrentHashMap
    Map 

    implements
    

    View Slide

55. 55
    Hashtable ConcurrentHashMap
    Cloneable 

    Map 

    implements
    

    View Slide

56. 56
    Hashtable ConcurrentHashMap
    List obj = new Hashtable<>();
    obj.clone();
    Cloneable 

    Map 

    /
    / works fine
    implements
    

    View Slide

57. 57
    Hashtable ConcurrentHashMap
    List obj = new Hashtable<>();
    obj.clone();
    Cloneable 

    Map 

    /
    / works fine
    /
    / compiler error
    implements
    List obj = new ConcurrentHashMap<>();
    obj.clone();
    

    View Slide

58. 58
    Hashtable ConcurrentHashMap
    List obj = new Hashtable<>();
    obj.clone();
    Cloneable 

    Map 

    /
    / works fine
    /
    / compiler error
    implements
    List obj = new ConcurrentHashMap<>();
    obj.clone();
    Danny Dig
    Opportunity for improving
    refactoring tools!
    

    View Slide

59. Take Away Messages
    59
    

    View Slide

60. 60
    Small changes can have
    GREAT impacts, when it
    comes to energy
    consumption
    

    View Slide

61. 61
    Doug Lea
    Stay up-to-date with the
    new releases of the
    java.util.concurrent library
    

    View Slide

62. In Summary
    62
    

    View Slide

63. View Slide

64. 64
    THANKS
    

    View Slide

65. A Comprehensive Study on
    the Energy Efficiency of Java
    Thread-Safe Collections
    Fernando Castor
    Kenan Liu
    Gustavo Pinto David Liu
    65
    

    View Slide

66. Experimental Environments
    66
    AMD CPU: A 2×16-core, running Debian, 2.4 GHz,
    64GB of memory, JDK version 1.7
    .0 11, build 21.
    Intel CPU: A 2×8-core (32-cores w/ hyper-threading),
    running Debian, 2.60GHz, with 64GB of memory, JDK
    version 1.7
    .0 71, build 14.
    

    View Slide

67. 67
    Maps (scaling number of threads)
    Intel CPU
    Traversal
    Insertion
    

    View Slide