1. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 1ETH Zurich – Distributed Computing Group PhD Thesis Raphael Eidenbenz Prof. Roger Wattenhofer, examiner Prof. Dov Monderer, co-examiner Prof. Karl Aberer, co-examiner TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AAAA A A A Coping with Selfishness in Distributed Systems Mechanism Design in Multi-Core and Peer-to-Peer Systems

2. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 2 Selfishness in Computer Science „ The Internet is unique among all computer systems in that it is built, operated, and used by a multitude of diverse economic interests, in varying relationships of collaboration and competition with each other.“ C. Papadimitriou, STOC 2001 Game theory attempts to mathematically capture behavior in strategic situations (games), in which an individual's success in making choices depends on the choices of others.

3. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 3 Game Theory & Mechanism Design Game Theory explains/predicts behavior Mechanism Design Selfishness-aware optimization

4. ETH Zurich – Distributed Computing Group Raphael Eidenbenz 4ETH Zurich – Distributed Computing Group Raphael Eidenbenz Mechanism Design with Payments

5. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 5 Mechanism Design with Payments silenttestify silent 3 0 3 4 testify 4 1 0 1 1 2 1 0 0 0 2 0 + = 4 2 4 4 4 1 2 1 cost = 2 net gain = 2

6. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 6 Optimal Implementations 20 11 10 0 9 11 20 10 90 19 10 9 0 19 11 20 10 19 0 9 10 20 11

7. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 7 20 11 10 11 20 10 19 +1 10 +1 9 +∞ 0 +∞ 10 +1 19 +1 11 20 10 +1 19 +1 0 +∞ 9 +∞ 19 +1 10 +1 20 11 Optimal Implementations

8. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 8 Complexity 5000010 0500010 0050010 0005010 0000510 5005000 0505000 0550500 5550000 1 2 Optimal exact implementation NP-hard

9. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 9 Worst-Case Leverage

10. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 10 Uniform Leverage

11. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 11 Result Overview UniformWorst-case Exact implementation cost NP -hard NP -hard (conjecture) Implementation cost NP -hard NP -hard (conjecture) Singleton implementation cost Polynomial approximation ratio - (Malicious) exact leverage NP -hard - (Malicious) leverage NP -hard As hard as cost Singleton leverage Polynomial approximation ratio -

12. ETH Zurich – Distributed Computing Group Raphael Eidenbenz 12ETH Zurich – Distributed Computing Group Raphael Eidenbenz Multi-Core Architecture

13. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 13 The Multicore Revolution

14. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 14 Transactional Memory explicit locks Which transaction shall I abort?? transactions Timestamp, Polite, Karma, Polka, Randomized,...

15. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 15 Transactional Memory is a Game –Players = programmers –Strategy space = placing of transactions –Their goal: fast execution –Social goal: maximize system throughput „My thread is the fastest!“

16. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 16 Good Programming incRingCounters(Node start){ var cur = start; transaction{ repeat{ cur.doSomething(); cur = cur.next; } until(cur==start) }} incRingCountersGP(Node start){ var cur = start; repeat{ transaction{cur.doSomething();} cur = cur.next; until(cur==start) }} long transactions vs short transactions R1R1 R3R3 t R2R2 RsRs R1R1 R3R3 t R2R2 RsRs

17. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 17 Good Programming Incentives A CM is GPI compatible iff it –punishes unnecessary locking –and rewards partitioning.

18. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 18 Quasi Priority Accumulating CM R1R1 R3R3 t R2R2 RsRs R1R1 R3R3 t R2R2 RsRs Thm : Timestamp is not GPI compatible.

19. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 19 Not priority based –„Choose random winner“ Proof Intuition –Unnecessary Locks: stupid because only risk conflict (no priority gain) –Partitioning: T i2 Randomized CM TiTi T i1 Lemma : Randomized CM is GPI compatible. T i2 TiTi T i1

20. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 20 Not priority based –„Choose random winner“ Proof Intuition –Unnecessary Locks: stupid because only risk conflict (no priority gain) –Partitioning: Randomized CM Lemma : Randomized CM is GPI compatible. TiTi T i1 T i2 TiTi

21. throughput collaborators (updates/s) Karma Polka Timestamp throughput collaborators (updates/s) Randomized throughput collaborators (updates/s) throughput selfish (updates/s)

22. ETH Zurich – Distributed Computing Group Raphael Eidenbenz 22ETH Zurich – Distributed Computing Group Raphael Eidenbenz Peer-to-Peer Computing

23. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 23 Peer-to-Peer File Sharing History

24. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 24 Cyclic Tit-for-Tat Trading

25. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 25 Cyclic Tit-for-Tat Trading

26. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 26 BitTorrent: Downloads per Peer

27. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 27 Cross-Swarm Cycles in BitTorrent

28. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 28 Evaluation

29. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 29 Evaluation Results

30. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 30 Cyclic Trading Protocol CYCT4T sourceviadist … inTable id … outTable

31. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 31 Cyclic Trading Protocol CYCT4T

32. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 32 Established Equilibrium utility n

33. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 33 BitThief: Smooth Transition utility n

34. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 34 BitThief: Smooth Transition utility n

35. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 35 Steganographic Handshake in BitThief BitThief is a BitTorrent client that –Free rides with BitTorrent clients [1], and –Trades tit-for-tat (T4T) with other BitThiefs [2] Block request sequence Hybrid approach using PEX –Order of peer addresses –Forged peer address [1] Locher et al., Free Riding in Bittorrent is Cheap, HotNets 2006 [2] Locher et al., Rescuing Tit-for-Tat with Source Coding, P2P 2007

36. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 36 ? Steganographic Handshake

37. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 37 ? Steganographic Handshake

38. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 38 Steganographic Channels P2P File sharing –Block request sequence –Block subset selection Timing Bandwidth Ports

39. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 39 Encoding Bits Into a Permutation

40. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 40 Hidden Broadcast Send a secret message to all conspirers n c n-c

41. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 41 Steganographic Broadcast Send a message to all conspirers Bittorrent-like p2p file sharing system k

42. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 42 Efficient Broadcast Lemma

43. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 43 Efficient Broadcast Lemma Algorithm

44. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 44 Proof of Theorem 10.1

45. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 45 Stronger Authority Models

46. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 46 Broadcast under Stochastic Monitoring

47. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 47 Broadcast under Stochastic Monitoring

48. ETH Zurich – Distributed Computing Group Raphael Eidenbenz, PhD Thesis 48 Conclusion tt

49. Thank You! Questions & Comments? TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AAAA A A A