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Deadlock Detection in
Distributed Systems
Dr. Davarpanah
Research:
Kaywan Zayer
Reza Ramezani
Mohammad Khosravi
Deadlock
• Introduction
• Strategies to handle deadlock
– Ostrich algorithm (ignore it)
– Detection (let occur, detect, re...
Deadlock Detection
• Centralized
– Single point of failure
– bottleneck
• Distributed
– Soojung Lee
– Monjurul Alom et al
...
Introduction
• Process dependency
– wait-for graph (WFG)
• Request model
– AND
– OR
– p out-of q
• Communication model
– J...
Soojung Lee
• Dependency Model
– Reduced wait-for graph (RWFG)
– knot
• Request model
– OR
• Blocked process can participa...
Message
• Probe
– Distributed Spanning Tree (DST)
– Path-string decoding
– Unique id
• Reply
– ACTIVE
– REPORT
Example
(i) WFG (ii) DST
Example
(iii) RWFG after receive ACTIVE
(iv) RWFG after receive REPORT
(v) Final RWFG
Monjurul Alom et al
• Distributed Database System
• Dependency model
– Transaction wait-for graph (TWFG)
• Request model
–...
Algorithm Scheme
• LTS for each local site
• DTS for global resource transaction
communication
• Priority Id for each tran...
Example
TWFG
Example
LTS2 : {3->5, 5->6, 6->3}
{7->10, 10->9, 9->7}
{10->9, 9->11, 11->10}
LTS3 :
Example
Example
DTS1 : {4->3, 3->3, 3->4, 4->4} DTS2 : {6->4, 4->8, 8->7, 7->6}
Detected deadlock, breaking it
Final TWFG
Farajzadeh et al
• History-based edge chasing
– Probe message
• Request model
– p out-of q
• Messages
– Probe
– Clean-up
–...
Algorithm
• Receive probe
– In memory and id = received id
• Prefix of received route-string
– deadlock
• Otherwise
– Save...
Comparison
• First an third algorithm
– Both use probe messages
– Build WFG
– Different in message number, delay, message ...
Deadlock detection in distributed systems
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Deadlock detection in distributed systems

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Deadlock detection in distributed systems

  1. 1. Deadlock Detection in Distributed Systems Dr. Davarpanah Research: Kaywan Zayer Reza Ramezani Mohammad Khosravi
  2. 2. Deadlock • Introduction • Strategies to handle deadlock – Ostrich algorithm (ignore it) – Detection (let occur, detect, recover) – Prevention (make it impossible to occur) – Avoidance (careful resource allocation)
  3. 3. Deadlock Detection • Centralized – Single point of failure – bottleneck • Distributed – Soojung Lee – Monjurul Alom et al – Farajzadeh et al
  4. 4. Introduction • Process dependency – wait-for graph (WFG) • Request model – AND – OR – p out-of q • Communication model – Just message communication – Bounded delay, reliable protocol
  5. 5. Soojung Lee • Dependency Model – Reduced wait-for graph (RWFG) – knot • Request model – OR • Blocked process can participate in deadlock detection algorithm
  6. 6. Message • Probe – Distributed Spanning Tree (DST) – Path-string decoding – Unique id • Reply – ACTIVE – REPORT
  7. 7. Example (i) WFG (ii) DST
  8. 8. Example (iii) RWFG after receive ACTIVE (iv) RWFG after receive REPORT (v) Final RWFG
  9. 9. Monjurul Alom et al • Distributed Database System • Dependency model – Transaction wait-for graph (TWFG) • Request model – AND • Linear Transaction Structure (LTS) • Distributed Transaction Structure (DTS)
  10. 10. Algorithm Scheme • LTS for each local site • DTS for global resource transaction communication • Priority Id for each transaction in each of the sites • The local and global cycles • Abort of the victim transaction based on the cycles
  11. 11. Example TWFG
  12. 12. Example LTS2 : {3->5, 5->6, 6->3} {7->10, 10->9, 9->7} {10->9, 9->11, 11->10} LTS3 :
  13. 13. Example
  14. 14. Example DTS1 : {4->3, 3->3, 3->4, 4->4} DTS2 : {6->4, 4->8, 8->7, 7->6}
  15. 15. Detected deadlock, breaking it
  16. 16. Final TWFG
  17. 17. Farajzadeh et al • History-based edge chasing – Probe message • Request model – p out-of q • Messages – Probe – Clean-up – Ok – Deny
  18. 18. Algorithm • Receive probe – In memory and id = received id • Prefix of received route-string – deadlock • Otherwise – Save probe with smaller path-string and propagate received probe • Deadlock – Initiator • Clean-up and suicide – Otherwise • Request permission for suicide
  19. 19. Comparison • First an third algorithm – Both use probe messages – Build WFG – Different in message number, delay, message size and resolution scheme Sujung lee farajzadeh Number of message 2e <=e Message size d+2 <=O(d) delay O(dlogn) n resolutaion yes Yes, 2 message e : number of edge in WFG, n : number of node, d : diameter of WFG

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