yo-yo leader election lijie wang 6982704 1. using spin used to detect design error in applications;...
TRANSCRIPT
YO-YO Leader Election
Lijie Wang6982704
1
Using SPIN Used to detect design error in
applications; descriptions of distributed
algorithms.
2
YO-YO Algorithm Minimum finding
Leader(smallest id node) Consists two parts
Preprocessing Iterations
3
Basic Components Node
Id Neighbor
s
4
Edge Between nodes Voting through
Preprocessing Node
Exchange its id with neighbors
5
Edge Direction
Small->large (id)
DAG
6
Direction goes down
using different ico
7
Candidates Local minima
->source ->candidate
8
Preprocessing completed
Second part start…
Iteration Remove candidates
Leave the only one
9
Two phases YO- -YO
10
Source: ⊙->id-> out neighbors Internal: ->all in neighbors-> ⊙->min->out neighbors Sink: ->all in neighbors-> ⊙
All sink done -> YO- end…
11
-YO start… Sink: ⊙->Y ->min; ⊙-> N->others Internal: ->all out neighbors-> ⊙
Receive at least one N: ⊙->N-> all in neighbors Receive all Y: ⊙->Y->min; ⊙->N->others
Source: all out neighbors -> ⊙
Eliminate candidates
Receive at least one N No longer a candidate
How?...
12
Receive all Y Survives (this
time)
Reverse N-edge Receive at least one N
No longer a candidate Become sink or
internal
13
Modify DAG Flip the link
with N
With reversing Sink and internal not
become candidate
less candidate
Drag down the dead candidates
14
And start over…
YO- [2]
15
-YO [2]
16
Flip [2]
17
Termination?
18
Count the only one candidate Become the leader
Pruning
To reduce the message To detect termination
Only left one source
Additional mechanism
Pruning
19
Eliminate leaf
Eliminate redundant route
20Pruning [1]
21
Pruning [2]
22
Pruning more [2]
23
Pruning [3]
Complexity
24
Without pruning Each phase: 2 messages each link Number of phase: log (number of sources) Total: 2*m*log(s)
With pruning Though we do not know the exact number
of reduced message in each iteration. Surely, the communication cost will be less
remarkable Total: 2*
For the spin result
25
Fail to intall Ispin on the 64-bit system Try to use the Virtual Machine with a 32-
bit system
Ispin result will be show in the final report
THANK YOU