agent-based model simulation with twister bingjing zhang, [email protected]@indiana.edu...
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Agent-based Model Simulationwith Twister
Bingjing Zhang, [email protected]
Lilian Weng, [email protected]
B649 Term Project Presentation
Problem Statement
• Run the agent-based modeling (ABM)[1] simulation in parallel.
• Reason: Sequential iterations on a single machine are too slow
[1] E. Bonabeau. Agent-based modeling: Methods and techniques for simulating human systems.
Proceedings of the National Academy of Sciences, 99:7280–7287, 2002.
Experiment
• A model simulating Twitter mechanism:– Users are connected through the social network– Each user has a screen of messages from neighbors,
and a memory of topics he is interested in.– Users send messages chosen from screen or memory
C - capacity of the screen and memory.Pn - probability to introduce a new topic.Pr - probability to re-post a message from the screen.α - the priority of topics in the memory compared to the screen messages, and therefore the probability of posting about the memory topics is αPr.
ArchitectureDesign of the Application
Broadcasting on Twister
• Broadcasting– Chain Broadcasting– All-to-all Minimum-spanning Tree
Chain Broadcasting Protocolsend
get ack
send
Driver Daemon 0receive
handle data
send
Daemon 1
ack receive
handle data
send
ack
receive
handle data
get ack
ack receive
handle data
get ack
send
send
get ack
Daemon 2
receive
handle data
ack
receive
handle data
ack
ack
get ack
get ack
“Handle data” is done by spawning another thread
“Send” and “Receive” are done in a manner of “buffer by buffer”
MST broadcasting
Driver sends data portions to different nodes
MST Leaf Node
MST Root Node
Twister Driver
All-to-all-MST Broadcasting Protocal
MST Broadcasting Protocol
[3] Ernie Chan et, al. Collective Communication: Theory, Practice, and Experience. Concurrency and
Computation: Practice and Experience. 2007
Implementation: Model Classes
Implementation: TwisterMessagepublic void fromTwisterMessage(TwisterMessage message) throws SerializationException {
message.writeInt(a);…
}
public void toTwisterMessage(TwisterMessage message) throws SerializationException {
this.a = message.readInt();…
}
Results: Broadcasting Efficiency 80 PG nodes, 2 switches, 50 Iterations, Data Size(Each Iteration) 200KB ~ 200MB, Data
Size(Total) 1GB ~ 5GB
Results: Simulation Result Validation
Memory Length – number of topics in memoryTopic Popularity – number of distinct user who have used a certain topicTopic Prevalence – number of posts containing a certain topic
Thank you! Question?