Experience and Expertise of Designing SDN MPI_Bcast

Khureltulga Dashdavaa, Susumu Date, Hiroaki Yamanaka, Eiji Kawai, Yasuhiro Watashiba,

Kohei Ichikawa, Hirotake Abe, Shinji Shimojo

1

•Background and Problem

•Software-Defined Network

•Research goal

•Proposed method: SDN_MPI_Bcast

•Evaluation

•Conclusion

2

Outline

N : Computing nodeP0, P1, P2, P3 : Running process

• MPI is playing great role in parallel

programming.• However, MPI implementation is not

optimized for common network hardware, such as Gigabit Ethernet.

3

Network

N N N N N

P2 P3 P1P0

Example: MPI_Bcast (basic collective communication)

Background and Problem

Main reason is that network has “static” resource, and cannot be controlled “dynamically”.

➡Collective communication uses multiple unicast-based communication.

4

Emergence of Software-Defined Network

Controller part(how to deal with packets)

Controller part(how to deal with packets)

3

1

1 1

2

2

4Switch

Switch

5 6 32 4Switch

5 6

Traditional Network

Software-Defined Network (SDN) : a new concept of network technology

5

Software-Defined Network

Emergence of Software-Defined Network

Network Controller

3

1

1 1

2

2

4SDN Switch

SDN Switch

Input PacketIn : 2Out : 1, 4, 6

5 6 32 4SDN Switch

5 6

➡ Network controller can control network “dynamically”.

Software-Defined Network (SDN) : a new concept of network technology

Example:• Controls out

going port or ports of incoming packet on switches.

- In SDN, controller parts decoupled from devices (switches) and centralized to one place.

• Integrate “dynamic” controller ability of SDN into MPI in order to overturn the assumption that network is “static” resource.

6

•Reduce execution time of MPI_Bcast using SDN.

Research goal

3

1

1 1

2

2

4SDN Switch

SDN Switch

Network Controller

5 6

N N N N N N N N N N

32 4SDN Switch

5 6

SDN MPI

3

1

1 1

2

2

4

7

SDN Switch

SDN Switch

Network controller

Data Data Data DataData Data Data

In ： 2Out ： 1, 4

In ： 1Out ： 2, 4

In ： 1Out ： 2

5 6

N

P0

An SDN feature that Network controller can choose outgoing ports of incoming packet on switches is adapted to MPI_Bcast as a duplication action.

Proposed Method: SDN_MPI_Bcast

N N N N

P2

N N N N N

P3 P1

32 4SDN Switch

5 6

A process sends data only once for broadcasting data in our method

3

1

2 4SDN Switch

5 6

8

Change process numbers•Data size ： 15.6 KiB

(constant)

• Execution time of SDN_MPI_Bcast and MPI_Bcast.

Experiment Result

Change process number

• Execution time on initialization.•

Install Duplication Rules.

• Introduced architecture of MPI_Bcast Leveraged Software-Defined Network.

•Our experiment result confirmed that SDN_MPI_Bcast is feasible.

• Future Works

•Stability and reliability of prototype implementation.

•Aim to SDN MPI.

9

Conclusion