Ping-Pong Latency Test With Java Open-MPI Bindings and Java TCP/IP Sockets

This repository is used for measuring the Java Open-MPI bindings vs Java TCP socket latencies for a network of distributed processes. Basically, it performs some ping-pong tests between a number of processes.

A basic test consists of the following flow:

1. A pinger node is created.
2. Other nodes in the system play the role of ponger.
3. Pinger sends ping request to all the pongers.
4. The time taken from the first ping request to the last pong received is recorded.
5. Steps (3) and (4) is repeated inside a loop.
6. Results from step 5 are recorded and their average is calculated.

Software Dependencies

It is important the followings are available in your system:

• Open-MPI with Java bindings are set-up,
• Java 8 or above,
• Maven.

Running Java Open-MPI Latency Tests

Edit the mpi.sh script for your needs and run it like:

$ ./mpi.sh

Running Java TCP Socket Tests

The Java TCP sockets use the mpirun for running the Java sockets in parallel. This is the main method used for testing/ debugging the application. To use this approach use the socket.sh script:

$ ./socket.sh

You can also use the class SocketMainSingleJVM.java to execute the tests with an IDE of your choice which makes it easier to debug the entire application.

OSU Point-to-Point Latency Tests

The repository also includes the Java converted point-to-point osu_latency tests both for Open-MPI and Java TCP sockets. Use the following scripts to run these tests:

$ ./osu_latency_mpi.sh
$ ./osu_latency_socket.sh

Results

Detailed description of the work and the testing procedure can be read in the following paper: paper.pdf. I encourage you to read the paper first before diving in the following sections.

The final data collected can be found in ./slurm/data/all_combined.ods file. Using an office program of your choice to open it.

Data Collection

A script located in ./slurm/scripts/work.sh is used to run the tests on the University of Tartu's HPC Rocket cluster.

The test results produced in csv files are in the following format.

Ping-Pong Tests

The format and a sample of the csv files for the Ping-Pong Roundtrip latency test is as follows:

Test Name	Test Phase	Num Iterations	Leader Node Name	Timestamp	Time	Latency (ms)
pingAllIntermediate	full-load	500	p0g31	1526646657332	15:30:57.332	5

The format and a sample of the csv files for the Ping-Pong Point-to-Point latency test is as follows:

Test Name	Test Phase	Num Iterations	Leader Node Name	Timestamp	Time	Latency (ms)
pingSingle	N/A	-1	p0g31	1526646655664	15:30:55.664	3

OSU Latency Tests

A single OSU Latency test result csv file is of the following form (1 line provided for a sample):

Size(bytes)	latency (us)
2	240

Data Processing

Ping-Pong Tests

The data is processed using R. Scripts located in ./slurm/data/ping-pong-tests/process/ folder are used to process the data. Basically, the ./slurm/data/ping-pong-tests/process/run.sh script was submitted to the job scheduler of the cluster. Following is the procedure:

1. After collecting the data, all the relevant latency results are grouped together based on the number of nodes.
2. Outliers are removed.
3. The mean of the latency values are calculated and recorded.

OSU Latency Tests

No special arrangement is done for the OSU latency tests since these are standard. The collected data was just printed in their corresponding csv file.