---
title: "e. Download, compile and run the OSU Benchmark"
date: 2020-05-12T13:27:03Z
weight : 40
tags : ["tutorial", "EFA", "ec2", "OSU", "MPI", "Benchmark", "compile"]
---



In this section, you will download, compile and run a common MPI benchmarks from [Ohio State University (OSU) ](http://mvapich.cse.ohio-state.edu/benchmarks/)  .


#### Download and Compile the OSU Benchmarks

You can run the script below on the Master node of your ParallelCluster in the home directory

```bash
cd ~

cat > compile-osu.sh << EOF
#!/bin/bash

module load intelmpi

wget http://mvapich.cse.ohio-state.edu/download/mvapich/osu-micro-benchmarks-5.6.2.tar.gz
tar zxvf ./osu-micro-benchmarks-5.6.2.tar.gz
cd osu-micro-benchmarks-5.6.2/
./configure CC=mpicc CXX=mpicxx
 make -j 4
EOF

sh ./compile-osu.sh
```

Verify that the OSU-Benchmark is installed correctly

```bash
ll ~/osu-micro-benchmarks-5.6.2/mpi/pt2pt/osu_latency
```

#### Submit OSU Latency benchmark

Create your job submission script for *OSU Latency* and use **sbatch** to submit your job:

```bash
cat > osu_latency.sbatch << EOF
#!/bin/bash
#SBATCH --job-name=osu-latency-job
#SBATCH --ntasks=2 --nodes=2
#SBATCH --output=osu_latency.out

module load intelmpi
srun --mpi=pmi2 ~/osu-micro-benchmarks-5.6.2/mpi/pt2pt/osu_latency
EOF

sbatch osu_latency.sbatch
watch squeue
```

You have to wait a couple of minutes for your compute instances to come up, once you see the job go from **PD** pending to **R** running state, you know the instances are up. Type **Ctrl-C** to exit squeue at any point.

After the job has completed, find the output in `cat ~/osu_latency.out` . You will see something like:

```bash
$ cat ~/osu_latency.out
Loading intelmpi version 2021.4.0
# OSU MPI Latency Test v5.6.2
# Size          Latency (us)
0                      15.64
1                      15.63
2                      15.64
4                      15.63
8                      15.61
16                     15.62
32                     15.65
64                     15.69
128                    15.73
256                    15.77
512                    15.88
1024                   16.03
2048                   16.34
4096                   17.72
8192                   19.68
16384                  21.15
32768                  23.21
65536                  26.75
131072                 92.06
262144                 87.05
524288                153.99
1048576               286.83
2097152               552.51
4194304              1050.22
```

If EFA is configured correctly and you are running within a Cluster Placement Group, the latency between two EC2 instances will be ~15μs (Microsecond)
Running the same benchmark on two non-EFA enabled instances will show around ~25μs (Microsecond), much hihger values if case not running on a Cluster Placement Group.


#### Submit OSU Bandwidth benchmark

Another benchmark you might want to run is the *OSU Bandwidth*.

```bash
cat > osu_bw.sbatch << EOF
#!/bin/bash
#SBATCH --job-name=osu-bw-job
#SBATCH --ntasks=192 --nodes=2
#SBATCH --output=osu_bw.out

module load intelmpi
srun --mpi=pmi2 ~/osu-micro-benchmarks-5.6.2/mpi/pt2pt/osu_mbw_mr
EOF

sbatch osu_bw.sbatch
watch squeue
```

Below you can find an example output

```bash
[ec2-user@ip-10-0-1-178 shared]$ cat osu_bw.out
# OSU MPI Multiple Bandwidth / Message Rate Test v5.6.2
# [ pairs: 36 ] [ window size: 64 ]
# Size                  MB/s        Messages/s
1                       3.55        3553090.50
2                      12.76        6381876.74
4                      26.08        6519105.86
8                      50.34        6292207.14
16                     99.34        6208718.43
32                    192.53        6016617.21
64                    379.45        5928951.59
128                   744.38        5815464.56
256                  1460.41        5704732.62
512                  2820.96        5509684.33
1024                 5690.06        5556695.80
2048                 9512.98        4645008.26
4096                11519.99        2812496.73
8192                11996.54        1464421.42
16384               11869.56         724460.26
32768               11861.97         361998.56
65536               11785.50         179832.45
131072              11917.45          90922.97
262144              12038.01          45921.37
524288              12188.34          23247.41
1048576             12156.93          11593.75
2097152             12113.78           5776.30
```

In the above example, once we reached a message size of about 4k, we acheived a multi-pair bandwidth of 12k MBps or 96.9 Gbps, roughly the 100Gbps bandwidth availible on **hpc6a** instances.