README.md

Introduction

This composition is a simple demonstration a EAR use with simulated OAR interaction. NAS Parallel Benchmarks are provided and compiled with gcc in MPI and OpenMP variants.

Main Steps

See main README for more information about setting.

Build

oarsub -I
cd regale-nixos-compose/ear
nxc build

Deploy

Nodes requirements: 4 nodes

export $(oarsub -l nodes=4,walltime=2:0 "$(nxc helper g5k_script) 2h" | grep OAR_JOB_ID)
nxc start -m ./OAR.$OAR_JOB_ID.stdout -W
nxc connect

Use

On node1 or node2

#
# On node1 or node2
#
# create a node file for MPI
yes node1  | head -n 16 > machines && yes node2  | head -n 16 >> machines
uniq machines > uniq_machines

# Set OAR variable and signal the start job to EAR
export OAR_JOB_ID=1
export OAR_USER=user1
oar-ejob 50001 newjob uniq_machines

# Launch cg.C.mpi with approriate LD_PRELOAD
# Note: TCP is used for communication
mpirun --hostfile machines  --mca btl tcp,self \
-x LD_PRELOAD=${EAR_INSTALL_PATH}/lib/libearld.so \
-x OAR_EAR_LOAD_MPI_VERSION=ompi \
-x OAR_EAR_LOADER_VERBOSE=4 \
-x OAR_STEP_NUM_NODES=2 \
-x OAR_JOB_ID=$OAR_JOB_ID \
-x OAR_STEP_ID=0 \
cg.C.mpi

# Signal the job end to EAR
oar-ejob 50001 endjob uniq_machines

# After some lapse of time
ereport
eacct

# On eardb Node
# to explore the database
mysql -D ear
select * from Jobs;
select * from Applications;
select * from Signatures;