This document will provide a simple example to get up and running with dimebox to perform a simple experimental setup of an MPI program.
To create your first experiment testbed, run dimebox init in the same directory as your executable.
dimebox init
This will create the directory structure for your experimental setup:
.
├── experiments
│ ├── jobs
│ ├── results
│ └── simple.yml
The jobs directory will store all of the generated job files and the results directory will store the output from your jobs' execution. Each experiment is defined by a YAML file (expfile) which gives various configuration options, such as the number of processor counts, commands to be run in each job and a list of parameters to perform an exhaustive study of. See expfile.md for more information.
In our example, our expfile is simple:
name: heat
desc: Heat equation for various processor counts
p: [1, 2, 4, 8, 16, 32]
cmds:
heat: ./heatNext, we want to generate the job files for this experiment:
dimebox generate -m rain experiments/simple.yml
In this example, we will generate files for our predefined machine named "rain," but we will see how to define machine configurations later.
This command will have generated job files in our jobs folder in a specific epoch. The epoch is just the datetime in which the experiment was generated.
.
├── jobs
│ └── 20160225-124457
│ ├── heat-16.job
│ ├── heat-1.job
│ ├── heat-2.job
│ ├── heat-32.job
│ ├── heat-4.job
│ ├── heat-8.job
│ ├── run.yml
│ └── vc.yml
├── results
└── simple.yml
We can next launch the jobs we just created
dimebox submit HEAD
Here, the keyword HEAD is a special epoch representing the last generated experiment. Our jobs should be submitted to the batch submission system and be queued for future processing.
All of the results files should be stored in the results directory for the given epoch. There will be a result file for every combination of processor count, optional argument and command specified in the expfile. In addition, each job will print its standard output and standard error to special directories in the epoch for diagnosing errors.
After some time, our jobs will have finished and populated the results directory:
.
├── results
│ └── 20160225-124457
│ ├── heat-1
│ ├── heat-16
│ ├── heat-2
│ ├── heat-32
│ ├── heat-4
│ ├── heat-8
│ ├── stderr
│ │ ├── heat-1.131693.sdb.err
│ │ ├── heat-16.131694.sdb.err
│ │ ├── heat-2.131695.sdb.err
│ │ ├── heat-32.131696.sdb.err
│ │ ├── heat-4.131697.sdb.err
│ │ └── heat-8.131698.sdb.err
│ └── stdout
│ ├── heat-1.131693.sdb.out
│ ├── heat-16.131694.sdb.out
│ ├── heat-2.131695.sdb.out
│ ├── heat-32.131696.sdb.out
│ ├── heat-4.131697.sdb.out
│ └── heat-8.131698.sdb.out
Note It's possible to submit jobs in a way that only k jobs are considered for scheduling at a time. Use
dimebox submit --stagger --batch=kto enable this feature.
Keeping track of your experiments is one of the main benefits of using dimebox. Using the summary tool, it is easy to tell at a glance what has run and gives some context to your experiments:
dimebox summary
This will print a list of your experiments along with a small overview for each, including when it was generated, a description of the experiment, how many results are expected, how many were found and how many failed.
┌─────────────────┬───────┬───────┬───────┬─────────────────────────────────────────────┐
│ Epoch │ # │ files │ fail │ Description │
│ 20160227-113909 │ 4 │ 0 │ 0 │ Changing initial condition to 98. │
│ 20160225-125008 │ 4 │ 4 │ 4 │ Introducing a bug for test purposes │
│ 20160225-124722 │ 1 │ 1 │ 0 │ Only 128 processors │
│ 20160225-124457 │ 6 │ 6 │ 0 │ Heat equation for various processor counts │
└─────────────────┴───────┴───────┴───────┴─────────────────────────────────────────────┘
In addition, summarizing an individual epoch will provide the YAML file that was used to generate the jobs, giving you a look into the parameters that were used to run the experiments. It will also provide a random job to examine what was actually run, along with any version control information for reproducibility.
$ dimebox summary HEAD
Description: Changing initial condition to 98.
Epoch: 20160227-113909
Expected: 4
Files: 0
Failed: 0
Experimental setup:
name: heat
desc: Changing initial condition to 98.
p: [1, 2, 4, 128]
cmds: {heat: ./heat}
Random job: /mnt/lustre/lus0/afidel/testbed/experiments/jobs/20160227-113909/heat-2.job
#PBS -l mppwidth=2
#PBS -l mppnppn=32
#PBS -l walltime=00:30:00
#PBS -N heat-2
#PBS -e experiments/results/20160227-113909/stderr/heat-2.$PBS_JOBID.err
#PBS -o experiments/results/20160227-113909/stdout/heat-2.$PBS_JOBID.out
#PBS -V
MPIRUN="aprun -n 2"
cd /mnt/lustre/lus0/afidel/testbed
$MPIRUN ./heat &> experiments/results/20160227-113909/heat-2
Version control: git
commit: 4b8d026af9f84b1cac83f9cc0e78f709bb2c3d90
remotes: origin [email protected]:adamfidel/heat.git (fetch)
origin [email protected]:adamfidel/heat.git (push)
# On branch master
# Changes not staged for commit:
# (use "git add <file>..." to update what will be committed)
# (use "git checkout -- <file>..." to discard changes in working directory)
#
# modified: heat_mpi.c
#
# Untracked files:
# (use "git add <file>..." to include in what will be committed)
#
# experiments/
# heat
no changes added to commit (use "git add" and/or "git commit -a")
diff --git a/heat_mpi.c b/heat_mpi.c
index 6349c1d..fda35a5 100644
--- a/heat_mpi.c
+++ b/heat_mpi.c
@@ -444,7 +444,7 @@ double initial_condition ( double x, double time )
{
double value;
- value = 95.0;
+ value = 98.0;
return value;
}
Note: In the future, the binary itself will be included for true reproducibility.
In addition, dimebox can be used to parse the results for experiments into a standard row-oriented format with the dimebox parse command.
See parsing.md for more information.
The previous example was fairly straightforward, but it is possible to create an experiment set that contains a large amount of parameter exploration:
name: complex
desc: Testing an exhaustive study of parameters
p: [1, 2, 4, 8, 16, 32, 64, 128, 256, 512]
optargs:
tau: [1, 16, 64, 256, 4096]
k: [0, 1, 2, 4, 8, 16, 32]
r: [0.0, 0.2, 0.4, 0.8, 1.0]
cmds:
stats: ./stats 1048576 4 $r $tau $k 1 0
perf: ./perf 1048576 4 $r $tau $k 1 0
In this example, we have a large amount of parameters that we would like to test. There are 10 processor counts, three optional arguments (two of which have 5 choices and one that has 7 choices) and two commands to run. This gives a total of 3500 configurations. Imagine having to manage the job creation, submission and summarization for this experiment alone!
Sometimes, a program writes output or temporary files to the directory in which the program is run. When multiple jobs with the same program execute concurrently, interference will result in incorrect behavior.
It is possible to set up seperate isolated workspaces for each job using the workspace field in an expfile. Consider the following experiment:
name: isolated_jobs
p: [1, 2, 4, 8, 16, 32]
workspace:
links: [myexe]
cmds:
foo: ./myexeWhen using dimebox generate, separate directories will be created in experiments/workspaces/$epoch/$jobname. In each directory, symbolic links will be created for executables listed in the links field, along with a symbolic link to the top-level experiments directory for output to be correctly written. When each job is run, the first thing it will do is change directory to its own workspace and execute the program in isolation.