Parallel Jobs


FireMarshal is capable of running multiple jobs in parallel. To understand how this feature works, let’s use the parallelJobs.yaml workload as an example.

  "name" : "parallelJobs",
  "base" : "br-base.json",
  "jobs" : [
      "name" : "j0"
      "name" : "j1"

Based on br-base.json, this simple workload defines a root workload (implicitly) and two jobs - j0 and j1.

Note that within a single invocation of the marshal command, the names of the root workloads must be unique. Similarly, within a single workload, jobs must have unique names.

We can build this workload and launch its root as follows:

./marshal build example-workloads/parallelJobs.yaml
./marshal launch example-workloads/parallelJobs.yaml

FireMarshal uses screen sessions to run workloads. Notice how the root workload, running buildroot emulated using QEMU, launches directly in your terminal. When a single workload is launched, FireMarshal attaches to its screen session by default.

The default login details for all workloads are:

buildroot login: root

Password: firesim

Once logged in, you can run commands in the terminal. To exit, use:


We can launch a single job j0 as follows:

./marshal launch --job j0 example-workloads/parallelJobs.yaml

The same login details and exit procedure apply.

Note that both the root and the job workloads can’t be launched at once.

Let us now launch both jobs in this workload using:

./marshal launch --all example-workloads/parallelJobs.yaml

FireMarshal uses separate screen sessions to run workloads in parallel. It exits only after all launched workloads have exited.

One can attach to a workload to interact with or observe it by opening a new terminal (with tmux for instance), using standard screen syntax, and the screen session identifiers listed in the output of the launch command.

For instance, attach to job j0, using:

screen -r parallelJobs-j0

To detach from inside the screen session, use ctrl-a then ctrl-d.

Similarly, attach to job j1, using:

screen -r parallelJobs-j1

Login (with the details provided above) and then use the poweroff command to shut job j1 down.

Now re-attach to job j0, using:

screen -r parallelJobs-j0

Login (with the details provided above) and then use the poweroff command to shut job j0 down.

FireMarshal also logs stdout and stderr to a uartlog file for each workload. These files can be found inside the corresponding workload output directory inside runOutputs. The path to this directory will be output by the launch command. For instance, a workload output directory for the launched parallelJobs workload would be called parallelJobs-launch-YYYY-MM-DD--HH-MM-SS-<HASH>.