Workload

A workload defines the tasks that are submitted to the data center, when they are submitted, and how much CPU, GPU and memory they need over time. In OpenDC2, a workload is always read from a workload trace.

Field	Type	Default	Description
pathToFile	string	required	The directory of the workload trace.
type	string	required	The kind of workload. The only kind is ComputeWorkload.
sampleFraction	number	1.0	Runs a random sample of the tasks that together have this fraction of the total work of the trace.
submissionTime	string	unchanged	Moves the workload in time so that the first task is submitted at this time, such as "2024-01-01T00:00:00" (UTC).
deferAll	boolean	false	Makes every task deferrable, with a deadline of its submission time plus three times its duration.
scalingPolicy	scaling policy	NoDelay	What happens when a task gets less than it demands.

{
    "pathToFile": "traces/bitbrains-small",
    "type": "ComputeWorkload"
}

Scaling policies

Policy	Behaviour
NoDelay	The task keeps its duration. Demand that is not met is lost. This is the default.
Perfect	The task runs longer, so that all of its work is eventually done.

Workload traces

A workload trace is a directory with two Parquet files: tasks.parquet describes each task, and fragments.parquet describes the demand of each task over time.

tasks.parquet

Column	Type	Required	Description
id	int32	yes	Identifier of the task.
name	string	no	Name of the task.
submission_time	timestamp (milliseconds)	yes	When the task is submitted.
duration	int64	yes	How long the task runs, in milliseconds.
cpu_count	int32	yes	The number of CPU cores the task needs.
cpu_capacity	double	yes	The CPU capacity the task needs, in MHz.
mem_capacity	int64	yes	The memory the task needs, in MiB.
gpu_count	int32	no	The number of GPU cores the task needs.
gpu_capacity	double	no	The GPU capacity the task needs, in MHz.
parents	list of int32	no	The tasks that must finish before this task can start.
children	list of int32	no	The tasks that depend on this task.
deferrable	boolean	no	Whether a time-shifting scheduler may delay the task.
deadline	int64	no	The latest time the task may finish, in milliseconds since the Unix epoch.

fragments.parquet

Each row is one fragment, during which the demand of a task is constant. The fragments of a task are in order.

Column	Type	Required	Description
id	int32	yes	Identifier of the task.
duration	int64	yes	How long the fragment lasts, in milliseconds.
cpu_usage	double	yes	The CPU demand during the fragment, in MHz.
gpu_usage	double	no	The GPU demand during the fragment, in MHz.