Houdini 22.0 Nodes TOP nodes

Service Scheduler TOP node

Controls the scheduling of service work items.

Since 22.0

By default, PDG automatically runs PDG service work items using an interal scheduler. You can use this scheduler node to manually control the behavior of service work items. For example, this node can limit the number of work items that can cook simultaneously in an Invoke node.

To use an instance of this scheduler to control in-process work items, you must specify this scheduler as the TOP Scheduler Override on the node to which the work items belong. Otherwise, that node would continue to use the default service scheduling logic.

Parameters

Scheduler

The global parameters for all work items using this scheduler.

Scheduling

Max Work Items

Determines the maximum number of work items that can be scheduled at the same time by this scheduler. By default, the Pool Size of the service itself determines the maximum number of work items that can run using that service.

Use Service Defaults

Schedule work items based on the number of service clients in the service associated with the work items

Custom Count

Specifies a custom limit for the number of concurret work items run by this scheduler.

Tick Period

Sets the minimum time (in seconds) between calls to the onTick callback.

Max Items per Tick

Sets the maximum number of ready item onSchedule callbacks between ticks.

Paths

Working Directory

Specifies the relative directory where the work generates intermediate files and output. The intermediate files are placed in a subdirectory. For the Local Scheduler or HQueue, typically $HIP is used. For other schedulers, this should be a relative directory to Local Shared Root Path and Remote Shared Root Path; this path is then appended to these root paths.

Validate Outputs when Recooking

When on, PDG validates the output files of the scheduler’s cooked work items when the graph is recooked to see if the files still exist on disk. Work items that are missing output files are then automatically dirtied and cooked again. If any work items are dirtied by parameter changes, then their cache files are also automatically invalidated. Validate Outputs When Recooking is on by default.

Check Expected Outputs on Disk

When on, PDG looks for any unexpected outputs (for example, like outputs that can result from custom output handling internal logic) that were not explicitly reported when the scheduler’s work items finished cooking. This check occurs immediately after the scheduler marks work items as cooked, and expected outputs that were reported normally are not checked. If PDG finds any files that are different from the expected outputs, then they are automatically added as real output files.

Temp Directory

Location

Determines where the local temporary files are written to. Files that are written to this location are needed for the PDG cook, but are not typically the end product and can be removed when the cook completes.

For example, log files and python scripts are some of the files that are usually written during the cook.

Working Directory

Use pdgtemp subdirectory specified in the Working Directory field.

Houdini Temp

Use pdgtemp subdirectory of $HOUDINI_TEMP_DIR.

Custom

Use the custom directory specified by in the Custom field.

Append PID

When on, a subdirectory is added to the location specified by the Location parameter and is named after the value of your Houdini session’s PID (Process Identifier). The PID is typically a 3-5 digit number.

This is necessary when multiple sessions of Houdini are cooking TOP graphs at the same time.

Custom

The full path to the custom temporary directory.

This parameter is only available when Directory Location is set to Custom.

Delete Temp Dir

Determines when PDG should automatically delete the temporary file directory associated with the scheduler.

Never

PDG never automatically deletes the temp file directory.

When Scheduler is Deleted

PDG automatically deletes the temp file directory when the scheduler is deleted or when Houdini is closed.

When Cook Completes

PDG automatically deletes the temp file directory each time a cook completes.

Job Parms

The job-specific parameters.

Tip

You can override these parameters per node with the Edit Parameter Interface. For more information, see Scheduler Job Parms / Properties.

Cooking

Single

When on, the scheduler is only be able to run one work item at a time. Work items in other nodes where Single is turned off are still able to run concurrently.

Load as Native Work Item

When on, the scheduler forces service clients to load work item data as a native pdg.WorkItem instead of as a pure Python stub object, regardless of the node-specific settings.

Apply Wedges

When on, the scheduler indicates to service clients that they should apply wedge attributes to the scene before cooking.

Error Handling

When an service work item encounters an error while cooking, it is marked as failed by default. These parameters allow you to change that behavior.

On Task Failure

Determines what happens when a work item fails.

Report Error

The work item fails and an error message is added to the scheduler.

Report Warning

The work item succeeds and a warning message is added to the scheduler.

Retry Task

The work item restarts immediately according to the current Maximum Retries and Retry Count Attribute parameter settings.

Ignore

The work item succeeds and no message is issued.

Maximum Retries

Sets the maximum number of times the work item will be restarted.

This parameter is only available when On Task Failure is set to Retry Task.

Retry Count Attribute

When on, adds an int attribute set to the number of times the task was restarted.

See also

TOP nodes