org.apache.flink.runtime.jobmaster.slotpool

Class SlotSharingManager

java.lang.Object

org.apache.flink.runtime.jobmaster.slotpool.SlotSharingManager

public class SlotSharingManager
extends Object

Manager which is responsible for slot sharing. Slot sharing allows to run different tasks in the same slot and to realize co-location constraints.

The SlotSharingManager allows to create a hierarchy of SlotSharingManager.TaskSlot such that every SlotSharingManager.TaskSlot is uniquely identified by a SlotRequestId identifying the request for the TaskSlot and a AbstractID identifying the task or the co-location constraint running in this slot.

The SlotSharingManager.TaskSlot hierarchy is implemented by SlotSharingManager.MultiTaskSlot and SlotSharingManager.SingleTaskSlot. The former class represents inner nodes which can contain a number of other SlotSharingManager.TaskSlot and the latter class represents the leaf nodes. The hierarchy starts with a root SlotSharingManager.MultiTaskSlot which is a future SlotContext assigned. The SlotContext represents the allocated slot on the TaskExecutor in which all slots of this hierarchy run. A SlotSharingManager.MultiTaskSlot can be assigned multiple SlotSharingManager.SingleTaskSlot or SlotSharingManager.MultiTaskSlot if and only if the task slot does not yet contain another child with the same AbstractID identifying the actual task or the co-location constraint.

Normal slot sharing is represented by a root SlotSharingManager.MultiTaskSlot which contains a set of SlotSharingManager.SingleTaskSlot on the second layer. Each SlotSharingManager.SingleTaskSlot represents a different task.

Co-location constraints are modeled by adding a SlotSharingManager.MultiTaskSlot to the root node. The co-location constraint is uniquely identified by a AbstractID such that we cannot add a second co-located SlotSharingManager.MultiTaskSlot to the same root node. Now all co-located tasks will be added to co-located multi task slot.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	SlotSharingManager.MultiTaskSlot SlotSharingManager.TaskSlot implementation which can have multiple other task slots assigned as children.
class	SlotSharingManager.SingleTaskSlot SlotSharingManager.TaskSlot implementation which harbours a LogicalSlot.
static class	SlotSharingManager.TaskSlot Base class for all task slots.

Method Summary

Modifier and Type	Method and Description
boolean	contains(SlotRequestId slotRequestId)
Collection<SlotSharingManager.MultiTaskSlot>	getResolvedRootSlots() Returns a collection of all resolved root slots.
boolean	isEmpty()
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Detail

isEmpty

public boolean isEmpty()

contains

public boolean contains(SlotRequestId slotRequestId)

toString

public String toString()

Overrides:

toString in class Object

getResolvedRootSlots

@VisibleForTesting
public Collection<SlotSharingManager.MultiTaskSlot> getResolvedRootSlots()

Returns a collection of all resolved root slots.

Returns:

Collection of all resolved root slots