Architecture Modeling - SPES 2020

Architecture Modeling
expressed by the concept ProcessingResource. The SchedulingPolicy concept allows
to specify the strategy of the scheduler, e. g. fixed-priority based. The SchedulerSlots,
which receive a fraction of the resource, aggregate the concept SchedParameterSpec, that
specifies parameters used by a scheduler to run its strategy. Such parameters are for example
the definition of a priority.
RichComponent
Resource
+ isActive: Boolean
+ isProtected: Boolean
+ resMult: int [0..1] = 1
+required
SchedulerPort
SchedulerRPort +required
ConcurrencyResource ProcessingResource SchedulerSlot
0..*
+ isPreem ptible: Boolean = true
Variable
SchedParameterSpec
+provided
SchedulerPort
SchedulerPPort +provided
0..1
+required 1
+provided 0..*
0..*
+schedParameters 1
1..*
Scheduler
+ isPreemptible: Boolean = true
+policy 1
+schedule
1
TextuallyRepresentedElement
Expression
+scheduleLength 0..1
SchedulingPolicy
+ otherSchedPolicy: String [0..1]
+ policy: SchedPolicyKind = FixedPriority
Figure 3.11: Meta-model integration of the concept Scheduler
The concept, which actually uses the fraction of the ProcessingResource, is a
ConcurrencyResource or specializations thereof. If some schedule was determined offline,
it can be directly specified by means of an Expression in the role schedule. This
overrides whatever was specified in the SchedulingPolicy.
The relation of the concepts Scheduler, SchedulerSlot and
ConcurrencyResource is modeled by the special ports SchedulerPPort and
SchedulerRPort. That ports must be typed by a PortSpecification, which is
conformant to the concept SchedulerPortSpec (see Figure 3.12). This specification
comprises five flows, that are referenced in the following roles:
activateEvent is a flow of kind event. The direction is always in. This event
denotes the request for the activation of a ConcurrencyResource. The
ConcurrencyResource thus notifies its need to access the capacity of a
ProcessingResource.
startEvent is a flow of kind event. The direction is always out. This event denotes the grant
of some Scheduler upon a previously received request (the activateEvent).
finEvent is a flow of kind event. The direction is always in. This event denotes the release
of the capacity of the ProcessingResource by the ConcurrencyResource. It
is triggered, when the ConcurrencyResource has finished its computation or communication.
suspendEvent is a flow of kind event. The direction is always out. The referenced flow
shall be triggered by some Scheduler or forwarded by some SchedulerSlot, when
access to the processing capacities of a scheduled resource has been granted before, but
shall now be revoked in favour of another SchedulerSlot. This reference to a flow is
only needed, if preemption can occur.
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