Scheduling requirements

docs/software_requirements/index.sdoc

@@ -69,3 +69,6 @@ FILE: tracing.sdoc
 
 [DOCUMENT_FROM_FILE]
 FILE: condition_variables.sdoc
+
+[DOCUMENT_FROM_FILE]
+FILE: scheduling.sdoc

docs/software_requirements/scheduling.sdoc

@@ -0,0 +1,204 @@
+[DOCUMENT]
+TITLE: Scheduling
+REQ_PREFIX: ZEP-SRS-23-
+
+[GRAMMAR]
+IMPORT_FROM_FILE: software_requirements.sgra
+
+[TEXT]
+STATEMENT: >>>
+SPDX-License-Identifier: Apache-2.0
+<<<
+
+[SECTION]
+TITLE: Thread Scheduling Algorithm
+
+[REQUIREMENT]
+UID: ZEP-SRS-23-001
+STATUS: Active
+TYPE: Functional
+COMPONENT: Thread Scheduling
+TITLE: Priority-Based Selection
+STATEMENT: >>>
+The Zephyr RTOS shall select the highest priority ready thread as the current thread from the ready queue.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-SRS-23-002
+STATUS: Active
+TYPE: Functional
+COMPONENT: Scheduling
+TITLE: Earliest Deadline First Scheduling
+STATEMENT: >>>
+When earliest-deadline-first (EDF) scheduling is enabled, the Zephyr RTOS shall prioritize threads with equal static priority based on earliest deadline.
+<<<
+USER_STORY: >>>
+As a Zephyr RTOS user, I want to be able to schedule threads by earliest deadline first.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-SRS-23-003
+STATUS: Active
+TYPE: Non-Functional
+COMPONENT: Scheduling
+TITLE: Ready Queue Scalability
+STATEMENT: >>>
+The Zephyr RTOS shall support configurable ready queue implementations.
+<<<
+
+[/SECTION]
+
+[SECTION]
+TITLE: Reschedule Points
+
+[REQUIREMENT]
+UID: ZEP-SRS-23-004
+STATUS: Active
+TYPE: Functional
+COMPONENT: Scheduling
+TITLE: Mandatory Context Switch Triggers
+STATEMENT: >>>
+The Zephyr RTOS shall trigger rescheduling during: thread state transitions (→SUSPENDED/WAITING), ISR returns, explicit k_yield() calls, and time slice expiration.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-SRS-23-005
+STATUS: Active
+TYPE: Functional
+COMPONENT: Scheduling
+TITLE: Atomic Rescheduling
+STATEMENT: >>>
+The Zephyr RTOS shall perform rescheduling atomically at designated points to prevent partial state corruption during thread swaps.
+<<<
+
+[/SECTION]
+
+[SECTION]
+TITLE: Thread States and Priorities
+
+[REQUIREMENT]
+UID: ZEP-SRS-23-006
+STATUS: Active
+TYPE: Functional
+COMPONENT: Scheduling
+TITLE: Cooperative Thread Non-Preemption
+STATEMENT: >>>
+The Zephyr RTOS shall ensure Cooperative threads (negative priority) retain execution until explicitly yielding or entering unready state.
+<<<
+USER_STORY: >>>
+As a Zephyr RTOS user, I want to be able to configure thread prioritizes which cannot be preempted by other user threads.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-SRS-23-007
+STATUS: Active
+TYPE: Functional
+COMPONENT: Scheduling
+TITLE: Preemptive Thread Interruption
+STATEMENT: >>>
+The Zephyr RTOS shall allow Preemptive threads (≥0 priority) to be interrupted immediately by higher-priority ready threads.
+<<<
+USER_STORY: >>>
+As a Zephyr RTOS user, I want that the OS preempt running threads by a thread with higher priority.
+<<<
+
+[/SECTION]
+
+[SECTION]
+TITLE: Time Slicing
+
+[REQUIREMENT]
+UID: ZEP-SRS-23-008
+STATUS: Active
+TYPE: Functional
+COMPONENT: Scheduling
+TITLE: Cooperative Voluntary Yielding
+STATEMENT: >>>
+The Zephyr RTOS shall provide a mechanism for Cooperative threads to allow equal/higher priority threads to execute before resuming.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-SRS-23-009
+STATUS: Active
+TYPE: Functional
+COMPONENT: Scheduling
+TITLE: Preemptive Time Quantum
+STATEMENT: >>>
+The Zephyr RTOS shall ensure Preemptive threads relinquish CPU after a configurable time slice (system ticks) if equal-priority threads are ready.
+<<<
+
+[/SECTION]
+
+[SECTION]
+TITLE: Thread Management
+
+[REQUIREMENT]
+UID: ZEP-SRS-23-
+STATUS: Draft
+TYPE: Functional
+COMPONENT: Scheduling
+TITLE: Scheduling multiple threads
+STATEMENT: >>>
+The Zephyr RTOS shall provide an interface to schedule multiple threads.
+<<<
+RELATIONS:
+- TYPE: Parent
+  VALUE: ZEP-SYRS-16
+
+[REQUIREMENT]
+UID: ZEP-SRS-23-010
+STATUS: Active
+TYPE: Functional
+COMPONENT: Scheduling
+TITLE: Non-Preemptible Critical Sections
+STATEMENT: >>>
+The Zephyr RTOS shall provide a mechanism to treat preemptive threads as cooperative until a unlock function is called.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-SRS-23-011
+STATUS: Active
+TYPE: Functional
+COMPONENT: Scheduling
+TITLE: Thread Sleeping
+STATEMENT: >>>
+The Zephyr RTOS shall provide a mechanism to delay thread execution within ±1 tick of requested duration.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-SRS-23-011
+STATUS: Active
+TYPE: Functional
+COMPONENT: Scheduling
+TITLE: Thread Waking
+STATEMENT: >>>
+The Zephyr RTOS shall provide a mechanism to for a thread to wake another thread. Note: A wakeup can be attempted on a thread that is already awake - this has no effect.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-SRS-23-012
+STATUS: Active
+TYPE: Functional
+COMPONENT: Scheduling
+TITLE: Busy Wait Non-Relinquishing
+STATEMENT: >>>
+The Zephyr RTOS shall provide a mechanism to perform a busy wait where the Zephyr RTOS will not yield CPU or trigger rescheduling during delay.
+<<<
+
+[/SECTION]
+
+[SECTION]
+TITLE: SMP Considerations
+
+[REQUIREMENT]
+UID: ZEP-SRS-23-015
+STATUS: Active
+TYPE: Functional
+COMPONENT: Scheduling
+TITLE: Deterministic Latency
+STATEMENT: >>>
+Worst-case context switch latency shall be ≤X μs (platform-specific).
+<<<
+
+[/SECTION]
+

docs/software_requirements/symmetric_multiprocessing.sdoc

@@ -0,0 +1,80 @@
+[DOCUMENT]
+TITLE: Symmetric Multiprocessing
+REQ_PREFIX: ZEP-SRS-24-
+
+[GRAMMAR]
+IMPORT_FROM_FILE: software_requirements.sgra
+
+[TEXT]
+STATEMENT: >>>
+SPDX-License-Identifier: Apache-2.0
+<<<
+
+[REQUIREMENT]
+UID: ZEP-SRS-24-
+STATUS: Draft
+TYPE: Functional
+COMPONENT: Multi Core
+TITLE: Support operation on more than one CPU
+STATEMENT: >>>
+The Zephyr RTOS shall support operation on more than one physical CPU sharing the same kernel state.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-SRS-2-2
+STATUS: Draft
+TYPE: Functional
+COMPONENT: Multi Core
+TITLE: Running threads on specific CPUs
+STATEMENT: >>>
+The Zephyr RTOS shall provide an interface for running threads on specific sets of CPUs ( default is 1 CPU).
+<<<
+USER_STORY: >>>
+As a Zephyr RTOS user I want Zephyr OS to be able to specify the CPU core or the set of CPU cores on which a thread shall be executed.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-SRS-2-3
+STATUS: Draft
+TYPE: Functional
+COMPONENT: Multi Core
+TITLE: Exclusion between physical CPUs
+STATEMENT: >>>
+The Zephyr RTOS shall provide an interface for mutual exclusion between multiple physical CPUs.
+<<<
+USER_STORY: >>>
+As a Zephyr RTOS user I want Zephyr OS to provide synchronization mechanisms between the CPU cores and the access to common resources.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-SRS-24-
+STATUS: Draft
+TYPE: Functional
+COMPONENT: Scheduling
+TITLE: Affinity Awareness
+STATEMENT: >>>
+The Zephyr RTOS shall honor thread-CPU affinity masks in SMP configurations.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-SRS-24-
+STATUS: Draft
+TYPE: Functional
+COMPONENT: Symmetric Multiprocessing
+TITLE: Cross-CPU Atomicity
+STATEMENT: >>>
+The Zephyr RTOS shall ensure that Spinlocks enforce cross-CPU mutual exclusion for Zephyr RTOS data structures.
+<<<
+
+[REQUIREMENT]
+UID: ZEP-SRS-24-
+STATUS: Draft
+TYPE: Functional
+COMPONENT: Symmetric Multiprocessing
+TITLE: Time sharing of CPU resources
+STATEMENT: >>>
+The Zephyr RTOS shall support time sharing of CPU resources among threads of the same priority.
+<<<
+USER_STORY: >>>
+As a Zephyr RTOS user, I want to be able to configure my RTOS in the way, that the CPU resources are shared evenly among executed threads of the same priority.
+<<<

docs/software_requirements/thread_events.sdoc

@@ -0,0 +1,28 @@
+[DOCUMENT]
+TITLE: Thread Events
+REQ_PREFIX: ZEP-SRS-25-
+
+[GRAMMAR]
+IMPORT_FROM_FILE: software_requirements.sgra
+
+[TEXT]
+STATEMENT: >>>
+SPDX-License-Identifier: Apache-2.0
+<<<
+
+[REQUIREMENT]
+UID: ZEP-SRS-25-
+STATUS: Draft
+TYPE: Functional
+COMPONENT: Thread Events
+TITLE: Scheduling a thread based on an event
+STATEMENT: >>>
+The Zephyr RTOS shall provide an interface to schedule a thread based on an event.
+<<<
+USER_STORY: >>>
+As a Zephyr RTOS user, I want to be able to execute work which reacts on events and interrupts the current executed work.
+<<<
+RELATIONS:
+- TYPE: Parent
+  VALUE: ZEP-SYRS-15
+