[rtems-central commit] spec: Specify scheduler yield
Sebastian Huber
sebh at rtems.org
Tue Nov 9 14:47:48 UTC 2021
Module: rtems-central
Branch: master
Commit: 3fcf99485f9b688d3827e8f04782b645f9c4e26c
Changeset: http://git.rtems.org/rtems-central/commit/?id=3fcf99485f9b688d3827e8f04782b645f9c4e26c
Author: Sebastian Huber <sebastian.huber at embedded-brains.de>
Date: Mon Nov 8 15:34:48 2021 +0100
spec: Specify scheduler yield
---
spec/score/sched/req/yield.yml | 386 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 386 insertions(+)
diff --git a/spec/score/sched/req/yield.yml b/spec/score/sched/req/yield.yml
new file mode 100644
index 0000000..c057f33
--- /dev/null
+++ b/spec/score/sched/req/yield.yml
@@ -0,0 +1,386 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 2021 embedded brains GmbH (http://www.embedded-brains.de)
+enabled-by: true
+functional-type: action
+links:
+- role: requirement-refinement
+ uid: group
+post-conditions:
+- name: HomeSchedulerState
+ states:
+ - name: Blocked
+ test-code: |
+ T_true( ctx->is_idle_after_yield );
+ T_eq_u32( ctx->cpu_after_yield, 1 );
+ text: |
+ The thread shall be blocked in its ${/glossary/scheduler-home:/term}.
+ - name: Scheduled
+ test-code: |
+ T_false( ctx->is_idle_before_yield );
+ T_false( ctx->is_idle_after_yield );
+ T_eq_u32( GetCounter( ctx ), 0 );
+ T_eq_u32( ctx->cpu_after_yield, 0 );
+ text: |
+ The thread shall be scheduled in its ${/glossary/scheduler-home:/term}.
+ - name: Ready
+ test-code: |
+ T_eq_u32( GetCounter( ctx ), 1 );
+ text: |
+ The thread shall be ready in its ${/glossary/scheduler-home:/term}.
+ - name: Idle
+ test-code: |
+ T_true( ctx->is_idle_before_yield );
+ T_true( ctx->is_idle_after_yield );
+ T_eq_u32( GetCounter( ctx ), 0 );
+ T_eq_u32( ctx->cpu_after_yield, 1 );
+ text: |
+ An idle thread shall execute on behalf of the thread in its
+ ${/glossary/scheduler-home:/term}.
+ test-epilogue: null
+ test-prologue: null
+- name: AskForHelp
+ states:
+ - name: 'Yes'
+ test-code: |
+ event = TQGetNextAskForHelp( &ctx->tq_ctx, &index );
+ T_eq_ptr( event->thread, ctx->tq_ctx.runner_tcb );
+
+ event = TQGetNextAskForHelp( &ctx->tq_ctx, &index );
+ T_eq_ptr( event->thread, ctx->tq_ctx.runner_tcb );
+
+ event = TQGetNextAskForHelp( &ctx->tq_ctx, &index );
+ T_eq_ptr( event, &T_scheduler_event_null );
+ text: |
+ The thread shall ask all its ${/glossary/scheduler-eligible:/term} for
+ help.
+ - name: 'No'
+ test-code: |
+ event = TQGetNextAskForHelp( &ctx->tq_ctx, &index );
+ T_eq_ptr( event, &T_scheduler_event_null );
+ text: |
+ The thread shall not ask for help.
+ test-epilogue: null
+ test-prologue: |
+ size_t index;
+ const T_scheduler_event *event;
+
+ index = 0;
+pre-conditions:
+- name: EligibleScheduler
+ states:
+ - name: Home
+ test-code: |
+ ctx->has_helping = false;
+ text: |
+ While the only ${/glossary/scheduler-eligible:/term} of the thread is the
+ ${/glossary/scheduler-home:/term}.
+ - name: Helping
+ test-code: |
+ ctx->has_helping = true;
+ text: |
+ While the thread has at least one ${/glossary/scheduler-helping:/term}.
+ test-epilogue: null
+ test-prologue: null
+- name: UsedScheduler
+ states:
+ - name: Home
+ test-code: |
+ ctx->use_helping = false;
+ text: |
+ While the thread is scheduled on the ${/glossary/scheduler-home:/term}.
+ - name: Helping
+ test-code: |
+ ctx->use_helping = true;
+ text: |
+ While the thread is scheduled on a ${/glossary/scheduler-helping:/term}.
+ test-epilogue: null
+ test-prologue: null
+- name: Sticky
+ states:
+ - name: 'Yes'
+ test-code: |
+ ctx->sticky = true;
+ text: |
+ While the thread is sticky.
+ - name: 'No'
+ test-code: |
+ ctx->sticky = false;
+ text: |
+ While the thread not sticky.
+ test-epilogue: null
+ test-prologue: null
+- name: OtherReady
+ states:
+ - name: 'Yes'
+ test-code: |
+ ctx->other_ready = true;
+ text: |
+ While at least one other thread is ready in the
+ ${/glossary/scheduler-home:/term} of the thread,
+ while the priority of the other thread with respect to the scheduler is
+ equal to the priority of the thread.
+ - name: 'No'
+ test-code: |
+ ctx->other_ready = false;
+ text: |
+ While no other non-idle thread is ready in the
+ ${/glossary/scheduler-home:/term} of the thread.
+ test-epilogue: null
+ test-prologue: null
+rationale: null
+references: []
+requirement-type: functional
+skip-reasons:
+ HelpingNeedsHelping: |
+ In order to use a helping scheduler a thread needs a helping scheduler.
+ HelpingNeedsSMP: |
+ A helping scheduler is only available where the system was built with SMP
+ support enabled.
+ StickyNeedsSMP: |
+ A thread may be sticky only where the system was built with SMP support
+ enabled.
+test-action: |
+ const Per_CPU_Control *cpu;
+
+ if ( ctx->has_helping ) {
+ TQMutexObtain( &ctx->tq_ctx, TQ_MUTEX_A );
+ TQSendAndWaitForExecutionStop(
+ &ctx->tq_ctx,
+ HELPER,
+ TQ_EVENT_MUTEX_A_OBTAIN
+ );
+ }
+
+ if ( ctx->use_helping ) {
+ MoveToHelping( ctx );
+ }
+
+ if ( ctx->sticky ) {
+ ObtainMutex( ctx->sticky_mutex );
+ }
+
+ TQResetCounter( &ctx->tq_ctx );
+
+ if ( ctx->other_ready ) {
+ TQSend( &ctx->tq_ctx, COUNTER, TQ_EVENT_COUNT );
+ }
+
+ cpu = _Per_CPU_Get_by_index( 0 );
+ ctx->is_idle_before_yield = cpu->heir->is_idle;
+
+ TQSchedulerRecordStart( &ctx->tq_ctx );
+ Yield();
+ TQSchedulerRecordStop( &ctx->tq_ctx );
+
+ #if defined(RTEMS_SMP)
+ while ( cpu->heir == ctx->tq_ctx.worker_tcb[ COUNTER ] ) {
+ RTEMS_COMPILER_MEMORY_BARRIER();
+ }
+ #endif
+
+ ctx->is_idle_after_yield = cpu->heir->is_idle;
+ ctx->cpu_after_yield = rtems_scheduler_get_processor();
+
+ if ( ctx->sticky ) {
+ ReleaseMutex( ctx->sticky_mutex );
+ }
+
+ if ( ctx->has_helping ) {
+ TQMutexRelease( &ctx->tq_ctx, TQ_MUTEX_A );
+ TQSendAndWaitForExecutionStop(
+ &ctx->tq_ctx,
+ HELPER,
+ TQ_EVENT_MUTEX_A_RELEASE
+ );
+ }
+test-brief: null
+test-cleanup: null
+test-context:
+- brief: |
+ This member contains the thread queue test context.
+ description: null
+ member: |
+ TQContext tq_ctx
+- brief: |
+ This member contains the identifier of a sticky mutex.
+ description: null
+ member: |
+ rtems_id sticky_mutex
+- brief: |
+ This member contains the processor index after yielding.
+ description: null
+ member: |
+ uint32_t cpu_after_yield
+- brief: |
+ If this member is true, then the runner shall have a helping scheduler.
+ description: null
+ member: |
+ bool has_helping
+- brief: |
+ If this member is true, then the runner shall use a helping scheduler.
+ description: null
+ member: |
+ bool use_helping
+- brief: |
+ If this member is true, then the runner shall be sticky.
+ description: null
+ member: |
+ bool sticky
+- brief: |
+ If this member is true, then another ready task in the home scheduler of
+ the runner shall exist.
+ description: null
+ member: |
+ bool other_ready
+- brief: |
+ If this member is true, then the processor zero was idle before yielding.
+ description: null
+ member: |
+ bool is_idle_before_yield
+- brief: |
+ If this member is true, then the processor zero was idle after yielding.
+ description: null
+ member: |
+ bool is_idle_after_yield
+test-context-support: null
+test-description: null
+test-header: null
+test-includes:
+- rtems.h
+- rtems/test-scheduler.h
+- rtems/score/percpu.h
+test-local-includes:
+- tx-support.h
+- tx-thread-queue.h
+test-prepare: null
+test-setup:
+ brief: null
+ code: |
+ rtems_status_code sc;
+
+ memset( ctx, 0, sizeof( *ctx ) );
+ ctx->tq_ctx.enqueue_prepare = TQEnqueuePrepareDefault;
+ ctx->tq_ctx.enqueue_done = TQEnqueueDoneDefault;
+ ctx->tq_ctx.enqueue = TQEnqueueClassicSem;
+ ctx->tq_ctx.surrender = TQSurrenderClassicSem;
+ ctx->tq_ctx.convert_status = TQConvertStatusClassic;
+ TQInitialize( &ctx->tq_ctx );
+
+ sc = rtems_semaphore_create(
+ rtems_build_name( 'M', 'U', 'T', 'X' ),
+ 1,
+ RTEMS_BINARY_SEMAPHORE | RTEMS_PRIORITY |
+ RTEMS_MULTIPROCESSOR_RESOURCE_SHARING,
+ PRIO_NORMAL,
+ &ctx->sticky_mutex
+ );
+ T_rsc_success( sc );
+
+ TQSetPriority( &ctx->tq_ctx, COUNTER, PRIO_NORMAL );
+
+ #if defined(RTEMS_SMP)
+ TQSetScheduler( &ctx->tq_ctx, HELPER, SCHEDULER_B_ID, PRIO_NORMAL );
+ TQSetPriority( &ctx->tq_ctx, MOVER, PRIO_HIGH );
+ #endif
+ description: null
+test-stop: null
+test-support: |
+ #define COUNTER TQ_BLOCKER_A
+
+ #define HELPER TQ_BLOCKER_B
+
+ #define MOVER TQ_BLOCKER_C
+
+ typedef ${.:/test-context-type} Context;
+
+ static void MoveToHelping( Context *ctx )
+ {
+ ctx->tq_ctx.busy_wait[ MOVER ] = true;
+ TQSend( &ctx->tq_ctx, MOVER, TQ_EVENT_BUSY_WAIT );
+
+ while ( rtems_scheduler_get_processor() != 1 ) {
+ /* Wait */
+ }
+
+ ctx->tq_ctx.busy_wait[ MOVER ] = false;
+ TQWaitForExecutionStop( &ctx->tq_ctx, MOVER );
+ }
+
+ static uint32_t GetCounter( const Context *ctx )
+ {
+ return TQGetWorkerCounter( &ctx->tq_ctx, COUNTER );
+ }
+test-target: testsuites/validation/tc-sched-yield.c
+test-teardown:
+ brief: null
+ code: |
+ TQDestroy( &ctx->tq_ctx );
+ DeleteMutex( ctx->sticky_mutex );
+ description: null
+text: |
+ When the thread yields.
+transition-map:
+- enabled-by: true
+ post-conditions:
+ HomeSchedulerState:
+ - if:
+ pre-conditions:
+ UsedScheduler: Home
+ OtherReady: 'No'
+ then: Scheduled
+ - if:
+ pre-conditions:
+ EligibleScheduler: Helping
+ UsedScheduler: Helping
+ Sticky: 'Yes'
+ OtherReady: 'No'
+ then: Idle
+ - if:
+ pre-conditions:
+ EligibleScheduler: Helping
+ UsedScheduler: Helping
+ Sticky: 'No'
+ then: Blocked
+ - else: Ready
+ AskForHelp:
+ - if:
+ pre-conditions:
+ EligibleScheduler: Helping
+ UsedScheduler: Home
+ OtherReady: 'Yes'
+ then: 'Yes'
+ - else: 'No'
+ pre-conditions:
+ EligibleScheduler: all
+ UsedScheduler: all
+ Sticky: all
+ OtherReady: all
+- enabled-by: true
+ post-conditions: HelpingNeedsHelping
+ pre-conditions:
+ EligibleScheduler:
+ - Home
+ UsedScheduler:
+ - Helping
+ Sticky: all
+ OtherReady: all
+- enabled-by:
+ not: RTEMS_SMP
+ post-conditions: HelpingNeedsSMP
+ pre-conditions:
+ EligibleScheduler:
+ - Helping
+ UsedScheduler: all
+ Sticky: all
+ OtherReady: all
+- enabled-by:
+ not: RTEMS_SMP
+ post-conditions: StickyNeedsSMP
+ pre-conditions:
+ EligibleScheduler: all
+ UsedScheduler: all
+ Sticky:
+ - 'Yes'
+ OtherReady: all
+type: requirement
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