[rtems-central commit] spec: Improve scheduler yield specification
Sebastian Huber
sebh at rtems.org
Wed Dec 8 16:26:45 UTC 2021
Module: rtems-central
Branch: master
Commit: 8881feb20fd0ec1596938b473183aa287ad61c49
Changeset: http://git.rtems.org/rtems-central/commit/?id=8881feb20fd0ec1596938b473183aa287ad61c49
Author: Sebastian Huber <sebastian.huber at embedded-brains.de>
Date: Mon Dec 6 15:38:21 2021 +0100
spec: Improve scheduler yield specification
---
spec/score/sched/req/yield.yml | 131 +++++++++++++++++++++++++++++++++++------
1 file changed, 113 insertions(+), 18 deletions(-)
diff --git a/spec/score/sched/req/yield.yml b/spec/score/sched/req/yield.yml
index eb1dade..49b86f0 100644
--- a/spec/score/sched/req/yield.yml
+++ b/spec/score/sched/req/yield.yml
@@ -96,6 +96,25 @@ pre-conditions:
While the thread is scheduled on a ${/glossary/scheduler-helping:/term}.
test-epilogue: null
test-prologue: null
+- name: HomeSchedulerState
+ states:
+ - name: Blocked
+ test-code: |
+ ctx->ready = false;
+ text: |
+ The thread shall be blocked in its ${/glossary/scheduler-home:/term}.
+ - name: Scheduled
+ test-code: |
+ ctx->ready = false;
+ text: |
+ The thread shall be scheduled in its ${/glossary/scheduler-home:/term}.
+ - name: Ready
+ test-code: |
+ ctx->ready = true;
+ text: |
+ The thread shall be ready in its ${/glossary/scheduler-home:/term}.
+ test-epilogue: null
+ test-prologue: null
- name: Sticky
states:
- name: 'Yes'
@@ -110,22 +129,20 @@ pre-conditions:
While the thread not sticky.
test-epilogue: null
test-prologue: null
-- name: OtherReady
+- name: Other
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.
+ While at least one ready thread with a priority equal to the priority of
+ the thread exists in the ${/glossary/scheduler-home:/term} 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.
+ While no ready thread with a priority equal to the priority of the thread
+ exists in the ${/glossary/scheduler-home:/term} of the thread.
test-epilogue: null
test-prologue: null
rationale: null
@@ -140,8 +157,14 @@ skip-reasons:
StickyNeedsSMP: |
A thread may be sticky only where the system was built with SMP support
enabled.
+ Sticky: |
+ Sticky threads are never blocked in their home scheduler. Only sticky
+ threads may be scheduled on two schedulers at the same time.
+ HomeNeedsScheduled: |
+ While a thread uses its home scheduler, it is scheduled in the home scheduler.
test-action: |
const Per_CPU_Control *cpu;
+ bool other_busy;
if ( ctx->has_helping ) {
TQMutexObtain( &ctx->tq_ctx, TQ_MUTEX_A );
@@ -156,13 +179,21 @@ test-action: |
MoveToHelping( ctx );
}
+ TQResetCounter( &ctx->tq_ctx );
+
+ if ( ctx->use_helping && ctx->ready ) {
+ ctx->tq_ctx.busy_wait[ COUNTER ] = true;
+ TQSend( &ctx->tq_ctx, COUNTER, TQ_EVENT_COUNT | TQ_EVENT_BUSY_WAIT );
+ other_busy = true;
+ } else {
+ other_busy = false;
+ }
+
if ( ctx->sticky ) {
ObtainMutex( ctx->sticky_mutex );
}
- TQResetCounter( &ctx->tq_ctx );
-
- if ( ctx->other_ready ) {
+ if ( ctx->other_ready && !other_busy ) {
TQSend( &ctx->tq_ctx, COUNTER, TQ_EVENT_COUNT );
}
@@ -174,6 +205,8 @@ test-action: |
TQSchedulerRecordStop( &ctx->tq_ctx );
#if defined(RTEMS_SMP)
+ ctx->tq_ctx.busy_wait[ COUNTER ] = false;
+
while ( cpu->heir == ctx->tq_ctx.worker_tcb[ COUNTER ] ) {
RTEMS_COMPILER_MEMORY_BARRIER();
}
@@ -223,13 +256,19 @@ test-context:
member: |
bool use_helping
- brief: |
+ If this member is true, then the runner shall be ready in its home
+ scheduler.
+ description: null
+ member: |
+ bool ready
+- 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.
+ the runner shall be ready with an equal priority.
description: null
member: |
bool other_ready
@@ -324,19 +363,36 @@ transition-map:
- if:
pre-conditions:
UsedScheduler: Home
- OtherReady: 'No'
+ HomeSchedulerState: Scheduled
+ Other: 'No'
then: Scheduled
- if:
pre-conditions:
+ UsedScheduler: Home
+ HomeSchedulerState: Scheduled
+ Other: 'Yes'
+ then: Ready
+ - if:
+ pre-conditions:
EligibleScheduler: Helping
UsedScheduler: Helping
+ HomeSchedulerState: Scheduled
Sticky: 'Yes'
- OtherReady: 'No'
+ Other: 'No'
then: Idle
- if:
pre-conditions:
EligibleScheduler: Helping
UsedScheduler: Helping
+ HomeSchedulerState: Scheduled
+ Sticky: 'Yes'
+ Other: 'Yes'
+ then: Ready
+ - if:
+ pre-conditions:
+ EligibleScheduler: Helping
+ UsedScheduler: Helping
+ HomeSchedulerState: Blocked
Sticky: 'No'
then: Blocked
- else: Ready
@@ -345,14 +401,16 @@ transition-map:
pre-conditions:
EligibleScheduler: Helping
UsedScheduler: Home
- OtherReady: 'Yes'
+ HomeSchedulerState: Scheduled
+ Other: 'Yes'
then: 'Yes'
- else: 'No'
pre-conditions:
EligibleScheduler: all
UsedScheduler: all
+ HomeSchedulerState: all
Sticky: all
- OtherReady: all
+ Other: all
- enabled-by: true
post-conditions: HelpingNeedsHelping
pre-conditions:
@@ -360,8 +418,9 @@ transition-map:
- Home
UsedScheduler:
- Helping
+ HomeSchedulerState: all
Sticky: all
- OtherReady: all
+ Other: all
- enabled-by:
not: RTEMS_SMP
post-conditions: HelpingNeedsSMP
@@ -369,15 +428,51 @@ transition-map:
EligibleScheduler:
- Helping
UsedScheduler: all
+ HomeSchedulerState: all
Sticky: all
- OtherReady: all
+ Other: all
- enabled-by:
not: RTEMS_SMP
post-conditions: StickyNeedsSMP
pre-conditions:
EligibleScheduler: all
UsedScheduler: all
+ HomeSchedulerState: all
+ Sticky:
+ - 'Yes'
+ Other: all
+- enabled-by: true
+ post-conditions: Sticky
+ pre-conditions:
+ EligibleScheduler:
+ - Helping
+ UsedScheduler:
+ - Helping
+ HomeSchedulerState:
+ - Scheduled
+ - Ready
+ Sticky:
+ - 'No'
+ Other: all
+- enabled-by: true
+ post-conditions: Sticky
+ pre-conditions:
+ EligibleScheduler: all
+ UsedScheduler: all
+ HomeSchedulerState:
+ - Blocked
Sticky:
- 'Yes'
- OtherReady: all
+ Other: all
+- enabled-by: true
+ post-conditions: HomeNeedsScheduled
+ pre-conditions:
+ EligibleScheduler: all
+ UsedScheduler:
+ - Home
+ HomeSchedulerState:
+ - Blocked
+ - Ready
+ Sticky: all
+ Other: all
type: requirement
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