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Add TASK_AGE_EXPEDITE_RX to ensure RX task is never starved of time

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Steve Evans 2022-01-12 21:51:58 +00:00
parent c05ad2ec9b
commit 4e47a792d8
3 changed files with 18 additions and 10 deletions
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23
src/main/scheduler/scheduler.c
View file

@ -92,6 +92,8 @@ static FAST_DATA_ZERO_INIT bool gyroEnabled;
static int32_t desiredPeriodCycles; static int32_t desiredPeriodCycles;
static uint32_t lastTargetCycles; static uint32_t lastTargetCycles;
static uint8_t skippedRxAttempts = 0;
#if defined(USE_LATE_TASK_STATISTICS) #if defined(USE_LATE_TASK_STATISTICS)
static int16_t lateTaskCount = 0; static int16_t lateTaskCount = 0;
static uint32_t lateTaskTotal = 0; static uint32_t lateTaskTotal = 0;
@ -569,8 +571,8 @@ FAST_CODE void scheduler(void)
if (task->attr->checkFunc) { if (task->attr->checkFunc) {
// Increase priority for event driven tasks // Increase priority for event driven tasks
if (task->dynamicPriority > 0) { if (task->dynamicPriority > 0) {
task->taskAgeCycles = 1 + (cmpTimeUs(currentTimeUs, task->lastSignaledAtUs) / task->attr->desiredPeriodUs); task->taskAgePeriods = 1 + (cmpTimeUs(currentTimeUs, task->lastSignaledAtUs) / task->attr->desiredPeriodUs);
task->dynamicPriority = 1 + task->attr->staticPriority * task->taskAgeCycles; task->dynamicPriority = 1 + task->attr->staticPriority * task->taskAgePeriods;
} else if (task->attr->checkFunc(currentTimeUs, cmpTimeUs(currentTimeUs, task->lastExecutedAtUs))) { } else if (task->attr->checkFunc(currentTimeUs, cmpTimeUs(currentTimeUs, task->lastExecutedAtUs))) {
const uint32_t checkFuncExecutionTimeUs = cmpTimeUs(micros(), currentTimeUs); const uint32_t checkFuncExecutionTimeUs = cmpTimeUs(micros(), currentTimeUs);
#if !defined(UNIT_TEST) #if !defined(UNIT_TEST)
@ -581,17 +583,17 @@ FAST_CODE void scheduler(void)
checkFuncTotalExecutionTimeUs += checkFuncExecutionTimeUs; // time consumed by scheduler + task checkFuncTotalExecutionTimeUs += checkFuncExecutionTimeUs; // time consumed by scheduler + task
checkFuncMaxExecutionTimeUs = MAX(checkFuncMaxExecutionTimeUs, checkFuncExecutionTimeUs); checkFuncMaxExecutionTimeUs = MAX(checkFuncMaxExecutionTimeUs, checkFuncExecutionTimeUs);
task->lastSignaledAtUs = currentTimeUs; task->lastSignaledAtUs = currentTimeUs;
task->taskAgeCycles = 1; task->taskAgePeriods = 1;
task->dynamicPriority = 1 + task->attr->staticPriority; task->dynamicPriority = 1 + task->attr->staticPriority;
} else { } else {
task->taskAgeCycles = 0; task->taskAgePeriods = 0;
} }
} else { } else {
// Task is time-driven, dynamicPriority is last execution age (measured in desiredPeriods) // Task is time-driven, dynamicPriority is last execution age (measured in desiredPeriods)
// Task age is calculated from last execution // Task age is calculated from last execution
task->taskAgeCycles = (cmpTimeUs(currentTimeUs, task->lastExecutedAtUs) / task->attr->desiredPeriodUs); task->taskAgePeriods = (cmpTimeUs(currentTimeUs, task->lastExecutedAtUs) / task->attr->desiredPeriodUs);
if (task->taskAgeCycles > 0) { if (task->taskAgePeriods > 0) {
task->dynamicPriority = 1 + task->attr->staticPriority * task->taskAgeCycles; task->dynamicPriority = 1 + task->attr->staticPriority * task->taskAgePeriods;
} }
} }
@ -633,6 +635,10 @@ FAST_CODE void scheduler(void)
} }
#endif // USE_LATE_TASK_STATISTICS #endif // USE_LATE_TASK_STATISTICS
if ((currentTask - tasks) == TASK_RX) {
skippedRxAttempts = 0;
}
if ((cyclesOverdue > 0) || (-cyclesOverdue < taskGuardMinCycles)) { if ((cyclesOverdue > 0) || (-cyclesOverdue < taskGuardMinCycles)) {
if (taskGuardCycles < taskGuardMaxCycles) { if (taskGuardCycles < taskGuardMaxCycles) {
taskGuardCycles += taskGuardDeltaUpCycles; taskGuardCycles += taskGuardDeltaUpCycles;
@ -643,7 +649,8 @@ FAST_CODE void scheduler(void)
#if defined(USE_LATE_TASK_STATISTICS) #if defined(USE_LATE_TASK_STATISTICS)
taskCount++; taskCount++;
#endif // USE_LATE_TASK_STATISTICS #endif // USE_LATE_TASK_STATISTICS
} else if (selectedTask->taskAgeCycles > TASK_AGE_EXPEDITE_COUNT) { } else if ((selectedTask->taskAgePeriods > TASK_AGE_EXPEDITE_COUNT) ||
(((selectedTask - tasks) == TASK_RX) && (++skippedRxAttempts > TASK_AGE_EXPEDITE_RX))) {
// If a task has been unable to run, then reduce it's recorded estimated run time to ensure // If a task has been unable to run, then reduce it's recorded estimated run time to ensure
// it's ultimate scheduling // it's ultimate scheduling
selectedTask->anticipatedExecutionTime *= TASK_AGE_EXPEDITE_SCALE; selectedTask->anticipatedExecutionTime *= TASK_AGE_EXPEDITE_SCALE;

3
src/main/scheduler/scheduler.h
View file

@ -47,6 +47,7 @@
// Decay the estimated max task duration by 1/(1 << TASK_EXEC_TIME_SHIFT) on every invocation // Decay the estimated max task duration by 1/(1 << TASK_EXEC_TIME_SHIFT) on every invocation
#define TASK_EXEC_TIME_SHIFT 7 #define TASK_EXEC_TIME_SHIFT 7
#define TASK_AGE_EXPEDITE_RX 25 // Make RX tasks more schedulable if it's failed to be scheduled this many times
#define TASK_AGE_EXPEDITE_COUNT 1 // Make aged tasks more schedulable #define TASK_AGE_EXPEDITE_COUNT 1 // Make aged tasks more schedulable
#define TASK_AGE_EXPEDITE_SCALE 0.9 // By scaling their expected execution time #define TASK_AGE_EXPEDITE_SCALE 0.9 // By scaling their expected execution time
@ -197,7 +198,7 @@ typedef struct {
// Scheduling // Scheduling
uint16_t dynamicPriority; // measurement of how old task was last executed, used to avoid task starvation uint16_t dynamicPriority; // measurement of how old task was last executed, used to avoid task starvation
uint16_t taskAgeCycles; uint16_t taskAgePeriods;
timeDelta_t taskLatestDeltaTimeUs; timeDelta_t taskLatestDeltaTimeUs;
timeUs_t lastExecutedAtUs; // last time of invocation timeUs_t lastExecutedAtUs; // last time of invocation
timeUs_t lastSignaledAtUs; // time of invocation event for event-driven tasks timeUs_t lastSignaledAtUs; // time of invocation event for event-driven tasks

2
src/test/unit/scheduler_unittest.cc
View file

@ -396,7 +396,7 @@ TEST(SchedulerUnittest, TestTwoTasks)
simulatedTime = startTime; simulatedTime = startTime;
tasks[TASK_ACCEL].lastExecutedAtUs = simulatedTime; tasks[TASK_ACCEL].lastExecutedAtUs = simulatedTime;
tasks[TASK_ATTITUDE].lastExecutedAtUs = tasks[TASK_ACCEL].lastExecutedAtUs - TEST_UPDATE_ATTITUDE_TIME; tasks[TASK_ATTITUDE].lastExecutedAtUs = tasks[TASK_ACCEL].lastExecutedAtUs - TEST_UPDATE_ATTITUDE_TIME;
EXPECT_EQ(0, tasks[TASK_ATTITUDE].taskAgeCycles); EXPECT_EQ(0, tasks[TASK_ATTITUDE].taskAgePeriods);
// run the scheduler // run the scheduler
scheduler(); scheduler();
// no tasks should have run, since neither task's desired time has elapsed // no tasks should have run, since neither task's desired time has elapsed