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scheduler: test round robin threads
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Add test SCHED0023 to check that round robin threads are indeed
scheduled round robin.

Signed-off-by: Gerwin Klein <[email protected]>
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lsf37 committed Jul 25, 2024
1 parent 6830a7f commit 0f18a9e
Showing 1 changed file with 63 additions and 0 deletions.
63 changes: 63 additions & 0 deletions apps/sel4test-tests/src/tests/scheduler.c
Original file line number Diff line number Diff line change
Expand Up @@ -1695,3 +1695,66 @@ static int test_changing_affinity(struct env *env)
}
DEFINE_TEST(SCHED0022, "test changing a helper threads core", test_changing_affinity,
(config_set(CONFIG_KERNEL_MCS) &&(CONFIG_MAX_NUM_NODES > 1)));


#define SCHED0023_NUM_ROUNDS 5
static volatile unsigned sched_0023_dummy = 0;

/* used in test_round_robin below */
static void round_robin_thread(int id, volatile unsigned long *counters)
{
/* assumes counters are initialised already */
while (counters[id] < SCHED0023_NUM_ROUNDS) {
counters[id]++;
/* thread "id" should run after thread "id-1", so we should be at the same
count after incrementing if we are scheduled round robin. */
if (0 < id) {
test_eq(counters[id], counters[id - 1]);
}
printf("Tick (%d)\n", id);
/* busy wait so we can be preempted at least once before we increment
the counter again */
for (int i = 0; i < 1000000; i++) {
sched_0023_dummy++;
}
}

test_eq(counters[id], (unsigned long) SCHED0023_NUM_ROUNDS);
}

/* Test that round robin threads are indeed round robin. */
static int test_round_robin(struct env *env)
{
const int num_threads = 5;
helper_thread_t helpers[num_threads];
volatile unsigned long counters[num_threads];

for (int i = 0; i < num_threads; i++) {
counters[i] = 0;
create_helper_thread(env, &helpers[i]);
/* keep at lower priority first, we will drop our own priority when they are all started */
set_helper_priority(env, &helpers[i], env->priority - 1);
/* budget == priority makes them round robin */
set_helper_sched_params(env, &helpers[i], 1 * US_IN_MS, 1 * US_IN_MS, 0);
}

/* start in reverse order, because most recently started is first in scheduling
queue and we want id 0 to run first */
for (int i = num_threads - 1; i >= 0; i--) {
start_helper(env, &helpers[i],
(helper_fn_t) round_robin_thread, i, (seL4_Word) counters, 0, 0);
}

int error = seL4_TCB_SetPriority(env->tcb, env->tcb, env->priority - 2);
test_error_eq(error, seL4_NoError);

/* We will only get to run again when the round robin threads have all finished,
because they are higher priority */
for (int i = 0; i < num_threads; i++) {
test_eq(counters[i], (unsigned long) SCHED0023_NUM_ROUNDS);
}

return sel4test_get_result();
}
DEFINE_TEST(SCHED0023, "test round robin threads", test_round_robin,
(config_set(CONFIG_KERNEL_MCS)));

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