reel_board: tests/kernel/sched/schedule_api/ fails on multiple boards

[s-kelvin]

EDIT: Affects multiple Nordic boards and mec15xxevb_assy6853

Describe the bug
Running tests/kernel/sched/schedule_api/ on reel board. Assertion in test_slice_reset failed in both kernel.scheduler and kernel.scheduler.multiq testcases.

To Reproduce
Steps to reproduce the behavior:

1. west build -p auto -b reel_board tests/kernel/sched/schedule_api/
2. west flash

Expected behavior
Test should pass.

Impact
Test suite fails.

Logs and console output

*** Booting Zephyr OS build zephyr-v2.4.0-1133-ge4e3ab3cc315  ***
Running test suite threads_scheduling
===================================================================
START - test_bad_priorities
PASS - test_bad_priorities
===================================================================
START - test_priority_cooperative
PASS - test_priority_cooperative
===================================================================
START - test_priority_preemptible
PASS - test_priority_preemptible
===================================================================
START - test_priority_preemptible_wait_prio
PASS - test_priority_preemptible_wait_prio
===================================================================
START - test_yield_cooperative
PASS - test_yield_cooperative
===================================================================
START - test_sleep_cooperative
PASS - test_sleep_cooperative
===================================================================
START - test_sleep_wakeup_preemptible
PASS - test_sleep_wakeup_preemptible
===================================================================
START - test_pending_thread_wakeup
PASS - test_pending_thread_wakeup
===================================================================
START - test_time_slicing_preemptible
PASS - test_time_slicing_preemptible
===================================================================
START - test_time_slicing_disable_preemptible
PASS - test_time_slicing_disable_preemptible
===================================================================
START - test_lock_preemptible
PASS - test_lock_preemptible
===================================================================
START - test_unlock_preemptible
PASS - test_unlock_preemptible
===================================================================
START - test_unlock_nested_sched_lock
PASS - test_unlock_nested_sched_lock
===================================================================
START - test_sched_is_preempt_thread
PASS - test_sched_is_preempt_thread
===================================================================
START - test_slice_reset
Assertion failed at WEST_TOPDIR/zephyr/tests/kernel/sched/schedule_api/src/test_sched_timeslice_reset.c:91: thread_time_slice: (t <= expected_slice_max is false)
timeslice too big, expected 6555 got 7208
Assertion failed at WEST_TOPDIR/zephyr/tests/kernel/sched/schedule_api/src/test_sched_timeslice_reset.c:88: thread_time_slice: (t >= expected_slice_min is false)
timeslice too small, expected 6553 got 617
FAIL - test_slice_reset
===================================================================
START - test_slice_scheduling
ABCDEFGHI
ABCDEFGHI
ABCDEFGHI
ABCDEFGHI
ABCDEFGHI
ABCDEFGHI
PASS - test_slice_scheduling
===================================================================
START - test_priority_scheduling
ABCDEFGHI
ABCDEFGHI
ABCDEFGHI
ABCDEFGHI
ABCDEFGHI
PASS - test_priority_scheduling
===================================================================
START - test_wakeup_expired_timer_thread
PASS - test_wakeup_expired_timer_thread
===================================================================
START - test_user_k_wakeup
PASS - test_user_k_wakeup
===================================================================
START - test_user_k_is_preempt
PASS - test_user_k_is_preempt
===================================================================
Test suite threads_scheduling failed.
===================================================================
PROJECT EXECUTION FAILED

Environment (please complete the following information):

• OS: Linux Ubuntu 18.04.4 LTS
• Toolchain Zephyr SDK 0.11.2
• Zephyr version zephyr-v2.4.0-1133-ge4e3ab3cc315

[maksimmasalski]

Fails on the mec15xxevb_assy6853 too. In multiq configuration and in standard without it.
kernel.scheduler.kernel.scheduler.slice_reset Fails
kernel.scheduler.kernel.scheduler.multiq.slice_reset Fails

[pabigot]

This is specific to CONFIG_TIMESLICING=y, was introduced at 0875740, and is reproducible on multiple Nordic boards.

Given that the previous sync waited for a "millisecond" boundary I'm wondering if the test has an implicit assumption that milliseconds can be precisely represented, which is not true on Nordic hardware.

[andyross]

Was just pointed to this. Indeed, this test looks to me like it's doing ms math on its timeouts.

[maksimmasalski]

Was just pointed to this. Indeed, this test looks to me like it's doing ms math on its timeouts.

What time you can expect to submit a PR? Do you need any help?

[ABOSTM]

On STM32 boards, I found that this test fails depending on clock frequency,
and I propose a fix by increasing SLICE_SIZE:
#30791