On 24/03/2025 09:44, Philipp Stanner wrote:
On Mon, 2025-03-24 at 09:26 +0000, Tvrtko Ursulin wrote:
There has repeatedly been quite a bit of apprehension when any change
to the DRM
scheduler is proposed, with two main reasons being code base is
considered
fragile, not well understood and not very well documented, and
secondly the lack
of systematic testing outside the vendor specific tests suites and/or
test
farms.
This series is an attempt to dislodge this status quo by adding some
unit tests
using the kunit framework.
General approach is that there is a mock "hardware" backend which can
be
controlled from tests, which in turn allows exercising various
scheduler code
paths.
Only some simple basic tests get added in the series and hopefully it
is easy to
understand what tests are doing.
An obligatory "screenshot" for reference:
[14:09:05] ============ drm_sched_basic_tests (3 subtests)
============
[14:09:06] [PASSED] drm_sched_basic_submit
[14:09:06] ================== drm_sched_basic_test
===================
[14:09:06] [PASSED] A queue of jobs in a single entity
[14:09:06] [PASSED] A chain of dependent jobs across multiple
entities
[14:09:06] [PASSED] Multiple independent job queues
[14:09:06] [PASSED] Multiple inter-dependent job queues
[14:09:07] ============== [PASSED] drm_sched_basic_test
===============
[14:09:07] [PASSED] drm_sched_basic_entity_cleanup
[14:09:07] ============== [PASSED] drm_sched_basic_tests
==============
[14:09:07] ======== drm_sched_basic_timeout_tests (1 subtest)
=========
[14:09:08] [PASSED] drm_sched_basic_timeout
[14:09:08] ========== [PASSED] drm_sched_basic_timeout_tests
==========
[14:09:08] ======= drm_sched_basic_priority_tests (2 subtests)
========
[14:09:10] [PASSED] drm_sched_priorities
[14:09:10] [PASSED] drm_sched_change_priority
[14:09:10] ========= [PASSED] drm_sched_basic_priority_tests
==========
[14:09:10] ====== drm_sched_basic_modify_sched_tests (1 subtest)
======
[14:09:11] [PASSED] drm_sched_test_modify_sched
[14:09:11] ======= [PASSED] drm_sched_basic_modify_sched_tests
========
[14:09:11] ======== drm_sched_basic_credits_tests (1 subtest)
=========
[14:09:12] [PASSED] drm_sched_test_credits
[14:09:12] ========== [PASSED] drm_sched_basic_credits_tests
==========
[14:09:12]
============================================================
[14:09:12] Testing complete. Ran 11 tests: passed: 11
[14:09:13] Elapsed time: 13.539s total, 0.001s configuring, 3.004s
building, 10.462s running
v2:
* Parameterize a bunch of similar tests.
* Improve test commentary.
* Rename TDR test to timeout. (Christian)
* Improve quality and consistency of naming. (Philipp)
RFC v2 -> series v1:
* Rebased for drm_sched_init changes.
* Fixed modular build.
* Added some comments.
* Filename renames. (Philipp)
v2:
* Dealt with a bunch of checkpatch warnings.
v3:
* Some mock API renames, kerneldoc grammar fixes and indentation
fixes.
v4:
* Fix use after free caused by relying on scheduler fence for
querying status.
* Kerneldoc fixes.
v5:
* Cleanup in-flight jobs on scheduler shutdown.
* Change hang_limit to 1.
v6:
* Use KUNIT_ASSERT_TRUE/FALSE.
* Fixed patch titles.
* Added credit_limit test.
* Added CONFIG_DRM_SCHED_KUNIT_TEST_ASPIRATIONAL.
v7:
* v6 omitted to send the first patch by mistake.
v8:
* Removed CONFIG_DRM_SCHED_KUNIT_TEST_ASPIRATIONAL for now.
* Added Christian's acks.
v9:
* Fixed a potential memory leak caused by a race condition on mock
scheduler
shutdown. In order to reliably clean up everything, we have keep
track of
jobs even past the signalling stage, all until either DRM sched
core managed
to run the ->free_job() callback, or until mock scheduler teardown
from the
test.
v10:
* Rebase for a merge conflict in Kconfig.
Cc: Christian König <christian.koe...@amd.com>
Cc: Danilo Krummrich <d...@kernel.org>
Cc: Matthew Brost <matthew.br...@intel.com>
Cc: Philipp Stanner <pha...@kernel.org>
Tvrtko Ursulin (6):
drm: Move some options to separate new Kconfig
drm/sched: Add scheduler unit testing infrastructure and some basic
tests
drm/sched: Add a simple timeout test
drm/sched: Add basic priority tests
drm/sched: Add a basic test for modifying entities scheduler list
drm/sched: Add a basic test for checking credit limit
drivers/gpu/drm/Kconfig | 110 +---
drivers/gpu/drm/Kconfig.debug | 116 +++++
drivers/gpu/drm/scheduler/.kunitconfig | 12 +
drivers/gpu/drm/scheduler/Makefile | 2 +
drivers/gpu/drm/scheduler/tests/Makefile | 7 +
.../gpu/drm/scheduler/tests/mock_scheduler.c | 359 +++++++++++++
drivers/gpu/drm/scheduler/tests/sched_tests.h | 226 +++++++++
drivers/gpu/drm/scheduler/tests/tests_basic.c | 476
++++++++++++++++++
8 files changed, 1203 insertions(+), 105 deletions(-)
create mode 100644 drivers/gpu/drm/Kconfig.debug
create mode 100644 drivers/gpu/drm/scheduler/.kunitconfig
create mode 100644 drivers/gpu/drm/scheduler/tests/Makefile
create mode 100644 drivers/gpu/drm/scheduler/tests/mock_scheduler.c
create mode 100644 drivers/gpu/drm/scheduler/tests/sched_tests.h
create mode 100644 drivers/gpu/drm/scheduler/tests/tests_basic.c
Applied to drm-misc-next
Thanks for your endurance!
Thank you for the much needed scrutiny and testing!
Regards,
Tvrtko
