[PATCH v2 2/5] drm/scheduler: Add scheduler unit testing infrastructure and some basic tests

Tvrtko Ursulin tvrtko.ursulin at igalia.com
Mon Mar 3 15:53:33 UTC 2025


On 03/03/2025 11:38, Philipp Stanner wrote:
> Sry for being late to the party, am a bit busy with defusing my own
> dynamite <.<
> 
> On Fri, 2025-02-21 at 12:09 +0000, Tvrtko Ursulin wrote:
>> Implement a mock scheduler backend and add some basic test to
>> exercise the
>> core scheduler code paths.
>>
>> Mock backend (kind of like a very simple mock GPU) can either process
>> jobs
>> by tests manually advancing the "timeline" job at a time, or
>> alternatively
>> jobs can be configured with a time duration in which case they get
>> completed asynchronously from the unit test code.
>>
>> Core scheduler classes are subclassed to support this mock
>> implementation.
>>
>> The tests added are just a few simple submission patterns.
>>
>> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>
>> Suggested-by: Philipp Stanner <phasta at kernel.org>
>> Cc: Christian König <christian.koenig at amd.com>
>> Cc: Danilo Krummrich <dakr at kernel.org>
>> Cc: Matthew Brost <matthew.brost at intel.com>
>> Cc: Philipp Stanner <phasta at kernel.org>
>> ---
>>   drivers/gpu/drm/Kconfig.debug                 |  12 +
>>   drivers/gpu/drm/scheduler/.kunitconfig        |  12 +
>>   drivers/gpu/drm/scheduler/Makefile            |   2 +
>>   drivers/gpu/drm/scheduler/tests/Makefile      |   6 +
>>   .../gpu/drm/scheduler/tests/mock_scheduler.c  | 317
>> ++++++++++++++++++
>>   drivers/gpu/drm/scheduler/tests/sched_tests.h | 218 ++++++++++++
>>   drivers/gpu/drm/scheduler/tests/tests_basic.c | 197 +++++++++++
>>   7 files changed, 764 insertions(+)
>>   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
>>
>> diff --git a/drivers/gpu/drm/Kconfig.debug
>> b/drivers/gpu/drm/Kconfig.debug
>> index 601d7e07d421..6fd4c5669400 100644
>> --- a/drivers/gpu/drm/Kconfig.debug
>> +++ b/drivers/gpu/drm/Kconfig.debug
>> @@ -99,5 +99,17 @@ config DRM_TTM_KUNIT_TEST
>>   
>>   	  If in doubt, say "N".
>>   
>> +config DRM_SCHED_KUNIT_TEST
>> +	tristate "KUnit tests for the DRM scheduler" if
>> !KUNIT_ALL_TESTS
>> +	select DRM_SCHED
>> +	depends on DRM && KUNIT
>> +	default KUNIT_ALL_TESTS
>> +	help
>> +	  Choose this option to build unit tests for the DRM
>> scheduler.
>> +
>> +	  Recommended for driver developers only.
>> +
>> +	  If in doubt, say "N".
>> +
>>   config DRM_EXPORT_FOR_TESTS
>>   	bool
>> diff --git a/drivers/gpu/drm/scheduler/.kunitconfig
>> b/drivers/gpu/drm/scheduler/.kunitconfig
>> new file mode 100644
>> index 000000000000..cece53609fcf
>> --- /dev/null
>> +++ b/drivers/gpu/drm/scheduler/.kunitconfig
>> @@ -0,0 +1,12 @@
>> +CONFIG_KUNIT=y
>> +CONFIG_DRM=y
>> +CONFIG_DRM_SCHED_KUNIT_TEST=y
>> +CONFIG_EXPERT=y
>> +CONFIG_DEBUG_SPINLOCK=y
>> +CONFIG_DEBUG_MUTEXES=y
>> +CONFIG_DEBUG_ATOMIC_SLEEP=y
>> +CONFIG_LOCK_DEBUGGING_SUPPORT=y
>> +CONFIG_PROVE_LOCKING=y
>> +CONFIG_LOCKDEP=y
>> +CONFIG_DEBUG_LOCKDEP=y
>> +CONFIG_DEBUG_LIST=y
>> diff --git a/drivers/gpu/drm/scheduler/Makefile
>> b/drivers/gpu/drm/scheduler/Makefile
>> index 53863621829f..6e13e4c63e9d 100644
>> --- a/drivers/gpu/drm/scheduler/Makefile
>> +++ b/drivers/gpu/drm/scheduler/Makefile
>> @@ -23,3 +23,5 @@
>>   gpu-sched-y := sched_main.o sched_fence.o sched_entity.o
>>   
>>   obj-$(CONFIG_DRM_SCHED) += gpu-sched.o
>> +
>> +obj-$(CONFIG_DRM_SCHED_KUNIT_TEST) += tests/
>> diff --git a/drivers/gpu/drm/scheduler/tests/Makefile
>> b/drivers/gpu/drm/scheduler/tests/Makefile
>> new file mode 100644
>> index 000000000000..51d275a18cf4
>> --- /dev/null
>> +++ b/drivers/gpu/drm/scheduler/tests/Makefile
>> @@ -0,0 +1,6 @@
>> +
>> +drm-sched-tests-y := \
>> +        mock_scheduler.o \
>> +        tests_basic.o
>> +
>> +obj-$(CONFIG_DRM_SCHED_KUNIT_TEST) += drm-sched-tests.o
>> diff --git a/drivers/gpu/drm/scheduler/tests/mock_scheduler.c
>> b/drivers/gpu/drm/scheduler/tests/mock_scheduler.c
>> new file mode 100644
>> index 000000000000..d73a9f0337da
>> --- /dev/null
>> +++ b/drivers/gpu/drm/scheduler/tests/mock_scheduler.c
>> @@ -0,0 +1,317 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +
>> +#include "sched_tests.h"
>> +
>> +/*
>> + * Here we implement the mock "GPU" (or the scheduler backend) which
>> is used by
>> + * the DRM scheduler unit tests in order to exercise the core
>> functionality.
>> + *
>> + * Test cases are implemented in a separate file.
>> + */
>> +
>> +/**
>> + * drm_mock_new_sched_entity - Create a new mock scheduler entity
>> + *
>> + * @test: KUnit test owning the entity
>> + * @priority: Scheduling priority
>> + * @sched: Mock scheduler on which the entity can be scheduled
>> + *
>> + * Returns: New mock scheduler entity with allocation managed by the
>> test
>> + */
>> +struct drm_mock_sched_entity *
>> +drm_mock_new_sched_entity(struct kunit *test,
> 
> This naming seems to be inconsistent with its counterpart,
> drm_mock_sched_entity_free().
> 
> Better drm_mock_sched_entity_new()

Yes this is the only incosistent one and it was deliberate (somehow it 
read better to me when looking at the final code) but if you insist I 
can swap it around. Let me know.

> 
> 
>> +			  enum drm_sched_priority priority,
>> +			  struct drm_mock_scheduler *sched)
>> +{
>> +	struct drm_mock_sched_entity *entity;
>> +	struct drm_gpu_scheduler *drm_sched;
>> +	int ret;
>> +
>> +	entity = kunit_kzalloc(test, sizeof(*entity), GFP_KERNEL);
>> +	KUNIT_ASSERT_NOT_NULL(test, entity);
>> +
>> +	drm_sched = &sched->base;
>> +	ret = drm_sched_entity_init(&entity->base,
>> +				    priority,
>> +				    &drm_sched, 1,
>> +				    NULL);
>> +	KUNIT_ASSERT_EQ(test, ret, 0);
>> +
>> +	entity->test = test;
>> +
>> +	return entity;
>> +}
>> +
>> +/**
>> + * drm_mock_sched_entity_free - Destroys a mock scheduler entity
>> + *
>> + * @entity: Entity to destroy
>> + *
>> + * To be used from the test cases once done with the entity.
>> + */
>> +void drm_mock_sched_entity_free(struct drm_mock_sched_entity
>> *entity)
>> +{
>> +	drm_sched_entity_destroy(&entity->base);
>> +}
>> +
>> +static enum hrtimer_restart
>> +drm_mock_sched_job_signal_timer(struct hrtimer *hrtimer)
>> +{
>> +	struct drm_mock_sched_job *job =
>> +		container_of(hrtimer, typeof(*job), timer);
>> +	struct drm_mock_scheduler *sched =
>> +		drm_sched_to_mock_sched(job->base.sched);
>> +	struct drm_mock_sched_job *next;
>> +	ktime_t now = ktime_get();
>> +	unsigned long flags;
>> +	LIST_HEAD(signal);
>> +
>> +	spin_lock_irqsave(&sched->lock, flags);
>> +	list_for_each_entry_safe(job, next, &sched->job_list, link)
>> {
>> +		if (!job->duration_us)
>> +			break;
>> +
>> +		if (ktime_before(now, job->finish_at))
>> +			break;
>> +
>> +		list_move_tail(&job->link, &signal);
>> +		sched->hw_timeline.cur_seqno = job->hw_fence.seqno;
>> +	}
>> +	spin_unlock_irqrestore(&sched->lock, flags);
>> +
>> +	list_for_each_entry(job, &signal, link) {
>> +		dma_fence_signal(&job->hw_fence);
>> +		dma_fence_put(&job->hw_fence);
>> +	}
>> +
>> +	return HRTIMER_NORESTART;
>> +}
>> +
>> +/**
>> + * drm_mock_new_sched_job - Create a new mock scheduler job
>> + *
>> + * @test: KUnit test owning the job
>> + * @entity: Scheduler entity of the job
>> + *
>> + * Returns: New mock scheduler job with allocation managed by the
>> test
>> + */
>> +struct drm_mock_sched_job *
>> +drm_mock_new_sched_job(struct kunit *test,
> 
> IMO we could even think about establishing this style
> 
> return type stuff *
> function_foo()
> {
> 
> for all scheduler unit test files. Would always be consistent. WDYT?

I prefer a single line when it fits. I can change it, although in 
general I don't think being as strict on this detail is very important 
if that would be a rule applicable just to this sub-directory.

>> +		       struct drm_mock_sched_entity *entity)
>> +{
>> +	struct drm_mock_sched_job *job;
>> +	int ret;
>> +
>> +	job = kunit_kzalloc(test, sizeof(*job), GFP_KERNEL);
>> +	KUNIT_ASSERT_NOT_NULL(test, job);
>> +
>> +	ret = drm_sched_job_init(&job->base,
>> +				 &entity->base,
>> +				 1,
>> +				 NULL);
>> +	KUNIT_ASSERT_EQ(test, ret, 0);
>> +
>> +	job->test = test;
>> +
>> +	spin_lock_init(&job->lock);
>> +	INIT_LIST_HEAD(&job->link);
>> +	hrtimer_init(&job->timer, CLOCK_MONOTONIC,
>> HRTIMER_MODE_ABS);
>> +	job->timer.function = drm_mock_sched_job_signal_timer;
>> +
>> +	return job;
>> +}
>> +
>> +static const char *drm_mock_sched_hw_fence_driver_name(struct
>> dma_fence *fence)
> 
> here for example; see comment above.
> 
>> +{
>> +	return "drm_mock_sched";
>> +}
>> +
>> +static const char *
>> +drm_mock_sched_hw_fence_timeline_name(struct dma_fence *fence)
>> +{
>> +	struct drm_mock_sched_job *job =
>> +		container_of(fence, typeof(*job), hw_fence);
>> +
>> +	return (const char *)job->base.sched->name;
>> +}
>> +
>> +static void drm_mock_sched_hw_fence_release(struct dma_fence *fence)
>> +{
>> +	struct drm_mock_sched_job *job =
>> +		container_of(fence, typeof(*job), hw_fence);
>> +
>> +	hrtimer_cancel(&job->timer);
>> +
>> +	/* Freed by the kunit framework */
>> +}
>> +
>> +static const struct dma_fence_ops drm_mock_sched_hw_fence_ops = {
>> +	.get_driver_name = drm_mock_sched_hw_fence_driver_name,
>> +	.get_timeline_name = drm_mock_sched_hw_fence_timeline_name,
>> +	.release = drm_mock_sched_hw_fence_release,
>> +};
>> +
>> +static struct dma_fence *mock_sched_run_job(struct drm_sched_job
>> *sched_job)
>> +{
>> +	struct drm_mock_scheduler *sched =
>> +		drm_sched_to_mock_sched(sched_job->sched);
>> +	struct drm_mock_sched_job *job =
>> drm_sched_job_to_mock_job(sched_job);
>> +
>> +	dma_fence_init(&job->hw_fence,
>> +		       &drm_mock_sched_hw_fence_ops,
>> +		       &job->lock,
>> +		       sched->hw_timeline.context,
>> +		       atomic_inc_return(&sched-
>>> hw_timeline.next_seqno));
>> +
>> +	dma_fence_get(&job->hw_fence); /* Reference for the job_list
>> */
>> +
>> +	spin_lock_irq(&sched->lock);
>> +	if (job->duration_us) {
>> +		ktime_t prev_finish_at = 0;
>> +
>> +		if (!list_empty(&sched->job_list)) {
>> +			struct drm_mock_sched_job *prev =
>> +				list_last_entry(&sched->job_list,
>> typeof(*prev),
>> +						link);
>> +
>> +			prev_finish_at = prev->finish_at;
>> +		}
>> +
>> +		if (!prev_finish_at)
>> +			prev_finish_at = ktime_get();
>> +
>> +		job->finish_at = ktime_add_us(prev_finish_at, job-
>>> duration_us);
>> +	}
>> +	list_add_tail(&job->link, &sched->job_list);
>> +	if (job->finish_at)
>> +		hrtimer_start(&job->timer, job->finish_at,
>> HRTIMER_MODE_ABS);
>> +	spin_unlock_irq(&sched->lock);
>> +
>> +	return &job->hw_fence;
>> +}
>> +
>> +static enum drm_gpu_sched_stat
>> +mock_sched_timedout_job(struct drm_sched_job *sched_job)
>> +{
>> +	return DRM_GPU_SCHED_STAT_ENODEV;
>> +}
>> +
>> +static void mock_sched_free_job(struct drm_sched_job *sched_job)
>> +{
>> +	drm_sched_job_cleanup(sched_job);
>> +}
>> +
>> +static const struct drm_sched_backend_ops drm_mock_scheduler_ops = {
>> +	.run_job = mock_sched_run_job,
>> +	.timedout_job = mock_sched_timedout_job,
>> +	.free_job = mock_sched_free_job
>> +};
>> +
>> +/**
>> + * drm_mock_new_scheduler - Create a new mock scheduler
>> + *
>> + * @test: KUnit test owning the job
>> + *
>> + * Returns: New mock scheduler with allocation managed by the test
>> + */
>> +struct drm_mock_scheduler *drm_mock_new_scheduler(struct kunit
>> *test)
>> +{
>> +	struct drm_sched_init_args args = {
>> +		.ops		= &drm_mock_scheduler_ops,
>> +		.num_rqs	= DRM_SCHED_PRIORITY_COUNT,
>> +		.credit_limit	= U32_MAX,
>> +		.hang_limit	= UINT_MAX,
>> +		.timeout	= MAX_SCHEDULE_TIMEOUT,
>> +		.name		= "drm-mock-scheduler",
>> +	};
>> +	struct drm_mock_scheduler *sched;
>> +	int ret;
>> +
>> +	sched = kunit_kzalloc(test, sizeof(*sched), GFP_KERNEL);
>> +	KUNIT_ASSERT_NOT_NULL(test, sched);
>> +
>> +	ret = drm_sched_init(&sched->base, &args);
>> +	KUNIT_ASSERT_EQ(test, ret, 0);
>> +
>> +	sched->test = test;
>> +	sched->hw_timeline.context = dma_fence_context_alloc(1);
>> +	atomic_set(&sched->hw_timeline.next_seqno, 0);
>> +	INIT_LIST_HEAD(&sched->job_list);
>> +	spin_lock_init(&sched->lock);
>> +
>> +	return sched;
>> +}
>> +
>> +/**
>> + * drm_mock_scheduler_fini - Destroys a mock scheduler
>> + *
>> + * @sched: Scheduler to destroy
>> + *
>> + * To be used from the test cases once done with the scheduler.
>> + */
>> +void drm_mock_scheduler_fini(struct drm_mock_scheduler *sched)
>> +{
>> +	struct drm_mock_sched_job *job, *next;
>> +	unsigned long flags;
>> +	LIST_HEAD(signal);
>> +
>> +	spin_lock_irqsave(&sched->lock, flags);
>> +	list_for_each_entry_safe(job, next, &sched->job_list, link)
>> +		list_move_tail(&job->link, &signal);
>> +	spin_unlock_irqrestore(&sched->lock, flags);
>> +
>> +	list_for_each_entry(job, &signal, link) {
>> +		hrtimer_cancel(&job->timer);
>> +		dma_fence_put(&job->hw_fence);
>> +	}
>> +
>> +	drm_sched_fini(&sched->base);
>> +}
>> +
>> +/**
>> + * drm_mock_sched_advance - Advances the mock scheduler timeline
>> + *
>> + * @sched: Scheduler timeline to advance
>> + * @num: By how many jobs to advance
>> + *
>> + * Advancing the scheduler timeline by a number of seqnos will
>> trigger
>> + * signalling of the hardware fences and unlinking the jobs from the
>> internal
>> + * scheduler tracking.
>> + *
>> + * This can be used from test cases which want complete control of
>> the simulated
>> + * job execution timing. For example submitting one job with no set
>> duration
>> + * would never complete it before test cases advances the timeline
>> by one.
>> + */
>> +unsigned int drm_mock_sched_advance(struct drm_mock_scheduler
>> *sched,
>> +				    unsigned int num)
>> +{
>> +	struct drm_mock_sched_job *job, *next;
>> +	unsigned int found = 0;
>> +	unsigned long flags;
>> +	LIST_HEAD(signal);
>> +
>> +	spin_lock_irqsave(&sched->lock, flags);
>> +	if (WARN_ON_ONCE(sched->hw_timeline.cur_seqno + num <
>> +			 sched->hw_timeline.cur_seqno))
>> +		goto unlock;
>> +	sched->hw_timeline.cur_seqno += num;
>> +	list_for_each_entry_safe(job, next, &sched->job_list, link)
>> {
>> +		if (sched->hw_timeline.cur_seqno < job-
>>> hw_fence.seqno)
>> +			break;
>> +
>> +		list_move_tail(&job->link, &signal);
>> +		found++;
>> +	}
>> +unlock:
>> +	spin_unlock_irqrestore(&sched->lock, flags);
>> +
>> +	list_for_each_entry(job, &signal, link) {
>> +		dma_fence_signal(&job->hw_fence);
>> +		dma_fence_put(&job->hw_fence);
>> +	}
>> +
>> +	return found;
>> +}
>> +
>> +MODULE_DESCRIPTION("DRM mock scheduler and tests");
>> +MODULE_LICENSE("GPL");
>> diff --git a/drivers/gpu/drm/scheduler/tests/sched_tests.h
>> b/drivers/gpu/drm/scheduler/tests/sched_tests.h
>> new file mode 100644
>> index 000000000000..0614bc901dd1
>> --- /dev/null
>> +++ b/drivers/gpu/drm/scheduler/tests/sched_tests.h
>> @@ -0,0 +1,218 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +
>> +#ifndef _SCHED_TESTS_H_
>> +#define _SCHED_TESTS_H_
>> +
>> +#include <kunit/test.h>
>> +#include <linux/atomic.h>
>> +#include <linux/dma-fence.h>
>> +#include <linux/hrtimer.h>
>> +#include <linux/ktime.h>
>> +#include <linux/list.h>
>> +#include <linux/atomic.h>
>> +#include <linux/mutex.h>
>> +#include <linux/types.h>
>> +
>> +#include <drm/gpu_scheduler.h>
>> +
>> +/*
>> + * DOC: Mock DRM scheduler data structures
>> + *
>> + * drm_mock_* data structures are used to implement a mock "GPU".
>> + *
>> + * They subclass the core DRM scheduler objects and add their data
>> on top, which
>> + * enables tracking the submitted jobs and simulating their
>> execution with the
>> + * attributes as specified by the test case.
>> + */
>> +
>> +/**
>> + * struct drm_mock_scheduler - implements a trivial mock GPU
>> execution engine
>> + *
>> + * @base: DRM scheduler base class
>> + * @test: Backpointer to owning the kunit test case
>> + * @lock: Lock to protect the simulated @hw_timeline and the
>> @job_list
>> + * @job_list: List of jobs submitted to the mock GPU
>> + * @hw_timeline: Simulated hardware timeline has a @context,
>> @next_seqno and
>> + *		 @cur_seqno for implementing a struct dma_fence
>> signaling the
>> + *		 simulated job completion.
>> + *
>> + * Trivial mock GPU execution engine tracks submitted jobs and
>> enables
>> + * completing them strictly in submission order.
>> + */
>> +struct drm_mock_scheduler {
>> +	struct drm_gpu_scheduler base;
>> +
>> +	struct kunit		*test;
>> +
>> +	spinlock_t		lock;
>> +	struct list_head	job_list;
>> +
>> +	struct {
>> +		u64		context;
>> +		atomic_t	next_seqno;
>> +		unsigned int	cur_seqno;
>> +	} hw_timeline;
>> +};
>> +
>> +/**
>> + * struct drm_mock_sched_entity - implements a mock GPU sched entity
>> + *
>> + * @base: DRM scheduler entity base class
>> + * @test: Backpointer to owning the kunit test case
>> + *
>> + * Mock GPU sched entity is used by the test cases to submit jobs to
>> the mock
>> + * scheduler.
>> + */
>> +struct drm_mock_sched_entity {
>> +	struct drm_sched_entity base;
>> +
>> +	struct kunit		*test;
>> +};
>> +
>> +/**
>> + * struct drm_mock_sched_job - implements a mock GPU job
>> + *
>> + * @base: DRM sched job base class
>> + * @link: List head element used by job tracking by the
>> drm_mock_scheduler
>> + * @timer: Timer used for simulating job execution duration
>> + * @duration_us: Simulated job duration in micro seconds, or zero if
>> in manual
>> + *		 timeline advance mode
>> + * @finish_at: Absolute time when the jobs with set duration will
>> complete
>> + * @lock: Lock used for @hw_fence
>> + * @hw_fence: Fence returned to DRM scheduler as the hardware fence
> 
> Can you ellaborate a bit more about lock's purpose (here in the thread
> at first)?
> 
> The hw_fence has its own internal lock for adding callbacks and the
> like, so why is this one here necessary?

It _is_ the internal fence lock, the one that is passed to dma_fence_init().

> Furthermore, at least in this patch here, it seems that whenever
> hw_fence is changed, its being protected by the scheduler's lock. Why
> is that?

I don't follow - what do you consider "hw_fence is changed"?

Hw_fence is initialized in the ->run_job() callback and is signalled 
outside the mock_sched->lock.

> 
>> + * @test: Backpointer to owning the kunit test case
>> + *
>> + * Mock GPU sched job is used by the test cases to submit jobs to
>> the mock
>> + * scheduler.
>> + */
>> +struct drm_mock_sched_job {
>> +	struct drm_sched_job	base;
>> +
>> +	struct list_head	link;
>> +	struct hrtimer		timer;
>> +
>> +	unsigned int		duration_us;
>> +	ktime_t			finish_at;
>> +
>> +	spinlock_t		lock;
>> +	struct dma_fence	hw_fence;
>> +
>> +	struct kunit		*test;
>> +};
>> +
>> +static inline struct drm_mock_scheduler *
>> +drm_sched_to_mock_sched(struct drm_gpu_scheduler *sched)
>> +{
>> +	return container_of(sched, struct drm_mock_scheduler, base);
>> +};
>> +
>> +static inline struct drm_mock_sched_entity *
>> +drm_sched_entity_to_mock_entity(struct drm_sched_entity
>> *sched_entity)
>> +{
>> +	return container_of(sched_entity, struct
>> drm_mock_sched_entity, base);
>> +};
>> +
>> +static inline struct drm_mock_sched_job *
>> +drm_sched_job_to_mock_job(struct drm_sched_job *sched_job)
>> +{
>> +	return container_of(sched_job, struct drm_mock_sched_job,
>> base);
>> +};
>> +
>> +struct drm_mock_scheduler *drm_mock_new_scheduler(struct kunit
>> *test);
>> +void drm_mock_scheduler_fini(struct drm_mock_scheduler *sched);
>> +unsigned int drm_mock_sched_advance(struct drm_mock_scheduler
>> *sched,
>> +				    unsigned int num);
>> +
>> +struct drm_mock_sched_entity *
>> +drm_mock_new_sched_entity(struct kunit *test,
>> +			  enum drm_sched_priority priority,
>> +			  struct drm_mock_scheduler *sched);
>> +void drm_mock_sched_entity_free(struct drm_mock_sched_entity
>> *entity);
>> +
>> +struct drm_mock_sched_job *
>> +drm_mock_new_sched_job(struct kunit *test,
>> +		       struct drm_mock_sched_entity *entity);
>> +
>> +/**
>> + * drm_mock_sched_job_submit - Arm and submit a job in one go
>> + *
>> + * @job: Job to arm and submit
>> + */
>> +static inline void drm_mock_sched_job_submit(struct
>> drm_mock_sched_job *job)
>> +{
>> +	drm_sched_job_arm(&job->base);
>> +	drm_sched_entity_push_job(&job->base);
>> +}
>> +
>> +/**
>> + * drm_mock_sched_job_set_duration_us - Set a job duration
>> + *
>> + * @job: Job to set the duration for
>> + * @duration_us: Duration in micro seconds
>> + *
>> + * Jobs with duration set will be automatically completed by the
>> mock scheduler
>> + * as the timeline progress, unless a job without a set duration is
> 
> s/progress/progresses
> 
>> encountered
>> + * in the timelime in which case calling drm_mock_sched_advance will
> 
> s/drm_mock_sched_advance/drm_mock_sched_advanace()
> 
> As I learned recently, the brackets are what actually teaches the doc
> generator that this is a function that shall be linked in the docu.

Both done.

> 
>> be required
>> + * to bump the timeline.
>> + */
>> +static inline void
>> +drm_mock_sched_job_set_duration_us(struct drm_mock_sched_job *job,
>> +				   unsigned int duration_us)
>> +{
>> +	job->duration_us = duration_us;
>> +}
>> +
>> +/**
>> + * drm_mock_sched_job_is_finished - Check if a job is finished
>> + *
>> + * @job: Job to check
>> + *
>> + * Returns: true if finished
>> + */
>> +static inline bool
>> +drm_mock_sched_job_is_finished(struct drm_mock_sched_job *job)
>> +{
>> +	return dma_fence_is_signaled(&job->base.s_fence->finished);
>> +}
>> +
>> +/**
>> + * drm_mock_sched_job_wait_finished - Wait until a job is finished
>> + *
>> + * @job: Job to wait for
>> + * @timeout: Wait time in jiffies
>> + *
>> + * Returns: true if finished within the timeout provided, otherwise
>> false
>> + */
>> +static inline bool
>> +drm_mock_sched_job_wait_finished(struct drm_mock_sched_job *job,
>> long timeout)
>> +{
>> +	long ret;
>> +
>> +	ret = dma_fence_wait_timeout(&job->base.s_fence->finished,
>> +				     false,
>> +				     timeout);
>> +
>> +	return ret != 0;
>> +}
>> +
>> +/**
>> + * drm_mock_sched_job_wait_finished - Wait until a job is scheduled
>> + *
>> + * @job: Job to wait for
>> + * @timeout: Wait time in jiffies
>> + *
>> + * Returns: true if scheduled within the timeout provided, otherwise
>> false
>> + */
>> +static inline long
>> +drm_mock_sched_job_wait_scheduled(struct drm_mock_sched_job *job,
>> long timeout)
>> +{
>> +	long ret;
>> +
>> +	ret = dma_fence_wait_timeout(&job->base.s_fence->scheduled,
>> +				     false,
>> +				     timeout);
>> +
>> +	return ret != 0;
>> +}
>> +
>> +#endif
>> diff --git a/drivers/gpu/drm/scheduler/tests/tests_basic.c
>> b/drivers/gpu/drm/scheduler/tests/tests_basic.c
>> new file mode 100644
>> index 000000000000..c12368a22a39
>> --- /dev/null
>> +++ b/drivers/gpu/drm/scheduler/tests/tests_basic.c
>> @@ -0,0 +1,197 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +
>> +#include "sched_tests.h"
>> +
>> +/*
>> + * DRM scheduler basic tests should check the basic functional
>> correctness of
>> + * the scheduler, including some very light smoke testing. More
>> targeted tests,
>> + * for example focusing on testing specific bugs and other more
>> complicated test
>> + * scenarios, should be implemented in a separate source units.
> 
> s/a//

Done.

> 
>> + */
>> +
>> +static int drm_sched_basic_init(struct kunit *test)
>> +{
>> +	test->priv = drm_mock_new_scheduler(test);
>> +
>> +	return 0;
>> +}
>> +
>> +static void drm_sched_basic_exit(struct kunit *test)
>> +{
>> +	struct drm_mock_scheduler *sched = test->priv;
>> +
>> +	drm_mock_scheduler_fini(sched);
>> +}
>> +
>> +static void drm_sched_basic_submit(struct kunit *test)
>> +{
>> +	struct drm_mock_scheduler *sched = test->priv;
>> +	struct drm_mock_sched_entity *entity;
>> +	struct drm_mock_sched_job *job;
>> +	unsigned int i;
>> +	bool done;
>> +
>> +	/*
>> +	 * Submit one job to the scheduler and verify that it gets
>> scheduled
>> +	 * and completed only when the mock hw backend processes it.
>> +	 */
> 
> That seems to be the description of the entire function? If yes, we
> probably want it above the function's begin.

I find it more useful closer to the action so would prefer to keep it as 
is. But if you insist I can move.

Regards,

Tvrtko

> 
> 
> Thx
> P.
> 
>> +
>> +	entity = drm_mock_new_sched_entity(test,
>> +					
>> DRM_SCHED_PRIORITY_NORMAL,
>> +					   sched);
>> +	job = drm_mock_new_sched_job(test, entity);
>> +
>> +	drm_mock_sched_job_submit(job);
>> +
>> +	done = drm_mock_sched_job_wait_scheduled(job, HZ);
>> +	KUNIT_ASSERT_EQ(test, done, true);
>> +
>> +	done = drm_mock_sched_job_wait_finished(job, HZ / 2);
>> +	KUNIT_ASSERT_EQ(test, done, false);
>> +
>> +	i = drm_mock_sched_advance(sched, 1);
>> +	KUNIT_ASSERT_EQ(test, i, 1);
>> +
>> +	done = drm_mock_sched_job_wait_finished(job, HZ);
>> +	KUNIT_ASSERT_EQ(test, done, true);
>> +
>> +	drm_mock_sched_entity_free(entity);
>> +}
>> +
>> +struct drm_sched_basic_params {
>> +	const char *description;
>> +	unsigned int queue_depth;
>> +	unsigned int num_entities;
>> +	unsigned int job_us;
>> +	bool dep_chain;
>> +};
>> +
>> +static const struct drm_sched_basic_params drm_sched_basic_cases[] =
>> {
>> +	{
>> +		.description = "A queue of jobs in a single entity",
>> +		.queue_depth = 100,
>> +		.job_us = 1000,
>> +		.num_entities = 1,
>> +	},
>> +	{
>> +		.description = "A chain of dependent jobs across
>> multiple entities",
>> +		.queue_depth = 100,
>> +		.job_us = 1000,
>> +		.num_entities = 1,
>> +		.dep_chain = true,
>> +	},
>> +	{
>> +		.description = "Multiple independent job queues",
>> +		.queue_depth = 100,
>> +		.job_us = 1000,
>> +		.num_entities = 4,
>> +	},
>> +	{
>> +		.description = "Multiple inter-dependent job
>> queues",
>> +		.queue_depth = 100,
>> +		.job_us = 1000,
>> +		.num_entities = 4,
>> +		.dep_chain = true,
>> +	},
>> +};
>> +
>> +static void
>> +drm_sched_basic_desc(const struct drm_sched_basic_params *params,
>> char *desc)
>> +{
>> +	strscpy(desc, params->description, KUNIT_PARAM_DESC_SIZE);
>> +}
>> +
>> +KUNIT_ARRAY_PARAM(drm_sched_basic, drm_sched_basic_cases,
>> drm_sched_basic_desc);
>> +
>> +static void drm_sched_basic_test(struct kunit *test)
>> +{
>> +	const struct drm_sched_basic_params *params = test-
>>> param_value;
>> +	struct drm_mock_scheduler *sched = test->priv;
>> +	struct drm_mock_sched_job *job, *prev = NULL;
>> +	struct drm_mock_sched_entity **entity;
>> +	unsigned int i, cur_ent = 0;
>> +	bool done;
>> +
>> +	entity = kunit_kcalloc(test, params->num_entities,
>> sizeof(*entity),
>> +			       GFP_KERNEL);
>> +	KUNIT_ASSERT_NOT_NULL(test, entity);
>> +
>> +	for (i = 0; i < params->num_entities; i++)
>> +		entity[i] = drm_mock_new_sched_entity(test,
>> +						
>> DRM_SCHED_PRIORITY_NORMAL,
>> +						      sched);
>> +
>> +	for (i = 0; i < params->queue_depth; i++) {
>> +		job = drm_mock_new_sched_job(test,
>> entity[cur_ent++]);
>> +		cur_ent %= params->num_entities;
>> +		drm_mock_sched_job_set_duration_us(job, params-
>>> job_us);
>> +		if (params->dep_chain && prev)
>> +			drm_sched_job_add_dependency(&job->base,
>> +						
>> dma_fence_get(&prev->base.s_fence->finished));
>> +		drm_mock_sched_job_submit(job);
>> +		prev = job;
>> +	}
>> +
>> +	done = drm_mock_sched_job_wait_finished(job, HZ);
>> +	KUNIT_ASSERT_EQ(test, done, true);
>> +
>> +	for (i = 0; i < params->num_entities; i++)
>> +		drm_mock_sched_entity_free(entity[i]);
>> +}
>> +
>> +static void drm_sched_basic_entity_cleanup(struct kunit *test)
>> +{
>> +	struct drm_mock_sched_job *job, *mid, *prev = NULL;
>> +	struct drm_mock_scheduler *sched = test->priv;
>> +	struct drm_mock_sched_entity *entity[4];
>> +	const unsigned int qd = 100;
>> +	unsigned int i, cur_ent = 0;
>> +	bool done;
>> +
>> +	/*
>> +	 * Submit a queue of jobs across different entities with an
>> explicit
>> +	 * chain of dependencies between them and trigger entity
>> cleanup while
>> +	 * the queue is still being processed.
>> +	 */
>> +
>> +	for (i = 0; i < ARRAY_SIZE(entity); i++)
>> +		entity[i] = drm_mock_new_sched_entity(test,
>> +						
>> DRM_SCHED_PRIORITY_NORMAL,
>> +						      sched);
>> +
>> +	for (i = 0; i < qd; i++) {
>> +		job = drm_mock_new_sched_job(test,
>> entity[cur_ent++]);
>> +		cur_ent %= ARRAY_SIZE(entity);
>> +		drm_mock_sched_job_set_duration_us(job, 1000);
>> +		if (prev)
>> +			drm_sched_job_add_dependency(&job->base,
>> +						
>> dma_fence_get(&prev->base.s_fence->finished));
>> +		drm_mock_sched_job_submit(job);
>> +		if (i == qd / 2)
>> +			mid = job;
>> +		prev = job;
>> +	}
>> +
>> +	done = drm_mock_sched_job_wait_finished(mid, HZ);
>> +	KUNIT_ASSERT_EQ(test, done, true);
>> +
>> +	/* Exit with half of the queue still pending to be executed.
>> */
>> +	for (i = 0; i < ARRAY_SIZE(entity); i++)
>> +		drm_mock_sched_entity_free(entity[i]);
>> +}
>> +
>> +static struct kunit_case drm_sched_basic_tests[] = {
>> +	KUNIT_CASE(drm_sched_basic_submit),
>> +	KUNIT_CASE_PARAM(drm_sched_basic_test,
>> drm_sched_basic_gen_params),
>> +	KUNIT_CASE(drm_sched_basic_entity_cleanup),
>> +	{}
>> +};
>> +
>> +static struct kunit_suite drm_sched_basic = {
>> +	.name = "drm_sched_basic_tests",
>> +	.init = drm_sched_basic_init,
>> +	.exit = drm_sched_basic_exit,
>> +	.test_cases = drm_sched_basic_tests,
>> +};
>> +
>> +kunit_test_suite(drm_sched_basic);
> 



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