Re: [Intel-xe] [PATCH v2 05/31] drm/xe: Long running job update

["Thomas Hellström" <thomas.hellstrom@linux.intel.com>]

On 5/9/23 16:56, Matthew Brost wrote:
> On Mon, May 08, 2023 at 03:14:10PM +0200, Thomas Hellström wrote:
>> Hi, Matthew
>>
>> In addition to Rodrigo's comments:
>>
>> On 5/2/23 02:17, Matthew Brost wrote:
>>> Flow control + write ring in exec, return NULL in run_job, siganl
>>> xe_hw_fence immediately, and override TDR for LR jobs.
>>>
>>> Signed-off-by: Matthew Brost <matthew.brost@intel.com>
>>> ---
>>>    drivers/gpu/drm/xe/xe_engine.c           | 32 ++++++++
>>>    drivers/gpu/drm/xe/xe_engine.h           |  4 +
>>>    drivers/gpu/drm/xe/xe_exec.c             |  8 ++
>>>    drivers/gpu/drm/xe/xe_guc_engine_types.h |  2 +
>>>    drivers/gpu/drm/xe/xe_guc_submit.c       | 95 +++++++++++++++++++++---
>>>    drivers/gpu/drm/xe/xe_trace.h            |  5 ++
>>>    6 files changed, 137 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/xe/xe_engine.c b/drivers/gpu/drm/xe/xe_engine.c
>>> index 094ec17d3004..d1e84d7adbd4 100644
>>> --- a/drivers/gpu/drm/xe/xe_engine.c
>>> +++ b/drivers/gpu/drm/xe/xe_engine.c
>>> @@ -18,6 +18,7 @@
>>>    #include "xe_macros.h"
>>>    #include "xe_migrate.h"
>>>    #include "xe_pm.h"
>>> +#include "xe_ring_ops_types.h"
>>>    #include "xe_trace.h"
>>>    #include "xe_vm.h"
>>> @@ -673,6 +674,37 @@ static void engine_kill_compute(struct xe_engine *e)
>>>    	up_write(&e->vm->lock);
>>>    }
>>> +/**
>>> + * xe_engine_is_lr() - Whether an engine is long-running
>>> + * @e: The engine
>>> + *
>>> + * Return: True if the engine is long-running, false otherwise.
>>> + */
>>> +bool xe_engine_is_lr(struct xe_engine *e)
>>> +{
>>> +	return e->vm && xe_vm_no_dma_fences(e->vm) &&
>>> +		!(e->flags & ENGINE_FLAG_VM);
>>> +}
>>> +
>>> +static s32 xe_engine_num_job_inflight(struct xe_engine *e)
>>> +{
>>> +	return e->lrc->fence_ctx.next_seqno - xe_lrc_seqno(e->lrc) - 1;
>>> +}
>>> +
>>> +/**
>>> + * xe_engine_ring_full() - Whether an engine's ring is full
>>> + * @e: The engine
>>> + *
>>> + * Return: True if the engine's ring is full, false otherwise.
>>> + */
>>> +bool xe_engine_ring_full(struct xe_engine *e)
>>> +{
>>> +	struct xe_lrc *lrc = e->lrc;
>>> +	s32 max_job = lrc->ring.size / MAX_JOB_SIZE_BYTES;
>>> +
>>> +	return xe_engine_num_job_inflight(e) >= max_job;
>>> +}
>>> +
>>>    /**
>>>     * xe_engine_is_idle() - Whether an engine is idle.
>>>     * @engine: The engine
>>> diff --git a/drivers/gpu/drm/xe/xe_engine.h b/drivers/gpu/drm/xe/xe_engine.h
>>> index a49cf2ab405e..2e60f6d90226 100644
>>> --- a/drivers/gpu/drm/xe/xe_engine.h
>>> +++ b/drivers/gpu/drm/xe/xe_engine.h
>>> @@ -42,6 +42,10 @@ static inline bool xe_engine_is_parallel(struct xe_engine *engine)
>>>    	return engine->width > 1;
>>>    }
>>> +bool xe_engine_is_lr(struct xe_engine *e);
>>> +
>>> +bool xe_engine_ring_full(struct xe_engine *e);
>>> +
>>>    bool xe_engine_is_idle(struct xe_engine *engine);
>>>    void xe_engine_kill(struct xe_engine *e);
>>> diff --git a/drivers/gpu/drm/xe/xe_exec.c b/drivers/gpu/drm/xe/xe_exec.c
>>> index ea869f2452ef..44ea9bcd0066 100644
>>> --- a/drivers/gpu/drm/xe/xe_exec.c
>>> +++ b/drivers/gpu/drm/xe/xe_exec.c
>>> @@ -13,6 +13,7 @@
>>>    #include "xe_device.h"
>>>    #include "xe_engine.h"
>>>    #include "xe_macros.h"
>>> +#include "xe_ring_ops_types.h"
>>>    #include "xe_sched_job.h"
>>>    #include "xe_sync.h"
>>>    #include "xe_vm.h"
>>> @@ -277,6 +278,11 @@ int xe_exec_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
>>>    		goto err_engine_end;
>>>    	}
>>> +	if (xe_engine_is_lr(engine) && xe_engine_ring_full(engine)) {
>>> +		err = -EWOULDBLOCK;
>>> +		goto err_engine_end;
>>> +	}
>>> +
>>>    	job = xe_sched_job_create(engine, xe_engine_is_parallel(engine) ?
>>>    				  addresses : &args->address);
>>>    	if (IS_ERR(job)) {
>>> @@ -363,6 +369,8 @@ int xe_exec_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
>>>    		xe_sync_entry_signal(&syncs[i], job,
>>>    				     &job->drm.s_fence->finished);
>>> +	if (xe_engine_is_lr(engine))
>>> +		engine->ring_ops->emit_job(job);
>>>    	xe_sched_job_push(job);
>>>    	xe_vm_reactivate_rebind(vm);
>>> diff --git a/drivers/gpu/drm/xe/xe_guc_engine_types.h b/drivers/gpu/drm/xe/xe_guc_engine_types.h
>>> index cbfb13026ec1..5d83132034a6 100644
>>> --- a/drivers/gpu/drm/xe/xe_guc_engine_types.h
>>> +++ b/drivers/gpu/drm/xe/xe_guc_engine_types.h
>>> @@ -31,6 +31,8 @@ struct xe_guc_engine {
>>>    	 */
>>>    #define MAX_STATIC_MSG_TYPE	3
>>>    	struct drm_sched_msg static_msgs[MAX_STATIC_MSG_TYPE];
>>> +	/** @lr_tdr: long running TDR worker */
>>> +	struct work_struct lr_tdr;
>>>    	/** @fini_async: do final fini async from this worker */
>>>    	struct work_struct fini_async;
>>>    	/** @resume_time: time of last resume */
>>> diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c
>>> index 68d09e7a4cc0..0a41f5d04f6d 100644
>>> --- a/drivers/gpu/drm/xe/xe_guc_submit.c
>>> +++ b/drivers/gpu/drm/xe/xe_guc_submit.c
>>> @@ -500,6 +500,14 @@ static void register_engine(struct xe_engine *e)
>>>    		parallel_write(xe, map, wq_desc.wq_status, WQ_STATUS_ACTIVE);
>>>    	}
>>> +	/*
>>> +	 * We must keep a reference for LR engines if engine is registered with
>>> +	 * the GuC as jobs signal immediately and can't destroy an engine if the
>>> +	 * GuC has a reference to it.
>>> +	 */
>>> +	if (xe_engine_is_lr(e))
>>> +		xe_engine_get(e);
>>> +
>>>    	set_engine_registered(e);
>>>    	trace_xe_engine_register(e);
>>>    	if (xe_engine_is_parallel(e))
>>> @@ -662,6 +670,7 @@ guc_engine_run_job(struct drm_sched_job *drm_job)
>>>    {
>>>    	struct xe_sched_job *job = to_xe_sched_job(drm_job);
>>>    	struct xe_engine *e = job->engine;
>>> +	bool lr = xe_engine_is_lr(e);
>>>    	XE_BUG_ON((engine_destroyed(e) || engine_pending_disable(e)) &&
>>>    		  !engine_banned(e) && !engine_suspended(e));
>>> @@ -671,14 +680,19 @@ guc_engine_run_job(struct drm_sched_job *drm_job)
>>>    	if (!engine_killed_or_banned(e) && !xe_sched_job_is_error(job)) {
>>>    		if (!engine_registered(e))
>>>    			register_engine(e);
>>> -		e->ring_ops->emit_job(job);
>>> +		if (!lr)	/* Written in IOCTL */
>> Hmm? What does "Written in IOCTL mean?" Could you rephrase to something more
>> descriptive?
>>
> "LR jos are emitted in the IOCTL"

Ah, I read it as "the lr variable was written in IOCTL."

Perhaps LR jobs are already emitted at execbuf time?

/Thomas


>
> Does that work?
>
> Matt
>
>>> +			e->ring_ops->emit_job(job);
>>>    		submit_engine(e);
>>>    	}
>>> -	if (test_and_set_bit(JOB_FLAG_SUBMIT, &job->fence->flags))
>>> +	if (lr) {
>>> +		xe_sched_job_set_error(job, -ENOTSUPP);
>>> +		return NULL;
>>> +	} else if (test_and_set_bit(JOB_FLAG_SUBMIT, &job->fence->flags)) {
>>>    		return job->fence;
>>> -	else
>>> +	} else {
>>>    		return dma_fence_get(job->fence);
>>> +	}
>>>    }
>>>    static void guc_engine_free_job(struct drm_sched_job *drm_job)
>>> @@ -782,6 +796,57 @@ static void simple_error_capture(struct xe_engine *e)
>>>    }
>>>    #endif
>>> +static void xe_guc_engine_trigger_cleanup(struct xe_engine *e)
>>> +{
>>> +	struct xe_guc *guc = engine_to_guc(e);
>>> +
>>> +	if (xe_engine_is_lr(e))
>>> +		queue_work(guc_to_gt(guc)->ordered_wq, &e->guc->lr_tdr);
>>> +	else
>>> +		drm_sched_set_timeout(&e->guc->sched, MIN_SCHED_TIMEOUT);
>>> +}
>>> +
>>> +static void xe_guc_engine_lr_cleanup(struct work_struct *w)
>>> +{
>>> +	struct xe_guc_engine *ge =
>>> +		container_of(w, struct xe_guc_engine, lr_tdr);
>>> +	struct xe_engine *e = ge->engine;
>>> +	struct drm_gpu_scheduler *sched = &ge->sched;
>>> +
>>> +	XE_BUG_ON(!xe_engine_is_lr(e));
>>> +	trace_xe_engine_lr_cleanup(e);
>>> +
>>> +	/* Kill the run_job / process_msg entry points */
>>> +	drm_sched_run_wq_stop(sched);
>>> +
>>> +	/* Engine state now stable, disable scheduling / deregister if needed */
>>> +	if (engine_registered(e)) {
>>> +		struct xe_guc *guc = engine_to_guc(e);
>>> +		int ret;
>>> +
>>> +		set_engine_banned(e);
>>> +		xe_engine_get(e);
>>> +		disable_scheduling_deregister(guc, e);
>>> +
>>> +		/*
>>> +		 * Must wait for scheduling to be disabled before signalling
>>> +		 * any fences, if GT broken the GT reset code should signal us.
>>> +		 */
>>> +		smp_rmb();
>> wait_event() paired with wake_up() family of functions typically set the
>> necessary barriers to make sure anything written prior to wake_up() is seen
>> in wait_event(). So that smp_rmb() is most likely not needed. If it still
>> is, its pairing smp_wmb() should be documented and pointed to as well. See
>> documentation of set_current_state() vs __set_current_state().
>>
>>> +		ret = wait_event_timeout(guc->ct.wq,
>>> +					 !engine_pending_disable(e) ||
>>> +					 guc_read_stopped(guc), HZ * 5);
>>> +		if (!ret) {
>>> +			XE_WARN_ON("Schedule disable failed to respond");
>>> +			drm_sched_run_wq_start(sched);
>>> +			xe_gt_reset_async(e->gt);
>>> +			return;
>>> +		}
>>> +	}
>>> +
>>> +	drm_sched_run_wq_start(sched);
>>> +}
>>> +
>>>    static enum drm_gpu_sched_stat
>>>    guc_engine_timedout_job(struct drm_sched_job *drm_job)
>>>    {
>>> @@ -832,7 +897,7 @@ guc_engine_timedout_job(struct drm_sched_job *drm_job)
>>>    			err = -EIO;
>>>    		set_engine_banned(e);
>>>    		xe_engine_get(e);
>>> -		disable_scheduling_deregister(engine_to_guc(e), e);
>>> +		disable_scheduling_deregister(guc, e);
>>>    		/*
>>>    		 * Must wait for scheduling to be disabled before signalling
>>> @@ -865,7 +930,7 @@ guc_engine_timedout_job(struct drm_sched_job *drm_job)
>>>    	 */
>>>    	list_add(&drm_job->list, &sched->pending_list);
>>>    	drm_sched_run_wq_start(sched);
>>> -	drm_sched_set_timeout(&e->guc->sched, MIN_SCHED_TIMEOUT);
>>> +	xe_guc_engine_trigger_cleanup(e);
>>>    	/* Mark all outstanding jobs as bad, thus completing them */
>>>    	spin_lock(&sched->job_list_lock);
>>> @@ -889,6 +954,8 @@ static void __guc_engine_fini_async(struct work_struct *w)
>>>    	trace_xe_engine_destroy(e);
>>> +	if (xe_engine_is_lr(e))
>>> +		cancel_work_sync(&ge->lr_tdr);
>>>    	if (e->flags & ENGINE_FLAG_PERSISTENT)
>>>    		xe_device_remove_persistent_engines(gt_to_xe(e->gt), e);
>>>    	release_guc_id(guc, e);
>>> @@ -906,7 +973,7 @@ static void guc_engine_fini_async(struct xe_engine *e)
>>>    	bool kernel = e->flags & ENGINE_FLAG_KERNEL;
>>>    	INIT_WORK(&e->guc->fini_async, __guc_engine_fini_async);
>>> -	queue_work(system_unbound_wq, &e->guc->fini_async);
>>> +	queue_work(system_wq, &e->guc->fini_async);
>>>    	/* We must block on kernel engines so slabs are empty on driver unload */
>>>    	if (kernel) {
>>> @@ -1089,12 +1156,16 @@ static int guc_engine_init(struct xe_engine *e)
>>>    	if (err)
>>>    		goto err_free;
>>> +
>> Unrelated whitespace?
>>
>>
>>>    	sched = &ge->sched;
>>>    	err = drm_sched_entity_init(&ge->entity, DRM_SCHED_PRIORITY_NORMAL,
>>>    				    &sched, 1, NULL);
>>>    	if (err)
>>>    		goto err_sched;
>>> +	if (xe_engine_is_lr(e))
>>> +		INIT_WORK(&e->guc->lr_tdr, xe_guc_engine_lr_cleanup);
>>> +
>>>    	mutex_lock(&guc->submission_state.lock);
>>>    	err = alloc_guc_id(guc, e);
>>> @@ -1146,7 +1217,7 @@ static void guc_engine_kill(struct xe_engine *e)
>>>    {
>>>    	trace_xe_engine_kill(e);
>>>    	set_engine_killed(e);
>>> -	drm_sched_set_timeout(&e->guc->sched, MIN_SCHED_TIMEOUT);
>>> +	xe_guc_engine_trigger_cleanup(e);
>>>    }
>>>    static void guc_engine_add_msg(struct xe_engine *e, struct drm_sched_msg *msg,
>>> @@ -1296,6 +1367,9 @@ static void guc_engine_stop(struct xe_guc *guc, struct xe_engine *e)
>>>    	/* Stop scheduling + flush any DRM scheduler operations */
>>>    	drm_sched_run_wq_stop(sched);
>>> +	if (engine_registered(e) && xe_engine_is_lr(e))
>>> +		xe_engine_put(e);
>>> +
>>>    	/* Clean up lost G2H + reset engine state */
>>>    	if (engine_destroyed(e) && engine_registered(e)) {
>>>    		if (engine_banned(e))
>>> @@ -1520,6 +1594,9 @@ int xe_guc_deregister_done_handler(struct xe_guc *guc, u32 *msg, u32 len)
>>>    	trace_xe_engine_deregister_done(e);
>>>    	clear_engine_registered(e);
>>> +	if (xe_engine_is_lr(e))
>>> +		xe_engine_put(e);
>>> +
>>>    	if (engine_banned(e))
>>>    		xe_engine_put(e);
>>>    	else
>>> @@ -1557,7 +1634,7 @@ int xe_guc_engine_reset_handler(struct xe_guc *guc, u32 *msg, u32 len)
>>>    	 */
>>>    	set_engine_reset(e);
>>>    	if (!engine_banned(e))
>>> -		drm_sched_set_timeout(&e->guc->sched, MIN_SCHED_TIMEOUT);
>>> +		xe_guc_engine_trigger_cleanup(e);
>>>    	return 0;
>>>    }
>>> @@ -1584,7 +1661,7 @@ int xe_guc_engine_memory_cat_error_handler(struct xe_guc *guc, u32 *msg,
>>>    	/* Treat the same as engine reset */
>>>    	set_engine_reset(e);
>>>    	if (!engine_banned(e))
>>> -		drm_sched_set_timeout(&e->guc->sched, MIN_SCHED_TIMEOUT);
>>> +		xe_guc_engine_trigger_cleanup(e);
>>>    	return 0;
>>>    }
>>> diff --git a/drivers/gpu/drm/xe/xe_trace.h b/drivers/gpu/drm/xe/xe_trace.h
>>> index 2f8eb7ebe9a7..02861c26e145 100644
>>> --- a/drivers/gpu/drm/xe/xe_trace.h
>>> +++ b/drivers/gpu/drm/xe/xe_trace.h
>>> @@ -219,6 +219,11 @@ DEFINE_EVENT(xe_engine, xe_engine_resubmit,
>>>    	     TP_ARGS(e)
>>>    );
>>> +DEFINE_EVENT(xe_engine, xe_engine_lr_cleanup,
>>> +	     TP_PROTO(struct xe_engine *e),
>>> +	     TP_ARGS(e)
>>> +);
>>> +
>>>    DECLARE_EVENT_CLASS(xe_sched_job,
>>>    		    TP_PROTO(struct xe_sched_job *job),
>>>    		    TP_ARGS(job),