[PATCH 1/3] drm/scheduler: track GPU active time per entity

[Lucas Stach]

Am Donnerstag, dem 08.09.2022 um 14:33 -0400 schrieb Andrey Grodzovsky:
> On 2022-09-08 14:10, Lucas Stach wrote:
> > Track the accumulated time that jobs from this entity were active
> > on the GPU. This allows drivers using the scheduler to trivially
> > implement the DRM fdinfo when the hardware doesn't provide more
> > specific information than signalling job completion anyways.
> > 
> > Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
> > ---
> >   drivers/gpu/drm/scheduler/sched_main.c | 6 ++++++
> >   include/drm/gpu_scheduler.h            | 7 +++++++
> >   2 files changed, 13 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
> > index 76fd2904c7c6..24c77a6a157f 100644
> > --- a/drivers/gpu/drm/scheduler/sched_main.c
> > +++ b/drivers/gpu/drm/scheduler/sched_main.c
> > @@ -847,6 +847,12 @@ drm_sched_get_cleanup_job(struct drm_gpu_scheduler *sched)
> >   
> >   	spin_unlock(&sched->job_list_lock);
> >   
> > +	if (job) {
> > +		job->entity->elapsed_ns += ktime_to_ns(
> > +			ktime_sub(job->s_fence->finished.timestamp,
> > +				  job->s_fence->scheduled.timestamp));
> > +	}
> > +
> >   	return job;
> 
> 
> Looks like you making as assumption that drm_sched_entity will always be 
> allocated using kzalloc ? Isn't it a bit dangerous assumption ?
> 
No, drm_sched_entity_init() memsets the whole struct to 0 before
initializing any members that need more specific init values.

Regards,
Lucas

> Andrey
> 
> 
> >   }
> >   
> > diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
> > index addb135eeea6..573bef640664 100644
> > --- a/include/drm/gpu_scheduler.h
> > +++ b/include/drm/gpu_scheduler.h
> > @@ -196,6 +196,13 @@ struct drm_sched_entity {
> >   	 * drm_sched_entity_fini().
> >   	 */
> >   	struct completion		entity_idle;
> > +	/**
> > +	 * @elapsed_ns
> > +	 *
> > +	 * Records the amount of time where jobs from this entity were active
> > +	 * on the GPU.
> > +	 */
> > +	uint64_t elapsed_ns;
> >   };
> >   
> >   /**