[PATCH v2] drm/v3d: Add DRM_IOCTL_V3D_PERFMON_SET_GLOBAL

Maíra Canal mcanal at igalia.com
Sun Nov 3 21:01:38 UTC 2024


Hi Christian,

On 31/10/24 17:51, Christian Gmeiner wrote:
> From: Christian Gmeiner <cgmeiner at igalia.com>
> 
> Add a new ioctl, DRM_IOCTL_V3D_PERFMON_SET_GLOBAL, to allow
> configuration of a global performance monitor (perfmon).
> Use the global perfmon for all jobs to ensure consistent
> performance tracking across submissions.
> 
> Signed-off-by: Christian Gmeiner <cgmeiner at igalia.com>
> 
> ---
> Changes in v2:
> - Reworked commit message.
> - Removed num_perfmon counter for tracking perfmon allocations.
> - Allowing allocation of perfmons when the global perfmon is active.
> - Return -EAGAIN for submissions with a per job perfmon if the global perfmon is active.
> ---
>   drivers/gpu/drm/v3d/v3d_drv.c     |  1 +
>   drivers/gpu/drm/v3d/v3d_drv.h     |  8 ++++++++
>   drivers/gpu/drm/v3d/v3d_perfmon.c | 34 +++++++++++++++++++++++++++++++
>   drivers/gpu/drm/v3d/v3d_sched.c   | 14 ++++++++++---
>   drivers/gpu/drm/v3d/v3d_submit.c  | 10 +++++++++
>   include/uapi/drm/v3d_drm.h        | 15 ++++++++++++++
>   6 files changed, 79 insertions(+), 3 deletions(-)
> 

[...]

> diff --git a/drivers/gpu/drm/v3d/v3d_perfmon.c b/drivers/gpu/drm/v3d/v3d_perfmon.c
> index 156be13ab2ef..bf42303c292b 100644
> --- a/drivers/gpu/drm/v3d/v3d_perfmon.c
> +++ b/drivers/gpu/drm/v3d/v3d_perfmon.c
> @@ -312,6 +312,9 @@ static int v3d_perfmon_idr_del(int id, void *elem, void *data)
>   	if (perfmon == v3d->active_perfmon)
>   		v3d_perfmon_stop(v3d, perfmon, false);
>   
> +	/* If the global perfmon is being destroyed, set it to NULL */
> +	cmpxchg(&v3d->global_perfmon, perfmon, NULL);
> +
>   	v3d_perfmon_put(perfmon);
>   
>   	return 0;
> @@ -451,3 +454,34 @@ int v3d_perfmon_get_counter_ioctl(struct drm_device *dev, void *data,
>   
>   	return 0;
>   }
> +
> +int v3d_perfmon_set_global_ioctl(struct drm_device *dev, void *data,
> +				 struct drm_file *file_priv)
> +{
> +	struct v3d_file_priv *v3d_priv = file_priv->driver_priv;
> +	struct drm_v3d_perfmon_set_global *req = data;
> +	struct v3d_dev *v3d = to_v3d_dev(dev);
> +	struct v3d_perfmon *perfmon;
> +
> +	if (req->flags & ~DRM_V3D_PERFMON_CLEAR_GLOBAL)
> +		return -EINVAL;
> +
> +	perfmon = v3d_perfmon_find(v3d_priv, req->id);
> +	if (!perfmon)
> +		return -EINVAL;
> +
> +	/* If the request is to clear the global performance monitor */
> +	if (req->flags & DRM_V3D_PERFMON_CLEAR_GLOBAL) {
> +		if (!v3d->global_perfmon)
> +			return -EINVAL;
> +
> +		xchg(&v3d->global_perfmon, NULL);

I'm reading the userspace code now and I think you need to call
`v3d_perfmon_stop` here to make sure that the active perfmon is no
longer the global perfmon.

Best Regards,
- Maíra

> +
> +		return 0;
> +	}
> +
> +	if (cmpxchg(&v3d->global_perfmon, NULL, perfmon))
> +		return -EBUSY;
> +
> +	return 0;
> +}
> diff --git a/drivers/gpu/drm/v3d/v3d_sched.c b/drivers/gpu/drm/v3d/v3d_sched.c
> index 08d2a2739582..38690740f593 100644
> --- a/drivers/gpu/drm/v3d/v3d_sched.c
> +++ b/drivers/gpu/drm/v3d/v3d_sched.c
> @@ -120,11 +120,19 @@ v3d_cpu_job_free(struct drm_sched_job *sched_job)
>   static void
>   v3d_switch_perfmon(struct v3d_dev *v3d, struct v3d_job *job)
>   {
> -	if (job->perfmon != v3d->active_perfmon)
> +	struct v3d_perfmon *perfmon = v3d->global_perfmon;
> +
> +	if (!perfmon)
> +		perfmon = job->perfmon;
> +
> +	if (perfmon == v3d->active_perfmon)
> +		return;
> +
> +	if (perfmon != v3d->active_perfmon)
>   		v3d_perfmon_stop(v3d, v3d->active_perfmon, true);
>   
> -	if (job->perfmon && v3d->active_perfmon != job->perfmon)
> -		v3d_perfmon_start(v3d, job->perfmon);
> +	if (perfmon && v3d->active_perfmon != perfmon)
> +		v3d_perfmon_start(v3d, perfmon);
>   }
>   
>   static void
> diff --git a/drivers/gpu/drm/v3d/v3d_submit.c b/drivers/gpu/drm/v3d/v3d_submit.c
> index d607aa9c4ec2..9e439c9f0a93 100644
> --- a/drivers/gpu/drm/v3d/v3d_submit.c
> +++ b/drivers/gpu/drm/v3d/v3d_submit.c
> @@ -981,6 +981,11 @@ v3d_submit_cl_ioctl(struct drm_device *dev, void *data,
>   		goto fail;
>   
>   	if (args->perfmon_id) {
> +		if (v3d->global_perfmon) {
> +			ret = -EAGAIN;
> +			goto fail_perfmon;
> +		}
> +
>   		render->base.perfmon = v3d_perfmon_find(v3d_priv,
>   							args->perfmon_id);
>   
> @@ -1196,6 +1201,11 @@ v3d_submit_csd_ioctl(struct drm_device *dev, void *data,
>   		goto fail;
>   
>   	if (args->perfmon_id) {
> +		if (v3d->global_perfmon) {
> +			ret = -EAGAIN;
> +			goto fail_perfmon;
> +		}
> +
>   		job->base.perfmon = v3d_perfmon_find(v3d_priv,
>   						     args->perfmon_id);
>   		if (!job->base.perfmon) {
> diff --git a/include/uapi/drm/v3d_drm.h b/include/uapi/drm/v3d_drm.h
> index 87fc5bb0a61e..709724fe28e6 100644
> --- a/include/uapi/drm/v3d_drm.h
> +++ b/include/uapi/drm/v3d_drm.h
> @@ -43,6 +43,7 @@ extern "C" {
>   #define DRM_V3D_PERFMON_GET_VALUES                0x0a
>   #define DRM_V3D_SUBMIT_CPU                        0x0b
>   #define DRM_V3D_PERFMON_GET_COUNTER               0x0c
> +#define DRM_V3D_PERFMON_SET_GLOBAL                0x0d
>   
>   #define DRM_IOCTL_V3D_SUBMIT_CL           DRM_IOWR(DRM_COMMAND_BASE + DRM_V3D_SUBMIT_CL, struct drm_v3d_submit_cl)
>   #define DRM_IOCTL_V3D_WAIT_BO             DRM_IOWR(DRM_COMMAND_BASE + DRM_V3D_WAIT_BO, struct drm_v3d_wait_bo)
> @@ -61,6 +62,8 @@ extern "C" {
>   #define DRM_IOCTL_V3D_SUBMIT_CPU          DRM_IOW(DRM_COMMAND_BASE + DRM_V3D_SUBMIT_CPU, struct drm_v3d_submit_cpu)
>   #define DRM_IOCTL_V3D_PERFMON_GET_COUNTER DRM_IOWR(DRM_COMMAND_BASE + DRM_V3D_PERFMON_GET_COUNTER, \
>   						   struct drm_v3d_perfmon_get_counter)
> +#define DRM_IOCTL_V3D_PERFMON_SET_GLOBAL  DRM_IOW(DRM_COMMAND_BASE + DRM_V3D_PERFMON_SET_GLOBAL, \
> +						   struct drm_v3d_perfmon_set_global)
>   
>   #define DRM_V3D_SUBMIT_CL_FLUSH_CACHE             0x01
>   #define DRM_V3D_SUBMIT_EXTENSION		  0x02
> @@ -765,6 +768,18 @@ struct drm_v3d_perfmon_get_counter {
>   	__u8 reserved[7];
>   };
>   
> +#define DRM_V3D_PERFMON_CLEAR_GLOBAL    0x0001
> +
> +/*
> + * struct drm_v3d_perfmon_set_global - ioctl to define a
> + * global performance counter that is used if a job has
> + * not assigned one on its own.
> + */
> +struct drm_v3d_perfmon_set_global {
> +	__u32 flags;
> +	__u32 id;
> +};
> +
>   #if defined(__cplusplus)
>   }
>   #endif



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