Re: [PATCH] drm/v3d: Add DRM_IOCTL_V3D_PERFMON_SET_GLOBAL

From: Christian Gmeiner
Date: Thu Oct 31 2024 - 17:00:08 EST

Hi André

>
> Em 20/10/2024 17:41, Christian Gmeiner escreveu:
> > From: Christian Gmeiner <cgmeiner@xxxxxxxxxx>
> >
> > This patch adds a new ioctl, DRM_IOCTL_V3D_PERFMON_SET_GLOBAL, which
> > allows the configuration of a global performance monitor (perfmon).
> > The global perfmon is used for all jobs, ensuring consistent performance
> > tracking across submissions.
>
> Usually we write in the imperative form:
>
> Add a new ioctl, ...
>

I switched to imperative from v2.

> >
> > Signed-off-by: Christian Gmeiner <cgmeiner@xxxxxxxxxx>
> > ---
> > drivers/gpu/drm/v3d/v3d_drv.c | 3 ++
> > drivers/gpu/drm/v3d/v3d_drv.h | 10 ++++
> > drivers/gpu/drm/v3d/v3d_perfmon.c | 49 +++++++++++++++++++
> > .../gpu/drm/v3d/v3d_performance_counters.h | 6 +++
> > drivers/gpu/drm/v3d/v3d_sched.c | 10 +++-
> > include/uapi/drm/v3d_drm.h | 15 ++++++
> > 6 files changed, 91 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/v3d/v3d_drv.c b/drivers/gpu/drm/v3d/v3d_drv.c
> > index d7ff1f5fa481..f1753ee2af25 100644
> > --- a/drivers/gpu/drm/v3d/v3d_drv.c
> > +++ b/drivers/gpu/drm/v3d/v3d_drv.c
> > @@ -214,6 +214,7 @@ static const struct drm_ioctl_desc v3d_drm_ioctls[] = {
> > DRM_IOCTL_DEF_DRV(V3D_PERFMON_GET_VALUES, v3d_perfmon_get_values_ioctl, DRM_RENDER_ALLOW),
> > DRM_IOCTL_DEF_DRV(V3D_SUBMIT_CPU, v3d_submit_cpu_ioctl, DRM_RENDER_ALLOW | DRM_AUTH),
> > DRM_IOCTL_DEF_DRV(V3D_PERFMON_GET_COUNTER, v3d_perfmon_get_counter_ioctl, DRM_RENDER_ALLOW),
> > + DRM_IOCTL_DEF_DRV(V3D_PERFMON_SET_GLOBAL, v3d_perfmon_set_global_ioctl, DRM_RENDER_ALLOW),
> > };
> >
> > static const struct drm_driver v3d_drm_driver = {
> > @@ -350,6 +351,8 @@ static int v3d_platform_drm_probe(struct platform_device *pdev)
> > if (ret)
> > goto drm_unregister;
> >
> > + atomic_set(&v3d->num_perfmon, 0);
> > +
> > return 0;
> >
> > drm_unregister:
> > diff --git a/drivers/gpu/drm/v3d/v3d_drv.h b/drivers/gpu/drm/v3d/v3d_drv.h
> > index cf4b23369dc4..9491d730d99f 100644
> > --- a/drivers/gpu/drm/v3d/v3d_drv.h
> > +++ b/drivers/gpu/drm/v3d/v3d_drv.h
> > @@ -61,6 +61,8 @@ struct v3d_queue_state {
> > struct v3d_stats stats;
> > };
> >
> > +struct v3d_dev;
> > +
>
> Forward declarations go in the beginning of the file, along with the
> other ones:
>
> struct clk;
> struct platform_device;
> struct reset_control;
> +struct v3d_dev;
>

I am happy that I do not need this in v2 anymore.

> > /* Performance monitor object. The perform lifetime is controlled by userspace
> > * using perfmon related ioctls. A perfmon can be attached to a submit_cl
> > * request, and when this is the case, HW perf counters will be activated just
> > @@ -68,6 +70,9 @@ struct v3d_queue_state {
> > * done. This way, only events related to a specific job will be counted.
> > */
> > struct v3d_perfmon {
> > + /* Pointer back to v3d instance this perfmon belongs. */
> > + struct v3d_dev *v3d;
> > +
> > /* Tracks the number of users of the perfmon, when this counter reaches
> > * zero the perfmon is destroyed.
> > */
> > @@ -179,6 +184,9 @@ struct v3d_dev {
> > u32 num_allocated;
> > u32 pages_allocated;
> > } bo_stats;
> > +
> > + /* Keep track of current number of allocated perfmons. */
> > + atomic_t num_perfmon;
> > };
> >
> > static inline struct v3d_dev *
> > @@ -584,6 +592,8 @@ int v3d_perfmon_get_values_ioctl(struct drm_device *dev, void *data,
> > struct drm_file *file_priv);
> > int v3d_perfmon_get_counter_ioctl(struct drm_device *dev, void *data,
> > struct drm_file *file_priv);
> > +int v3d_perfmon_set_global_ioctl(struct drm_device *dev, void *data,
> > + struct drm_file *file_priv);
> >
> > /* v3d_sysfs.c */
> > int v3d_sysfs_init(struct device *dev);
>
> [...]
>
> > diff --git a/include/uapi/drm/v3d_drm.h b/include/uapi/drm/v3d_drm.h
> > index 87fc5bb0a61e..960d392d75a3 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];
> > };
> >
> > +/**
>
> Using /** means that you are writting a kernel-doc comment [1], so make
> sure to describe each struct member, otherwise it's going to generate
> build warnings with W=1.
>

Learned something new - thanks for sharing.

> > + * 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.
> > + */
> > +
> > +#define DRM_V3D_PERFMON_CLEAR_GLOBAL 0x0001
>
> I would keep this define above the struct comment.
>

Sure .. have done it in v2 of the patch.

> > +struct drm_v3d_perfmon_set_global {
> > + __u32 flags;
> > + __u32 id;
> > +};
> > +
> > #if defined(__cplusplus)
> > }
> > #endif
>
> [1] https://www.kernel.org/doc/html/latest/doc-guide/kernel-doc.html
>

--
greets
--
Christian Gmeiner, MSc

https://christian-gmeiner.info/privacypolicy