[Intel-gfx] [PATCH] drm/i915/uapi: Add DRM_I915_QUERY_GEOMETRY_SUBSLICES

Matt Roper matthew.d.roper at intel.com
Mon Mar 28 16:01:29 UTC 2022


On Mon, Mar 28, 2022 at 09:44:36AM +0100, Tvrtko Ursulin wrote:
> 
> + Joonas
> 
> On 25/03/2022 23:03, Francisco Jerez wrote:
> > Matt Atwood <matthew.s.atwood at intel.com> writes:
> > 
> > > Newer platforms have DSS that aren't necessarily available for both
> > > geometry and compute, two queries will need to exist. This introduces
> > > the first, when passing a valid engine class and engine instance in the
> > > flags returns a topology describing geometry.
> > > 
> > > v2: fix white space errors
> > > v3: change flags from hosting 2 8 bit numbers to holding a
> > > i915_engine_class_instance struct
> > > 
> > > Cc: Ashutosh Dixit <ashutosh.dixit at intel.com>
> > > Cc: Matt Roper <matthew.d.roper at intel.com>
> > > Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> > > UMD (mesa): https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14143
> > > Signed-off-by: Matt Atwood <matthew.s.atwood at intel.com>
> > > ---
> > >   drivers/gpu/drm/i915/i915_query.c | 68 ++++++++++++++++++++++---------
> > >   include/uapi/drm/i915_drm.h       | 24 +++++++----
> > >   2 files changed, 65 insertions(+), 27 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/i915_query.c b/drivers/gpu/drm/i915/i915_query.c
> > > index 2dfbc22857a3..fcb374201edb 100644
> > > --- a/drivers/gpu/drm/i915/i915_query.c
> > > +++ b/drivers/gpu/drm/i915/i915_query.c
> > > @@ -9,6 +9,7 @@
> > >   #include "i915_drv.h"
> > >   #include "i915_perf.h"
> > >   #include "i915_query.h"
> > > +#include "gt/intel_engine_user.h"
> > >   #include <uapi/drm/i915_drm.h>
> > >   static int copy_query_item(void *query_hdr, size_t query_sz,
> > > @@ -28,36 +29,30 @@ static int copy_query_item(void *query_hdr, size_t query_sz,
> > >   	return 0;
> > >   }
> > > -static int query_topology_info(struct drm_i915_private *dev_priv,
> > > -			       struct drm_i915_query_item *query_item)
> > > +static int fill_topology_info(const struct sseu_dev_info *sseu,
> > > +			      struct drm_i915_query_item *query_item,
> > > +			      const u8 *subslice_mask)
> > >   {
> > > -	const struct sseu_dev_info *sseu = &to_gt(dev_priv)->info.sseu;
> > >   	struct drm_i915_query_topology_info topo;
> > >   	u32 slice_length, subslice_length, eu_length, total_length;
> > >   	int ret;
> > > -	if (query_item->flags != 0)
> > > -		return -EINVAL;
> > > +	BUILD_BUG_ON(sizeof(u8) != sizeof(sseu->slice_mask));
> > >   	if (sseu->max_slices == 0)
> > >   		return -ENODEV;
> > > -	BUILD_BUG_ON(sizeof(u8) != sizeof(sseu->slice_mask));
> > > -
> > >   	slice_length = sizeof(sseu->slice_mask);
> > >   	subslice_length = sseu->max_slices * sseu->ss_stride;
> > >   	eu_length = sseu->max_slices * sseu->max_subslices * sseu->eu_stride;
> > >   	total_length = sizeof(topo) + slice_length + subslice_length +
> > >   		       eu_length;
> > > -	ret = copy_query_item(&topo, sizeof(topo), total_length,
> > > -			      query_item);
> > > +	ret = copy_query_item(&topo, sizeof(topo), total_length, query_item);
> > > +
> > >   	if (ret != 0)
> > >   		return ret;
> > > -	if (topo.flags != 0)
> > > -		return -EINVAL;
> > > -
> > >   	memset(&topo, 0, sizeof(topo));
> > >   	topo.max_slices = sseu->max_slices;
> > >   	topo.max_subslices = sseu->max_subslices;
> > > @@ -69,27 +64,61 @@ static int query_topology_info(struct drm_i915_private *dev_priv,
> > >   	topo.eu_stride = sseu->eu_stride;
> > >   	if (copy_to_user(u64_to_user_ptr(query_item->data_ptr),
> > > -			   &topo, sizeof(topo)))
> > > +			 &topo, sizeof(topo)))
> > >   		return -EFAULT;
> > >   	if (copy_to_user(u64_to_user_ptr(query_item->data_ptr + sizeof(topo)),
> > > -			   &sseu->slice_mask, slice_length))
> > > +			 &sseu->slice_mask, slice_length))
> > >   		return -EFAULT;
> > >   	if (copy_to_user(u64_to_user_ptr(query_item->data_ptr +
> > > -					   sizeof(topo) + slice_length),
> > > -			   sseu->subslice_mask, subslice_length))
> > > +					 sizeof(topo) + slice_length),
> > > +			 subslice_mask, subslice_length))
> > >   		return -EFAULT;
> > >   	if (copy_to_user(u64_to_user_ptr(query_item->data_ptr +
> > > -					   sizeof(topo) +
> > > -					   slice_length + subslice_length),
> > > -			   sseu->eu_mask, eu_length))
> > > +					 sizeof(topo) +
> > > +					 slice_length + subslice_length),
> > > +			 sseu->eu_mask, eu_length))
> > >   		return -EFAULT;
> > >   	return total_length;
> > >   }
> > > +static int query_topology_info(struct drm_i915_private *dev_priv,
> > > +			       struct drm_i915_query_item *query_item)
> > > +{
> > > +	const struct sseu_dev_info *sseu = &to_gt(dev_priv)->info.sseu;
> > > +
> > > +	if (query_item->flags != 0)
> > > +		return -EINVAL;
> > > +
> > > +	return fill_topology_info(sseu, query_item, sseu->subslice_mask);
> > > +}
> > > +
> > > +static int query_geometry_subslices(struct drm_i915_private *i915,
> > > +				    struct drm_i915_query_item *query_item)
> > > +{
> > > +	const struct sseu_dev_info *sseu;
> > > +	struct intel_engine_cs *engine;
> > > +	struct i915_engine_class_instance classinstance;
> > > +
> > > +	if (GRAPHICS_VER_FULL(i915) < IP_VER(12, 50))
> > > +		return -ENODEV;
> > > +
> > > +	classinstance = *((struct i915_engine_class_instance *)&query_item->flags);
> > > +
> > > +	engine = intel_engine_lookup_user(i915, (u8) classinstance.engine_class,
> > > +					  (u8) classinstance.engine_instance);
> > > +
> > > +	if (!engine)
> > > +		return -EINVAL;
> > > +
> > > +	sseu = &engine->gt->info.sseu;
> > > +
> > > +	return fill_topology_info(sseu, query_item, sseu->geometry_subslice_mask);
> > > +}
> > > +
> > >   static int
> > >   query_engine_info(struct drm_i915_private *i915,
> > >   		  struct drm_i915_query_item *query_item)
> > > @@ -485,6 +514,7 @@ static int (* const i915_query_funcs[])(struct drm_i915_private *dev_priv,
> > >   	query_engine_info,
> > >   	query_perf_config,
> > >   	query_memregion_info,
> > > +	query_geometry_subslices,
> > >   };
> > >   int i915_query_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
> > > diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> > > index 05c3642aaece..b539c83a4034 100644
> > > --- a/include/uapi/drm/i915_drm.h
> > > +++ b/include/uapi/drm/i915_drm.h
> > > @@ -2687,10 +2687,11 @@ struct drm_i915_perf_oa_config {
> > >   struct drm_i915_query_item {
> > >   	/** @query_id: The id for this query */
> > >   	__u64 query_id;
> > > -#define DRM_I915_QUERY_TOPOLOGY_INFO    1
> > > -#define DRM_I915_QUERY_ENGINE_INFO	2
> > > -#define DRM_I915_QUERY_PERF_CONFIG      3
> > > -#define DRM_I915_QUERY_MEMORY_REGIONS   4
> > > +#define DRM_I915_QUERY_TOPOLOGY_INFO		1
> > > +#define DRM_I915_QUERY_ENGINE_INFO		2
> > > +#define DRM_I915_QUERY_PERF_CONFIG		3
> > > +#define DRM_I915_QUERY_MEMORY_REGIONS		4
> > > +#define DRM_I915_QUERY_GEOMETRY_SUBSLICES	5
> > >   /* Must be kept compact -- no holes and well documented */
> > >   	/**
> > > @@ -2714,6 +2715,9 @@ struct drm_i915_query_item {
> > >   	 *	- DRM_I915_QUERY_PERF_CONFIG_LIST
> > >   	 *      - DRM_I915_QUERY_PERF_CONFIG_DATA_FOR_UUID
> > >   	 *      - DRM_I915_QUERY_PERF_CONFIG_FOR_UUID
> > > +	 *
> > > +	 * When query_id == DRM_I915_QUERY_GEOMETRY_SUBSLICES must have a valid
> > > +	 * i915_engine_class_instance struct.
> > 
> > To get back to our previous discussion off-list, I find this interface
> > kind of confusing, since it's expecting an engine ID as argument, but it
> > returns the set of subslices available to the *render* engine regardless
> > of the engine class specified.  I think it would make sense to rename
> > this to DRM_I915_QUERY_ENGINE_SUBSLICES or similar and have the mask
> > returned be the set of subslices actually available to the engine that
> > was specified (e.g. the compute subslice mask if a compute engine is
> > specified, or an error if the engine specified doesn't have any
> > connection to subslices).  Alternatively, if this is really only meant
> > to work for the render engine, maybe the engine class should be dropped
> > from "flags", only the engine instance is necessary -- I think that
> > would prevent programming errors and would leave additional room in
> > "flags" for future expansion.
> 
> I have asked a similar question and AFAIR Matt explained it was an arch
> level direction to have it like it is. Not sure of the reasoning.
> 
> I wouldn't take the option of implying render and only having instance in
> flags, but returning error for engines not applicable sounds good to me. If
> there isn't a good reason not to do it.

GEOMETRY_SUBSLICES doesn't really have any meaning for non-RCS engines,
so returning an error if the query is performed against a media,
blitter, or compute engine is probably fine.

MattA also has a COMPUTE_SUBSLICES query coming as well, and I believe
the compute subslices query would be relevant to both render and compute
engines since gpgpu workloads can be submitted to either.  So keeping
the engine type (and maintaining a consistent signature for the two
queries) is probably the way to go.


Matt

> 
> Regards,
> 
> Tvrtko

-- 
Matt Roper
Graphics Software Engineer
VTT-OSGC Platform Enablement
Intel Corporation
(916) 356-2795


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