[Intel-gfx] [PATCH v4 6/6] drm/i915: expose rcs topology through query uAPI
Tvrtko Ursulin
tvrtko.ursulin at linux.intel.com
Mon Jan 15 17:54:57 UTC 2018
On 15/01/2018 14:41, Lionel Landwerlin wrote:
> With the introduction of asymmetric slices in CNL, we cannot rely on
> the previous SUBSLICE_MASK getparam to tell userspace what subslices
> are available. Here we introduce a more detailed way of querying the
> Gen's GPU topology that doesn't aggregate numbers.
>
> This is essential for monitoring parts of the GPU with the OA unit,
> because counters need to be normalized to the number of
> EUs/subslices/slices. The current aggregated numbers like EU_TOTAL do
> not gives us sufficient information.
>
> As a bonus we can draw representations of the GPU :
>
> https://imgur.com/a/vuqpa
>
> v2: Rename uapi struct s/_mask/_info/ (Tvrtko)
> Report max_slice/subslice/eus_per_subslice rather than strides (Tvrtko)
> Add uapi macros to read data from *_info structs (Tvrtko)
>
> v3: Use !!(v & DRM_I915_BIT()) for uapi macros instead of custom shifts (Tvrtko)
>
> Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
> ---
> drivers/gpu/drm/i915/i915_query.c | 134 ++++++++++++++++++++++++++++++++++++++
> include/uapi/drm/i915_drm.h | 53 +++++++++++++++
> 2 files changed, 187 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_query.c b/drivers/gpu/drm/i915/i915_query.c
> index 5694cfea4553..465ec18a472f 100644
> --- a/drivers/gpu/drm/i915/i915_query.c
> +++ b/drivers/gpu/drm/i915/i915_query.c
> @@ -25,8 +25,129 @@
> #include "i915_drv.h"
> #include <uapi/drm/i915_drm.h>
>
> +static int query_slices_info(struct drm_i915_private *dev_priv,
> + struct drm_i915_query_item *query_item)
> +{
> + const struct sseu_dev_info *sseu = &INTEL_INFO(dev_priv)->sseu;
> + struct drm_i915_query_slices_info slices_info;
> + u32 data_length, length;
> +
> + if (sseu->max_slices == 0)
> + return -ENODEV;
> +
> + data_length = sizeof(sseu->slice_mask);
> + length = sizeof(slices_info) + data_length;
> +
> + /*
> + * If we ever change the internal slice mask data type, we'll need to
> + * update this function.
> + */
> + BUILD_BUG_ON(sizeof(u8) != sizeof(sseu->slice_mask));
> +
> + if (query_item->length == 0) {
> + query_item->length = length;
> + return 0;
> + }
> +
> + if (query_item->length != length)
> + return -EINVAL;
> +
> + memset(&slices_info, 0, sizeof(slices_info));
> + slices_info.max_slices = sseu->max_slices;
> +
> + if (copy_to_user(u64_to_user_ptr(query_item->data_ptr), &slices_info,
> + sizeof(slices_info)))
> + return -EFAULT;
> +
> + if (copy_to_user(u64_to_user_ptr(query_item->data_ptr +
> + offsetof(struct drm_i915_query_slices_info, data)),
> + &sseu->slice_mask, data_length))
> + return -EFAULT;
> +
> + return 0;
> +}
> +
> +static int query_subslices_info(struct drm_i915_private *dev_priv,
> + struct drm_i915_query_item *query_item)
> +{
> + const struct sseu_dev_info *sseu = &INTEL_INFO(dev_priv)->sseu;
> + struct drm_i915_query_subslices_info subslices_info;
> + u32 data_length, length;
> +
> + if (sseu->max_slices == 0)
> + return -ENODEV;
> +
> + memset(&subslices_info, 0, sizeof(subslices_info));
> + subslices_info.max_slices = sseu->max_slices;
> + subslices_info.max_subslices = sseu->max_subslices;
> +
> + data_length = subslices_info.max_slices *
> + DIV_ROUND_UP(subslices_info.max_subslices,
> + sizeof(sseu->subslice_mask[0]) * BITS_PER_BYTE);
> + length = sizeof(subslices_info) + data_length;
> +
> + if (query_item->length == 0) {
> + query_item->length = length;
> + return 0;
> + }
> +
> + if (query_item->length != length)
> + return -EINVAL;
> +
> + if (copy_to_user(u64_to_user_ptr(query_item->data_ptr), &subslices_info,
> + sizeof(subslices_info)))
> + return -EFAULT;
> +
> + if (copy_to_user(u64_to_user_ptr(query_item->data_ptr +
> + offsetof(struct drm_i915_query_subslices_info, data)),
> + sseu->subslice_mask, data_length))
> + return -EFAULT;
> +
> + return 0;
> +}
> +
> +static int query_eus_info(struct drm_i915_private *dev_priv,
> + struct drm_i915_query_item *query_item)
> +{
> + const struct sseu_dev_info *sseu = &INTEL_INFO(dev_priv)->sseu;
> + struct drm_i915_query_eus_info eus_info;
> + u32 data_length, length;
> +
> + if (sseu->max_slices == 0)
> + return -ENODEV;
> +
> + memset(&eus_info, 0, sizeof(eus_info));
> + eus_info.max_slices = sseu->max_slices;
> + eus_info.max_subslices = sseu->max_subslices;
> + eus_info.max_eus_per_subslice = sseu->max_eus_per_subslice;
> +
> + data_length = eus_info.max_slices * eus_info.max_subslices *
> + DIV_ROUND_UP(eus_info.max_eus_per_subslice, BITS_PER_BYTE);
> + length = sizeof(eus_info) + data_length;
> +
> + if (query_item->length == 0) {
> + query_item->length = length;
> + return 0;
> + }
> +
> + if (query_item->length != length)
> + return -EINVAL;
> +
> + if (copy_to_user(u64_to_user_ptr(query_item->data_ptr), &eus_info,
> + sizeof(eus_info)))
> + return -EFAULT;
> +
> + if (copy_to_user(u64_to_user_ptr(query_item->data_ptr +
> + offsetof(struct drm_i915_query_eus_info, data)),
> + sseu->eu_mask, data_length))
> + return -EFAULT;
I think in all three queries, once you have the length, you could
extract the four if statement above into a common helper? Arguments are
query_item, length, data_length, ptr_query_item, ptr_data, and
offset_data, unless I am missing something. Up to you if you would find
that a worthy compaction.
> +
> + return 0;
> +}
> +
> int i915_query_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
> {
> + struct drm_i915_private *dev_priv = to_i915(dev);
> struct drm_i915_query *args = data;
> struct drm_i915_query_item __user *user_item_ptr =
> u64_to_user_ptr(args->items_ptr);
> @@ -34,15 +155,28 @@ int i915_query_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
>
> for (i = 0; i < args->num_items; i++, user_item_ptr++) {
> struct drm_i915_query_item item;
> + int ret;
>
> if (copy_from_user(&item, user_item_ptr, sizeof(item)))
> return -EFAULT;
>
> switch (item.query_id) {
> + case DRM_I915_QUERY_ID_SLICES_INFO:
> + ret = query_slices_info(dev_priv, &item);
> + break;
> + case DRM_I915_QUERY_ID_SUBSLICES_INFO:
> + ret = query_subslices_info(dev_priv, &item);
> + break;
> + case DRM_I915_QUERY_ID_EUS_INFO:
> + ret = query_eus_info(dev_priv, &item);
> + break;
> default:
> return -EINVAL;
> }
>
> + if (ret)
> + return ret;
> +
> if (copy_to_user(user_item_ptr, &item, sizeof(item)))
> return -EFAULT;
> }
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index 39e93f10f2cd..d25f21e3c107 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -1618,6 +1618,9 @@ struct drm_i915_perf_oa_config {
>
> struct drm_i915_query_item {
> __u64 query_id;
> +#define DRM_I915_QUERY_ID_SLICES_INFO 0x01
> +#define DRM_I915_QUERY_ID_SUBSLICES_INFO 0x02
> +#define DRM_I915_QUERY_ID_EUS_INFO 0x03
Would DRM_I915_QUERY_ID_"singular"_INFO read better? In struct names as
well if so?
>
> /*
> * When set to zero by userspace, this is filled with the size of the
> @@ -1644,6 +1647,56 @@ struct drm_i915_query {
> __u64 items_ptr;
> };
Okay.. up to here it's all pretty much fine.
>
> +#define DRM_I915_BIT(bit) (1 << (bit))
> +
> +/* Data written by the kernel with query DRM_I915_QUERY_ID_SLICES_INFO :
> + *
> + * data: each bit indicates whether a slice is available (1) or fused off (0).
> + * Use DRM_I915_QUERY_SLICE_AVAILABLE() to query a given slice's
> + * availability.
> + */
> +struct drm_i915_query_slices_info {
> + __u32 max_slices;
> +
> +#define DRM_I915_QUERY_SLICE_AVAILABLE(info, slice) \
> + !!((info)->data[(slice) / 8] & DRM_I915_BIT((slice) % 8))
> + __u8 data[];
> +};
> +
> +/* Data written by the kernel with query DRM_I915_QUERY_ID_SUBSLICES_INFO :
> + *
> + * data: each bit indicates whether a subslice is available (1) or fused off
> + * (0). Use DRM_I915_QUERY_SUBSLICE_AVAILABLE() to query a given
> + * subslice's availability.
> + */
> +struct drm_i915_query_subslices_info {
> + __u32 max_slices;
> + __u32 max_subslices;
> +
> +#define DRM_I915_QUERY_SUBSLICE_AVAILABLE(info, slice, subslice) \
> + !!((info)->data[(slice) * ALIGN((info)->max_subslices, 8) / 8 + \
> + (subslice) / 8] & DRM_I915_BIT((subslice) % 8))
> + __u8 data[];
> +};
> +
> +/* Data written by the kernel with query DRM_I915_QUERY_ID_EUS_INFO :
> + *
> + * data: Each bit indicates whether a subslice is available (1) or fused off
> + * (0). Use DRM_I915_QUERY_EU_AVAILABLE() to query a given EU's
> + * availability.
> + */
> +struct drm_i915_query_eus_info {
> + __u32 max_slices;
> + __u32 max_subslices;
> + __u32 max_eus_per_subslice;
> +
> +#define DRM_I915_QUERY_EU_AVAILABLE(info, slice, subslice, eu) \
> + !!((info)->data[(slice) * ALIGN((info)->max_eus_per_subslice, 8) / 8 * (info)->max_subslices + \
> + (subslice) * ALIGN((info)->max_eus_per_subslice, 8) / 8 + \
> + (eu) / 8] & DRM_I915_BIT((eu) % 8))
> + __u8 data[];
> +};
> +
> #if defined(__cplusplus)
> }
> #endif
>
This last bit however I'm a bit unsure of.
I know I suggested the accessor macros but now they look a bit
unsightly. I don't have ideas on how to improve them though.
And the unspecified length array is also potentially questionable.
I'll take the liberty of Cc-ing Chris and Joonas to start with to see if
they have comments on the above.
Regards,
Tvrtko
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