[Intel-gfx] [PATCH v8 6/6] drm/i915: expose rcs topology through query uAPI

Lionel Landwerlin lionel.g.landwerlin at intel.com
Thu Jan 18 15:17:35 UTC 2018


On 18/01/18 12:46, Tvrtko Ursulin wrote:
>
> On 17/01/2018 15:39, 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)
>>
>> v4: factorize query item writting (Tvrtko)
>>      tweak uapi struct/define names (Tvrtko)
>>
>> v5: Replace ALIGN() macro (Chris)
>>
>> v6: Updated uapi comments (Tvrtko)
>>      Moved flags != 0 checks into vfuncs (Tvrtko)
>>
>> Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
>> ---
>>   drivers/gpu/drm/i915/i915_query.c | 105 
>> ++++++++++++++++++++++++++++++++++++++
>>   include/uapi/drm/i915_drm.h       |  68 ++++++++++++++++++++++++
>>   2 files changed, 173 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_query.c 
>> b/drivers/gpu/drm/i915/i915_query.c
>> index 5aa886313cf9..5d1386db8e7b 100644
>> --- a/drivers/gpu/drm/i915/i915_query.c
>> +++ b/drivers/gpu/drm/i915/i915_query.c
>> @@ -25,8 +25,113 @@
>>   #include "i915_drv.h"
>>   #include <uapi/drm/i915_drm.h>
>>   +static int copy_query_data(struct drm_i915_query_item *query_item,
>> +               const void *item_ptr, u32 item_length,
>> +               const void *data_ptr, u32 data_length)
>> +{
>> +    u32 total_length = item_length + data_length;
>> +
>> +    BUG_ON(add_overflows(item_length, data_length));
>
> Please change to if (WARN_ON_ONCE(...)) return -EINVAL;. Or even 
> GEM_WARN_ON. This can only happen during development so is enough.

Thanks, done.

>
>> +
>> +    if (query_item->length == 0)
>> +        return total_length;
>> +
>> +    if (query_item->length < total_length)
>> +        return -EINVAL;
>
> Did we talk about whether this check should be != or < yet? != would 
> sound safer to me, or you want to allow extending the queries in the 
> future and keeping the same id?

Like Chris said :)

>
>> +
>> +    if (copy_to_user(u64_to_user_ptr(query_item->data_ptr),
>> +             item_ptr, item_length))
>> +        return -EFAULT;
>> +
>> +    if (copy_to_user(u64_to_user_ptr(query_item->data_ptr + 
>> item_length),
>> +             data_ptr, data_length))
>> +        return -EFAULT;
>> +
>> +    return total_length;
>> +}
>> +
>> +static int query_slice_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_slice_info slice_info;
>> +
>> +    if (query_item->flags != 0)
>> +        return -EINVAL;
>> +
>> +    if (sseu->max_slices == 0)
>> +        return -ENODEV;
>> +
>> +    /*
>> +     * 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));
>> +
>> +    memset(&slice_info, 0, sizeof(slice_info));
>> +    slice_info.max_slices = sseu->max_slices;
>> +
>> +    return copy_query_data(query_item, &slice_info, sizeof(slice_info),
>> +                   &sseu->slice_mask, sizeof(sseu->slice_mask));
>> +}
>> +
>> +static int query_subslice_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_subslice_info subslice_info;
>> +    u32 data_length;
>> +
>> +    if (query_item->flags != 0)
>> +        return -EINVAL;
>> +
>> +    if (sseu->max_slices == 0)
>> +        return -ENODEV;
>> +
>> +    memset(&subslice_info, 0, sizeof(subslice_info));
>> +    subslice_info.max_slices = sseu->max_slices;
>> +    subslice_info.max_subslices = sseu->max_subslices;
>> +
>> +    data_length = subslice_info.max_slices *
>> +        DIV_ROUND_UP(subslice_info.max_subslices,
>> +                 sizeof(sseu->subslice_mask[0]) * BITS_PER_BYTE);
>> +
>> +    return copy_query_data(query_item,
>> +                   &subslice_info, sizeof(subslice_info),
>> +                   sseu->subslice_mask, data_length);
>> +}
>> +
>> +static int query_eu_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_eu_info eu_info;
>> +    u32 data_length;
>> +
>> +    if (query_item->flags != 0)
>> +        return -EINVAL;
>> +
>> +    if (sseu->max_slices == 0)
>> +        return -ENODEV;
>> +
>> +    memset(&eu_info, 0, sizeof(eu_info));
>> +    eu_info.max_slices = sseu->max_slices;
>> +    eu_info.max_subslices = sseu->max_subslices;
>> +    eu_info.max_eus_per_subslice = sseu->max_eus_per_subslice;
>> +
>> +    data_length = eu_info.max_slices * eu_info.max_subslices *
>> +        DIV_ROUND_UP(eu_info.max_eus_per_subslice, BITS_PER_BYTE);
>> +
>> +    return copy_query_data(query_item,
>> +                   &eu_info, sizeof(eu_info),
>> +                   sseu->eu_mask, data_length);
>> +}
>> +
>>   static int (* const i915_query_funcs[])(struct drm_i915_private 
>> *dev_priv,
>>                       struct drm_i915_query_item *query_item) = {
>> +    query_slice_info,
>> +    query_subslice_info,
>> +    query_eu_info,
>>   };
>>     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 d94a00380bf6..bcbdd8deb841 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_SLICE_INFO    0x01
>> +#define DRM_I915_QUERY_SUBSLICE_INFO    0x02
>> +#define DRM_I915_QUERY_EU_INFO        0x03
>>         /*
>>        * When set to zero by userspace, this is filled with the size 
>> of the
>> @@ -1650,6 +1653,71 @@ struct drm_i915_query {
>>       __u64 items_ptr;
>>   };
>>   +#define DRM_I915_BIT(bit) ((__u32)1 << (bit))
>> +#define DRM_I915_DIV_ROUND_UP(val, div) (((val) + (div) - 1) / (div))
>> +
>> +/* Data written by the kernel with query DRM_I915_QUERY_SLICE_INFO :
>> + *
>> + * data: each bit indicates whether a slice is available (1) or 
>> fused off (0).
>> + *       Formula to tell if slice X is available :
>> + *
>> + *            (data[X / 8] >> (X % 8)) & 1
>> + *
>> + *       Alternatively, use DRM_I915_QUERY_SLICE_AVAILABLE() to query a
>> + *       given subslice's availability.
>> + */
>> +struct drm_i915_query_slice_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_SUBSLICE_INFO :
>> + *
>> + * data: each bit indicates whether a subslice is available (1) or 
>> fused off
>> + *       (0). Formula to tell if slice X subslice Y is available :
>> + *
>> + *            (data[(X * max_subslices) + Y / 8] >> (Y % 8)) & 1
>> + *
>> + *       Alternatively, use DRM_I915_QUERY_SUBSLICE_AVAILABLE() to 
>> query a
>> + *       given subslice's availability.
>> + */
>> +struct drm_i915_query_subslice_info {
>> +    __u32 max_slices;
>> +    __u32 max_subslices;
>> +
>> +#define DRM_I915_QUERY_SUBSLICE_AVAILABLE(info, slice, subslice) \
>> +    !!((info)->data[(slice) * 
>> DRM_I915_DIV_ROUND_UP((info)->max_subslices, 8) + \
>> +            (subslice) / 8] & DRM_I915_BIT((subslice) % 8))
>> +    __u8 data[];
>> +};
>> +
>> +/* Data written by the kernel with query DRM_I915_QUERY_EU_INFO :
>> + *
>> + * data: Each bit indicates whether an EU is available (1) or fused 
>> off (0).
>> + *       Formula to tell if slice X subslice Y eu Z is available :
>> + *
>> + *           (data[X * max_subslices * ALIGN(max_eus_per_subslice, 
>> 8) / 8 +
>> + *                 Y * ALIGN(max_eus_per_subslice, 8) / 8 +
>> + *                 Z / 8] >> (Z % 8)) & 1
>> + *
>> + *       Alternatively, use DRM_I915_QUERY_EU_AVAILABLE() to query a 
>> given
>> + *       EU's availability.
>> + */
>> +struct drm_i915_query_eu_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) * 
>> DRM_I915_DIV_ROUND_UP((info)->max_eus_per_subslice, 8) * 
>> (info)->max_subslices + \
>> +            (subslice) * 
>> DRM_I915_DIV_ROUND_UP((info)->max_eus_per_subslice, 8) + \
>> +            (eu) / 8] & DRM_I915_BIT((eu) % 8))
>> +    __u8 data[];
>> +};
>> +
>>   #if defined(__cplusplus)
>>   }
>>   #endif
>>
>
> Rest looks OK to me.
>
> Regards,
>
> Tvrtko
>



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