[Mesa-dev] [PATCH v2 56/59] i965/fs: push first double-based uniforms in push constant buffer

Pohjolainen, Topi topi.pohjolainen at intel.com
Mon May 9 05:21:15 UTC 2016


On Fri, May 06, 2016 at 08:56:08AM +0200, Samuel Iglesias Gons?lvez wrote:
> When there is a mix of definitions of uniforms with 32-bit or 64-bit
> data type sizes, the driver ends up doing misaligned access to double
> based variables in the push constant buffer.
> 
> To fix this, this patch pushes first all the 64-bit variables and
> then the rest. Then, all the variables would be aligned to
> its data type size.
> 
> Signed-off-by: Samuel Iglesias Gonsálvez <siglesias at igalia.com>
> ---
>  src/mesa/drivers/dri/i965/brw_fs.cpp | 113 +++++++++++++++++++++++++----------
>  1 file changed, 83 insertions(+), 30 deletions(-)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
> index 65aa3c7..7eaf1b4 100644
> --- a/src/mesa/drivers/dri/i965/brw_fs.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
> @@ -39,6 +39,7 @@
>  #include "brw_program.h"
>  #include "brw_dead_control_flow.h"
>  #include "compiler/glsl_types.h"
> +#include "program/prog_parameter.h"
>  
>  using namespace brw;
>  
> @@ -2004,6 +2005,45 @@ fs_visitor::compact_virtual_grfs()
>     return progress;
>  }
>  
> +static void
> +set_push_pull_constant_loc(unsigned uniform, int &chunk_start, bool contiguous,
> +                           int *push_constant_loc, int *pull_constant_loc,
> +                           unsigned &num_push_constants,
> +                           unsigned &num_pull_constants,

I don't remember us using writable references elsewhere, and vaguely recall
there being a debate about this and decision to use pointers instead?

> +                           const unsigned max_push_components,
> +                           const unsigned max_chunk_size,
> +                           struct brw_stage_prog_data *stage_prog_data)
> +{
> +   /* This is the first live uniform in the chunk */
> +   if (chunk_start < 0)
> +      chunk_start = uniform;
> +
> +   /* If this element does not need to be contiguous with the next, we
> +    * split at this point and everthing between chunk_start and u forms a
                                     ^

                                 everything

> +    * single chunk.
> +    */
> +   if (!contiguous) {
> +      unsigned chunk_size = uniform - chunk_start + 1;
> +
> +      /* Decide whether we should push or pull this parameter.  In the
> +       * Vulkan driver, push constants are explicitly exposed via the API
> +       * so we push everything.  In GL, we only push small arrays.
> +       */
> +      if (stage_prog_data->pull_param == NULL ||
> +          (num_push_constants + chunk_size <= max_push_components &&
> +           chunk_size <= max_chunk_size)) {
> +         assert(num_push_constants + chunk_size <= max_push_components);
> +         for (unsigned j = chunk_start; j <= uniform; j++)
> +            push_constant_loc[j] = num_push_constants++;
> +      } else {
> +         for (unsigned j = chunk_start; j <= uniform; j++)
> +            pull_constant_loc[j] = num_pull_constants++;
> +      }
> +
> +      chunk_start = -1;
> +   }
> +}
> +
>  /**
>   * Assign UNIFORM file registers to either push constants or pull constants.
>   *
> @@ -2022,6 +2062,8 @@ fs_visitor::assign_constant_locations()
>  
>     bool is_live[uniforms];
>     memset(is_live, 0, sizeof(is_live));
> +   bool is_live_64bit[uniforms];
> +   memset(is_live_64bit, 0, sizeof(is_live_64bit));
>  
>     /* For each uniform slot, a value of true indicates that the given slot and
>      * the next slot must remain contiguous.  This is used to keep us from
> @@ -2054,14 +2096,21 @@ fs_visitor::assign_constant_locations()
>              for (unsigned j = constant_nr; j < last; j++) {
>                 is_live[j] = true;
>                 contiguous[j] = true;
> +               if (type_sz(inst->src[i].type) == 8) {
> +                  is_live_64bit[j] = true;
> +               }
>              }
>              is_live[last] = true;
>           } else {
>              if (constant_nr >= 0 && constant_nr < (int) uniforms) {
>                 int regs_read = inst->components_read(i) *
>                    type_sz(inst->src[i].type) / 4;
> -               for (int j = 0; j < regs_read; j++)
> +               for (int j = 0; j < regs_read; j++) {
>                    is_live[constant_nr + j] = true;
> +                  if (type_sz(inst->src[i].type) == 8) {
> +                     is_live_64bit[constant_nr + j] = true;
> +                  }
> +               }
>              }
>           }
>        }
> @@ -2090,43 +2139,46 @@ fs_visitor::assign_constant_locations()
>     pull_constant_loc = ralloc_array(mem_ctx, int, uniforms);
>  
>     int chunk_start = -1;
> +
> +

Extra newline.

> +   /* First push 64-bit uniforms */
>     for (unsigned u = 0; u < uniforms; u++) {
> -      push_constant_loc[u] = -1;
> +      if (!is_live[u] || !is_live_64bit[u])
> +         continue;
> +
>        pull_constant_loc[u] = -1;
> +      push_constant_loc[u] = -1;
>  
> -      if (!is_live[u])
> -         continue;
> +      set_push_pull_constant_loc(u, chunk_start, contiguous[u],
> +                                 push_constant_loc, pull_constant_loc,
> +                                 num_push_constants, num_pull_constants,
> +                                 max_push_components, max_chunk_size,
> +                                 stage_prog_data);
>  
> -      /* This is the first live uniform in the chunk */
> -      if (chunk_start < 0)
> -         chunk_start = u;
> +   }
>  
> -      /* If this element does not need to be contiguous with the next, we
> -       * split at this point and everthing between chunk_start and u forms a
> -       * single chunk.
> -       */
> -      if (!contiguous[u]) {
> -         unsigned chunk_size = u - chunk_start + 1;
> +   /* Then push the rest of uniforms */
> +   for (unsigned u = 0; u < uniforms; u++) {
> +      if (!is_live[u] || is_live_64bit[u])
> +         continue;
>  
> -         /* Decide whether we should push or pull this parameter.  In the
> -          * Vulkan driver, push constants are explicitly exposed via the API
> -          * so we push everything.  In GL, we only push small arrays.
> -          */
> -         if (stage_prog_data->pull_param == NULL ||
> -             (num_push_constants + chunk_size <= max_push_components &&
> -              chunk_size <= max_chunk_size)) {
> -            assert(num_push_constants + chunk_size <= max_push_components);
> -            for (unsigned j = chunk_start; j <= u; j++)
> -               push_constant_loc[j] = num_push_constants++;
> -         } else {
> -            for (unsigned j = chunk_start; j <= u; j++)
> -               pull_constant_loc[j] = num_pull_constants++;
> -         }
> +      pull_constant_loc[u] = -1;
> +      push_constant_loc[u] = -1;
>  
> -         chunk_start = -1;
> -      }
> +      set_push_pull_constant_loc(u, chunk_start, contiguous[u],
> +                                 push_constant_loc, pull_constant_loc,
> +                                 num_push_constants, num_pull_constants,
> +                                 max_push_components, max_chunk_size,
> +                                 stage_prog_data);
>     }
>  
> +   /* As the uniforms are going to be reordered, take the data from a temporal
> +    * copy of the original param[].
> +    */
> +   gl_constant_value **param = rzalloc_array(mem_ctx, gl_constant_value*,
> +                                             stage_prog_data->nr_params);
> +   memcpy(param, stage_prog_data->param,
> +          sizeof(gl_constant_value*) * stage_prog_data->nr_params);
>     stage_prog_data->nr_params = num_push_constants;
>     stage_prog_data->nr_pull_params = num_pull_constants;
>  
> @@ -2139,7 +2191,7 @@ fs_visitor::assign_constant_locations()
>      * having to make a copy.
>      */
>     for (unsigned int i = 0; i < uniforms; i++) {
> -      const gl_constant_value *value = stage_prog_data->param[i];
> +      const gl_constant_value *value = param[i];
>  
>        if (pull_constant_loc[i] != -1) {
>           stage_prog_data->pull_param[pull_constant_loc[i]] = value;
> @@ -2147,6 +2199,7 @@ fs_visitor::assign_constant_locations()
>           stage_prog_data->param[push_constant_loc[i]] = value;
>        }
>     }
> +   ralloc_free(param);
>  }
>  
>  /**
> -- 
> 2.5.0
> 
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