[Mesa-dev] [Mesa-dev, 5/7] i965/cs: Initialize gl_LocalInvocationID in push constant data

Kristian Høgsberg krh at bitplanet.net
Thu Sep 10 11:33:24 PDT 2015


Jordan Justen <jordan.l.justen at intel.com> writes:

> Signed-off-by: Jordan Justen <jordan.l.justen at intel.com>
>
> ---
> src/mesa/drivers/dri/i965/brw_cs.cpp | 54 +++++++++++++++++++++++++++++++++---
>  1 file changed, 50 insertions(+), 4 deletions(-)
>
> diff --git a/src/mesa/drivers/dri/i965/brw_cs.cpp b/src/mesa/drivers/dri/i965/brw_cs.cpp
> index 541151a..9e51130 100644
> --- a/src/mesa/drivers/dri/i965/brw_cs.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_cs.cpp
> @@ -311,6 +311,7 @@ brw_upload_cs_state(struct brw_context *brw)
>     uint32_t offset;
>     uint32_t *desc = (uint32_t*) brw_state_batch(brw, AUB_TRACE_SURFACE_STATE,
>                                                  8 * 4, 64, &offset);
> +   struct gl_program *prog = (struct gl_program *) brw->compute_program;
>     struct brw_stage_state *stage_state = &brw->cs.base;
>     struct brw_cs_prog_data *cs_prog_data = brw->cs.prog_data;
>     struct brw_stage_prog_data *prog_data = &cs_prog_data->base;
> @@ -327,8 +328,16 @@ brw_upload_cs_state(struct brw_context *brw)
>                                              prog_data->binding_table.size_bytes,
>                                              32, &stage_state->bind_bo_offset);
>  
> +   unsigned local_id_dwords = 0;
> +
> +   if (prog->SystemValuesRead & SYSTEM_BIT_LOCAL_INVOCATION_ID) {
> +      local_id_dwords =
> +         brw_cs_prog_local_id_payload_size(prog, cs_prog_data->simd_size);
> +      local_id_dwords = ALIGN(local_id_dwords, 32) / sizeof(uint32_t);

We don't need the ALIGN() here - brw_cs_prog_local_id_payload_size() is
a multiple of dispatch_width (8, 16, or 32) and sizeof(uint32_t), so
it's always at least 32 byte aligned.  In fact, it looks like all uses
of brw_cs_prog_local_id_payload_size() want number of dwords, not
number of bytes, so maybe make that change?

> +   }
> +
>     unsigned push_constant_data_size =
> -      prog_data->nr_params * sizeof(gl_constant_value);
> +      (prog_data->nr_params + local_id_dwords) * sizeof(gl_constant_value);
>     unsigned reg_aligned_constant_size = ALIGN(push_constant_data_size, 32);
>     unsigned push_constant_regs = reg_aligned_constant_size / 32;
>     unsigned threads = get_cs_thread_count(cs_prog_data);
> @@ -451,6 +460,9 @@ const struct brw_tracked_state brw_cs_state = {
>   * Therefore, for SIMD8, we use 3 full registers, and for SIMD16 we use 6
>   * registers worth of push constant space.
>   *
> + * Note: Any updates to brw_cs_prog_local_id_payload_size or
> + * fill_local_id_payload need to coordinated.
> + *
>   * FINISHME: There are a few easy optimizations to consider.
>   *
>   * 1. If gl_WorkGroupSize x, y or z is 1, we can just use zero, and there is
> @@ -472,6 +484,27 @@ brw_cs_prog_local_id_payload_size(const struct gl_program *prog,
>  }
>  
>  
> +static void
> +fill_local_id_payload(const struct brw_cs_prog_data *cs_prog_data,
> +                      void *buffer, unsigned &x, unsigned &y, unsigned &z)
> +{

Avoid using C++ references here if we're planning to move it to a C
file?

> +   uint32_t *param = (uint32_t *)buffer;
> +   for (unsigned i = 0; i < cs_prog_data->simd_size; i++) {
> +      param[0 * cs_prog_data->simd_size + i] = x;
> +      param[1 * cs_prog_data->simd_size + i] = y;
> +      param[2 * cs_prog_data->simd_size + i] = z;
> +
> +      x = (x + 1) % cs_prog_data->local_size[0];

I think I'd prefer something like:

    x++;
    if (x == cs_prog_data->local_size[0]) {
       x = 0;
       y++;
       if (y == cs_prog_data->local_size[1]) {
          ...
       }
    }

which avoids the modulo per entry and looks a little more straightforward.

With those changes,

Reviewed-by: Kristian Høgsberg <krh at bitplanet.net>

> +      if (x == 0) {
> +         y = (y + 1) % cs_prog_data->local_size[1];
> +         if (y == 0) {
> +            z = (z + 1) % cs_prog_data->local_size[2];
> +         }
> +      }
> +   }
> +}
> +
> +
>  /**
>   * Creates a region containing the push constants for the CS on gen7+.
>   *
> @@ -492,6 +525,13 @@ brw_upload_cs_push_constants(struct brw_context *brw,
>     struct gl_context *ctx = &brw->ctx;
>     const struct brw_stage_prog_data *prog_data =
>        (brw_stage_prog_data*) cs_prog_data;
> +   unsigned local_id_dwords = 0;
> +
> +   if (prog->SystemValuesRead & SYSTEM_BIT_LOCAL_INVOCATION_ID) {
> +      local_id_dwords =
> +         brw_cs_prog_local_id_payload_size(prog, cs_prog_data->simd_size);
> +      local_id_dwords = ALIGN(local_id_dwords, 32) / sizeof(uint32_t);
> +   }
>  
>     /* Updates the ParamaterValues[i] pointers for all parameters of the
>      * basic type of PROGRAM_STATE_VAR.
> @@ -499,14 +539,14 @@ brw_upload_cs_push_constants(struct brw_context *brw,
>     /* XXX: Should this happen somewhere before to get our state flag set? */
>     _mesa_load_state_parameters(ctx, prog->Parameters);
>  
> -   if (prog_data->nr_params == 0) {
> +   if (prog_data->nr_params == 0 && local_id_dwords == 0) {
>        stage_state->push_const_size = 0;
>     } else {
>        gl_constant_value *param;
>        unsigned i, t;
>  
>        const unsigned push_constant_data_size =
> -         prog_data->nr_params * sizeof(gl_constant_value);
> +         (local_id_dwords + prog_data->nr_params) * sizeof(gl_constant_value);
>        const unsigned reg_aligned_constant_size = ALIGN(push_constant_data_size, 32);
>        const unsigned param_aligned_count =
>           reg_aligned_constant_size / sizeof(*param);
> @@ -522,9 +562,15 @@ brw_upload_cs_push_constants(struct brw_context *brw,
>        STATIC_ASSERT(sizeof(gl_constant_value) == sizeof(float));
>  
>        /* _NEW_PROGRAM_CONSTANTS */
> +      unsigned x = 0, y = 0, z = 0;
>        for (t = 0; t < threads; t++) {
> +         gl_constant_value *next_param = &param[t * param_aligned_count];
> +         if (local_id_dwords > 0) {
> +            fill_local_id_payload(cs_prog_data, (void*)next_param, x, y, z);
> +            next_param += local_id_dwords;
> +         }
>           for (i = 0; i < prog_data->nr_params; i++) {
> -            param[t * param_aligned_count + i] = *prog_data->param[i];
> +            next_param[i] = *prog_data->param[i];
>           }
>        }
>  


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