[Mesa-dev] [PATCH v4 09/12] i965: Support new local ID push constant & cross-thread constants

Jason Ekstrand jason at jlekstrand.net
Wed Jun 1 22:56:57 UTC 2016


On Wed, Jun 1, 2016 at 3:04 PM, Jordan Justen <jordan.l.justen at intel.com>
wrote:

> The cross thread constant support appears on Haswell. It allows us to
> upload a set of uniform data for all threads without duplicating it
> per thread.
>
> We also support per-thread data which allows us to store a per-thread
> ID in one of the uniforms that can be used to calculate the
> gl_LocalInvocationIndex and gl_LocalInvocationID variables.
>
> v4:
>  * Support the old local ID push constant layout as well (Jason)
>
> Signed-off-by: Jordan Justen <jordan.l.justen at intel.com>
> ---
>  src/mesa/drivers/dri/i965/brw_defines.h   |  3 +
>  src/mesa/drivers/dri/i965/gen7_cs_state.c | 99
> +++++++++++++++++--------------
>  2 files changed, 56 insertions(+), 46 deletions(-)
>
> diff --git a/src/mesa/drivers/dri/i965/brw_defines.h
> b/src/mesa/drivers/dri/i965/brw_defines.h
> index 4eb6b1f..e7d1a9f 100644
> --- a/src/mesa/drivers/dri/i965/brw_defines.h
> +++ b/src/mesa/drivers/dri/i965/brw_defines.h
> @@ -2943,6 +2943,9 @@ enum brw_wm_barycentric_interp_mode {
>  # define MEDIA_GPGPU_THREAD_COUNT_MASK          INTEL_MASK(7, 0)
>  # define GEN8_MEDIA_GPGPU_THREAD_COUNT_SHIFT    0
>  # define GEN8_MEDIA_GPGPU_THREAD_COUNT_MASK     INTEL_MASK(9, 0)
> +/* GEN7 DW6, GEN8+ DW7 */
> +# define CROSS_THREAD_READ_LENGTH_SHIFT         0
> +# define CROSS_THREAD_READ_LENGTH_MASK          INTEL_MASK(7, 0)
>  #define MEDIA_STATE_FLUSH                       0x7004
>  #define GPGPU_WALKER                            0x7105
>  /* GEN7 DW0 */
> diff --git a/src/mesa/drivers/dri/i965/gen7_cs_state.c
> b/src/mesa/drivers/dri/i965/gen7_cs_state.c
> index 619edfb..2fee02d 100644
> --- a/src/mesa/drivers/dri/i965/gen7_cs_state.c
> +++ b/src/mesa/drivers/dri/i965/gen7_cs_state.c
> @@ -42,7 +42,6 @@ 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;
> @@ -59,16 +58,6 @@ 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 = cs_prog_data->local_invocation_id_regs * 8;
> -
> -   unsigned push_constant_data_size =
> -      (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;
> -
>     uint32_t dwords = brw->gen < 8 ? 8 : 9;
>     BEGIN_BATCH(dwords);
>     OUT_BATCH(MEDIA_VFE_STATE << 16 | (dwords - 2));
> @@ -118,7 +107,8 @@ brw_upload_cs_state(struct brw_context *brw)
>      * Note: The constant data is built in brw_upload_cs_push_constants
> below.
>      */
>     const uint32_t vfe_curbe_allocation =
> -      push_constant_regs * cs_prog_data->threads;
> +      ALIGN(cs_prog_data->push.per_thread.regs * cs_prog_data->threads +
> +            cs_prog_data->push.cross_thread.regs, 2);
>     OUT_BATCH(SET_FIELD(vfe_urb_allocation, MEDIA_VFE_STATE_URB_ALLOC) |
>               SET_FIELD(vfe_curbe_allocation,
> MEDIA_VFE_STATE_CURBE_ALLOC));
>     OUT_BATCH(0);
> @@ -126,11 +116,11 @@ brw_upload_cs_state(struct brw_context *brw)
>     OUT_BATCH(0);
>     ADVANCE_BATCH();
>
> -   if (reg_aligned_constant_size > 0) {
> +   if (cs_prog_data->push.total.size > 0) {
>        BEGIN_BATCH(4);
>        OUT_BATCH(MEDIA_CURBE_LOAD << 16 | (4 - 2));
>        OUT_BATCH(0);
> -      OUT_BATCH(ALIGN(reg_aligned_constant_size * cs_prog_data->threads,
> 64));
> +      OUT_BATCH(ALIGN(cs_prog_data->push.total.size, 64));
>        OUT_BATCH(stage_state->push_const_offset);
>        ADVANCE_BATCH();
>     }
> @@ -149,7 +139,8 @@ brw_upload_cs_state(struct brw_context *brw)
>     desc[dw++] = stage_state->sampler_offset |
>        ((stage_state->sampler_count + 3) / 4);
>     desc[dw++] = stage_state->bind_bo_offset;
> -   desc[dw++] = SET_FIELD(push_constant_regs, MEDIA_CURBE_READ_LENGTH);
> +   desc[dw++] = SET_FIELD(cs_prog_data->push.per_thread.regs,
> +                          MEDIA_CURBE_READ_LENGTH);
>     const uint32_t media_threads =
>        brw->gen >= 8 ?
>        SET_FIELD(cs_prog_data->threads, GEN8_MEDIA_GPGPU_THREAD_COUNT) :
> @@ -171,6 +162,10 @@ brw_upload_cs_state(struct brw_context *brw)
>        SET_FIELD(slm_size, MEDIA_SHARED_LOCAL_MEMORY_SIZE) |
>        media_threads;
>
> +   desc[dw++] =
> +      SET_FIELD(cs_prog_data->push.cross_thread.regs,
> +                CROSS_THREAD_READ_LENGTH);
>

I don't think this needs 3 lines.


> +
>     BEGIN_BATCH(4);
>     OUT_BATCH(MEDIA_INTERFACE_DESCRIPTOR_LOAD << 16 | (4 - 2));
>     OUT_BATCH(0);
> @@ -213,10 +208,6 @@ brw_upload_cs_push_constants(struct brw_context *brw,
>     struct gl_context *ctx = &brw->ctx;
>     const struct brw_stage_prog_data *prog_data =
>        (struct brw_stage_prog_data*) cs_prog_data;
> -   unsigned local_id_dwords = 0;
> -
> -   if (prog->SystemValuesRead & SYSTEM_BIT_LOCAL_INVOCATION_ID)
> -      local_id_dwords = cs_prog_data->local_invocation_id_regs * 8;
>
>     /* Updates the ParamaterValues[i] pointers for all parameters of the
>      * basic type of PROGRAM_STATE_VAR.
> @@ -224,41 +215,57 @@ 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 && local_id_dwords == 0) {
> +   if (cs_prog_data->push.total.size == 0) {
>        stage_state->push_const_size = 0;
> -   } else {
> -      gl_constant_value *param;
> -      unsigned i, t;
> -
> -      const unsigned push_constant_data_size =
> -         (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);
> +      return;
> +   }
>
> -      param = (gl_constant_value*)
> -         brw_state_batch(brw, type,
> -                         ALIGN(reg_aligned_constant_size *
> -                                  cs_prog_data->threads, 64),
> -                         64, &stage_state->push_const_offset);
> -      assert(param);
>
> -      STATIC_ASSERT(sizeof(gl_constant_value) == sizeof(float));
> +   gl_constant_value *param;
> +   param = (gl_constant_value*)
>

These could go on the same line.


> +      brw_state_batch(brw, type,
> +                      ALIGN(cs_prog_data->push.total.size, 64),
> +                      64, &stage_state->push_const_offset);
> +   assert(param);
> +
> +   STATIC_ASSERT(sizeof(gl_constant_value) == sizeof(float));
> +
> +   if (cs_prog_data->push.cross_thread.size > 0) {
> +      gl_constant_value *param_copy = param;
> +      assert(cs_prog_data->thread_local_id_index < 0 ||
> +             cs_prog_data->thread_local_id_index >=
> +                cs_prog_data->push.cross_thread.dwords);
> +      for (unsigned i = 0;
> +           i < cs_prog_data->push.cross_thread.dwords;
> +           i++) {
> +         param_copy[i] = *prog_data->param[i];
> +      }
> +   }
>
> +   gl_constant_value thread_id;
> +   if (cs_prog_data->push.per_thread.size > 0) {
>        brw_cs_fill_local_id_payload(cs_prog_data, param,
> cs_prog_data->threads,
> -                                   reg_aligned_constant_size);
> -
> -      /* _NEW_PROGRAM_CONSTANTS */
> -      for (t = 0; t < cs_prog_data->threads; t++) {
> -         gl_constant_value *next_param =
> -            &param[t * param_aligned_count + local_id_dwords];
> -         for (i = 0; i < prog_data->nr_params; i++) {
> -            next_param[i] = *prog_data->param[i];
> +                                   cs_prog_data->push.per_thread.size);
> +      for (unsigned t = 0; t < cs_prog_data->threads; t++) {
> +         unsigned dst =
> +            8 * (cs_prog_data->push.per_thread.regs * t +
> +                 cs_prog_data->push.cross_thread.regs +
> +                 cs_prog_data->local_invocation_id_regs);
> +         unsigned src = cs_prog_data->push.cross_thread.dwords;
> +         for ( ; src < prog_data->nr_params; src++, dst++) {
> +            if (src != cs_prog_data->thread_local_id_index)
> +               param[dst] = *prog_data->param[src];
> +            else {
> +               thread_id.u = t * cs_prog_data->simd_size;
> +               param[dst] = thread_id;
> +            }
>           }
>        }
> -
> -      stage_state->push_const_size = ALIGN(prog_data->nr_params, 8) / 8;
>     }
> +
> +   stage_state->push_const_size =
> +      cs_prog_data->push.cross_thread.regs +
> +      cs_prog_data->push.per_thread.regs;
>  }
>
>
> --
> 2.8.1
>
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