[Mesa-dev] [PATCH v3 31/44] i965: Enable shared local memory for CS shared variables

[Iago Toral]

Reviewed-by: Iago Toral Quiroga <itoral at igalia.com>

On Tue, 2015-12-01 at 00:19 -0800, Jordan Justen wrote:
> v3:
>  * Check shared variable size at link time
> 
> Signed-off-by: Jordan Justen <jordan.l.justen at intel.com>
> Cc: Iago Toral Quiroga <itoral at igalia.com>
> ---
>  src/mesa/drivers/dri/i965/brw_cs.c        | 13 +++++++++++++
>  src/mesa/drivers/dri/i965/brw_defines.h   |  2 ++
>  src/mesa/drivers/dri/i965/gen7_cs_state.c | 12 ++++++++++++
>  3 files changed, 27 insertions(+)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_cs.c b/src/mesa/drivers/dri/i965/brw_cs.c
> index 9ef9bd4..d88e822 100644
> --- a/src/mesa/drivers/dri/i965/brw_cs.c
> +++ b/src/mesa/drivers/dri/i965/brw_cs.c
> @@ -107,6 +107,19 @@ brw_codegen_cs_prog(struct brw_context *brw,
>  
>     memset(&prog_data, 0, sizeof(prog_data));
>  
> +   if (prog->Comp.SharedSize > 64 * 1024) {
> +      prog->LinkStatus = false;
> +      const char *error_str =
> +         "Compute shader used more than 64KB of shared variables";
> +      ralloc_strcat(&prog->InfoLog, error_str);
> +      _mesa_problem(NULL, "Failed to link compute shader: %s\n", error_str);
> +
> +      ralloc_free(mem_ctx);
> +      return false;
> +   } else {
> +      prog_data.base.total_shared = prog->Comp.SharedSize;
> +   }
> +
>     assign_cs_binding_table_offsets(brw->intelScreen->devinfo, prog,
>                                     &cp->program.Base, &prog_data);
>  
> diff --git a/src/mesa/drivers/dri/i965/brw_defines.h b/src/mesa/drivers/dri/i965/brw_defines.h
> index 94f878b..ad4123e 100644
> --- a/src/mesa/drivers/dri/i965/brw_defines.h
> +++ b/src/mesa/drivers/dri/i965/brw_defines.h
> @@ -2865,6 +2865,8 @@ enum brw_wm_barycentric_interp_mode {
>  /* GEN7 DW5, GEN8+ DW6 */
>  # define MEDIA_BARRIER_ENABLE_SHIFT             21
>  # define MEDIA_BARRIER_ENABLE_MASK              INTEL_MASK(21, 21)
> +# define MEDIA_SHARED_LOCAL_MEMORY_SIZE_SHIFT   16
> +# define MEDIA_SHARED_LOCAL_MEMORY_SIZE_MASK    INTEL_MASK(20, 16)
>  # define MEDIA_GPGPU_THREAD_COUNT_SHIFT         0
>  # define MEDIA_GPGPU_THREAD_COUNT_MASK          INTEL_MASK(7, 0)
>  # define GEN8_MEDIA_GPGPU_THREAD_COUNT_SHIFT    0
> diff --git a/src/mesa/drivers/dri/i965/gen7_cs_state.c b/src/mesa/drivers/dri/i965/gen7_cs_state.c
> index 38b0258..c476047 100644
> --- a/src/mesa/drivers/dri/i965/gen7_cs_state.c
> +++ b/src/mesa/drivers/dri/i965/gen7_cs_state.c
> @@ -166,8 +166,20 @@ brw_upload_cs_state(struct brw_context *brw)
>        SET_FIELD(threads, GEN8_MEDIA_GPGPU_THREAD_COUNT) :
>        SET_FIELD(threads, MEDIA_GPGPU_THREAD_COUNT);
>     assert(threads <= brw->max_cs_threads);
> +
> +   assert(prog_data->total_shared <= 64 * 1024);
> +   uint32_t slm_size = 0;
> +   if (prog_data->total_shared > 0) {
> +      /* slm_size is in 4k increments, but must be a power of 2. */
> +      slm_size = 4 * 1024;
> +      while (slm_size < prog_data->total_shared)
> +         slm_size <<= 1;
> +      slm_size /= 4 * 1024;
> +   }
> +
>     desc[dw++] =
>        SET_FIELD(cs_prog_data->uses_barrier, MEDIA_BARRIER_ENABLE) |
> +      SET_FIELD(slm_size, MEDIA_SHARED_LOCAL_MEMORY_SIZE) |
>        media_threads;
>  
>     BEGIN_BATCH(4);