[Mesa-dev] [PATCH] nvc0/ir: always use CG mode for loads from atomic-only buffers

[Karol Herbst]

Reviewed-by: Karol Herbst <kherbst at redhat.com>

On Sun, Feb 3, 2019 at 4:10 PM Ilia Mirkin <imirkin at alum.mit.edu> wrote:
>
> Atomic operations don't update the local cache, which means that we
> would have to issue CCTL operations in order to get the updated values.
> When we know that a buffer is primarily used for atomic operations, it's
> easier to just avoid the caching at that level entirely.
>
> The same issue persists for non-atomic buffers, which will have to be
> fixed separately.
>
> Fixes the failing dEQP-GLES31.functional.atomic_counter.* tests.
>
> Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
> ---
>  .../drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp  | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
> index afd7916a321..335e708c5cb 100644
> --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
> +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
> @@ -1087,6 +1087,8 @@ public:
>     };
>     std::vector<MemoryFile> memoryFiles;
>
> +   std::vector<bool> bufferAtomics;
> +
>  private:
>     int inferSysValDirection(unsigned sn) const;
>     bool scanDeclaration(const struct tgsi_full_declaration *);
> @@ -1137,6 +1139,7 @@ bool Source::scanSource()
>     //resources.resize(scan.file_max[TGSI_FILE_RESOURCE] + 1);
>     tempArrayId.resize(scan.file_max[TGSI_FILE_TEMPORARY] + 1);
>     memoryFiles.resize(scan.file_max[TGSI_FILE_MEMORY] + 1);
> +   bufferAtomics.resize(scan.file_max[TGSI_FILE_BUFFER] + 1);
>
>     info->immd.bufSize = 0;
>
> @@ -1483,11 +1486,14 @@ bool Source::scanDeclaration(const struct tgsi_full_declaration *decl)
>           tempArrayInfo.insert(std::make_pair(arrayId, std::make_pair(
>                                                     first, last - first + 1)));
>        break;
> +   case TGSI_FILE_BUFFER:
> +      for (i = first; i <= last; ++i)
> +         bufferAtomics[i] = decl->Declaration.Atomic;
> +      break;
>     case TGSI_FILE_ADDRESS:
>     case TGSI_FILE_CONSTANT:
>     case TGSI_FILE_IMMEDIATE:
>     case TGSI_FILE_SAMPLER:
> -   case TGSI_FILE_BUFFER:
>     case TGSI_FILE_IMAGE:
>        break;
>     default:
> @@ -2720,7 +2726,11 @@ Converter::handleLOAD(Value *dst0[4])
>           }
>
>           Instruction *ld = mkLoad(TYPE_U32, dst0[c], sym, off);
> -         ld->cache = tgsi.getCacheMode();
> +         if (tgsi.getSrc(0).getFile() == TGSI_FILE_BUFFER &&
> +             code->bufferAtomics[r])
> +            ld->cache = nv50_ir::CACHE_CG;
> +         else
> +            ld->cache = tgsi.getCacheMode();
>           if (ind)
>              ld->setIndirect(0, 1, ind);
>        }
> --
> 2.19.2
>
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