[Mesa-dev] [PATCH 2/4] nvc0/ir: don't dual issue instructions which depend on each other

[Ilia Mirkin]

On Sat, Aug 13, 2016 at 6:02 AM, Karol Herbst <karolherbst at gmail.com> wrote:
> no changes without a dual_issue pass
>
> changes with for ./GpuTest /test=pixmark_piano /benchmark /no_scorebox /msaa=0
> /benchmark_duration_ms=60000 /width=1024 /height=640:
>
> inst_executed: 1.03G
> inst_issued1: 538M -> 535M
> inst_issued2: 251M -> 254M
>
> score: 1038 -> 1052
>
> Signed-off-by: Karol Herbst <karolherbst at gmail.com>
> ---
>  src/gallium/drivers/nouveau/codegen/nv50_ir.cpp             | 11 +++++++++--
>  src/gallium/drivers/nouveau/codegen/nv50_ir.h               |  1 +
>  src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.cpp |  4 ++++
>  3 files changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir.cpp
> index 179ad0b..7a90cb7 100644
> --- a/src/gallium/drivers/nouveau/codegen/nv50_ir.cpp
> +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir.cpp
> @@ -893,12 +893,19 @@ insnCheckCommutationDefDef(const Instruction *a, const Instruction *b)
>  bool
>  Instruction::isCommutationLegal(const Instruction *i) const
>  {
> -   bool ret = insnCheckCommutationDefDef(this, i);
> -   ret = ret && insnCheckCommutationDefSrc(this, i);
> +   bool ret = !i->dependsOn(this);
>     ret = ret && insnCheckCommutationDefSrc(i, this);

This condition is covered by your new dependsOn() call. Did you mean
dependsOn to have something different? I haven't really thought
carefully about this yet.

>     return ret;
>  }
>
> +bool
> +Instruction::dependsOn(const Instruction *i) const
> +{
> +   bool ret = insnCheckCommutationDefDef(this, i);
> +   ret = ret && insnCheckCommutationDefSrc(i, this);
> +   return !ret;
> +}
> +
>  TexInstruction::TexInstruction(Function *fn, operation op)
>     : Instruction(fn, op, TYPE_F32)
>  {
> diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir.h b/src/gallium/drivers/nouveau/codegen/nv50_ir.h
> index 6d2ee8b..d81fca9 100644
> --- a/src/gallium/drivers/nouveau/codegen/nv50_ir.h
> +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir.h
> @@ -831,6 +831,7 @@ public:
>     bool isDead() const;
>     bool isNop() const;
>     bool isCommutationLegal(const Instruction *) const; // must be adjacent !
> +   bool dependsOn(const Instruction *) const; // weaker form of isCommutationLegal
>     bool isActionEqual(const Instruction *) const;
>     bool isResultEqual(const Instruction *) const;
>
> diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.cpp
> index faf2121..8ce8c19 100644
> --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.cpp
> +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.cpp
> @@ -620,6 +620,10 @@ bool TargetNVC0::canDualIssue(const Instruction *a, const Instruction *b) const
>        // not if the 2nd instruction isn't necessarily executed
>        if (clA == OPCLASS_TEXTURE || clA == OPCLASS_FLOW)
>           return false;
> +
> +      if (b->dependsOn(a))
> +         return false;
> +
>        // anything with MOV
>        if (a->op == OP_MOV || b->op == OP_MOV)
>           return true;
> --
> 2.9.2
>
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