[Mesa-dev] [PATCH] gm107/ir: emit RED instead of ATOM when no dst

[Samuel Pitoiset]

On 11/04/2016 07:21 PM, Pierre Moreau wrote:
> Are reduction doable on shared atomics as well?

AFAIK, no.

>
> Pierre
>
> On 08:08 pm - Nov 04 2016, Samuel Pitoiset wrote:
>> This is similar to NVC0 and GK110 emitters where we emit
>> reduction operations instead of atomic operations when the
>> destination is not used.
>>
>> Found after writing some tests which check if performance counters
>> return the expected value. In that case, gred_count returned 0
>> on gm107 while at least gk106 returned the correct value.
>>
>> Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
>> ---
>>  .../drivers/nouveau/codegen/nv50_ir_emit_gm107.cpp | 29 +++++++++++++++++++++-
>>  1 file changed, 28 insertions(+), 1 deletion(-)
>>
>> diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_gm107.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_gm107.cpp
>> index 5ed2ad4..5bd0fa0 100644
>> --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_gm107.cpp
>> +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_gm107.cpp
>> @@ -180,6 +180,7 @@ private:
>>     void emitIPA();
>>     void emitATOM();
>>     void emitATOMS();
>> +   void emitRED();
>>     void emitCCTL();
>>
>>     void emitPIXLD();
>> @@ -2496,6 +2497,29 @@ CodeEmitterGM107::emitATOMS()
>>  }
>>
>>  void
>> +CodeEmitterGM107::emitRED()
>> +{
>> +   unsigned dType;
>> +
>> +   switch (insn->dType) {
>> +   case TYPE_U32: dType = 0; break;
>> +   case TYPE_S32: dType = 1; break;
>> +   case TYPE_U64: dType = 2; break;
>> +   case TYPE_F32: dType = 3; break;
>> +   case TYPE_B128: dType = 4; break;
>> +   case TYPE_S64: dType = 5; break;
>> +   default: assert(!"unexpected dType"); dType = 0; break;
>> +   }
>> +
>> +   emitInsn (0xebf80000);
>> +   emitField(0x30, 1, insn->src(0).getIndirect(0)->getSize() == 8);
>> +   emitField(0x17, 3, insn->subOp);
>> +   emitField(0x14, 3, dType);
>> +   emitADDR (0x08, 0x1c, 20, 0, insn->src(0));
>> +   emitGPR  (0x00, insn->src(1));
>> +}
>> +
>> +void
>>  CodeEmitterGM107::emitCCTL()
>>  {
>>     unsigned width;
>> @@ -3237,7 +3261,10 @@ CodeEmitterGM107::emitInstruction(Instruction *i)
>>        if (insn->src(0).getFile() == FILE_MEMORY_SHARED)
>>           emitATOMS();
>>        else
>> -         emitATOM();
>> +         if (!insn->defExists(0) && insn->subOp < NV50_IR_SUBOP_ATOM_CAS)
>> +            emitRED();
>> +         else
>> +            emitATOM();
>>        break;
>>     case OP_CCTL:
>>        emitCCTL();
>> --
>> 2.10.1
>>
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