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[Triton-MLIR][BACKEND] Fix the membar pass to add missing barriers caused by scf.for (#933)

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1. Add missing barriers and revert the previous temporary solution
2. Extract the `run` method from membar analysis because the membar
analysis should have two phases, including construction, which doesn't
modify any IR, and modification, which adds barrier IRs. Hope this could
make the use of membar clear.
This commit is contained in:
Keren Zhou
2022-12-01 11:54:18 -08:00
committed by GitHub
parent 9def1bcebf
commit c280ebda1b
8 changed files with 170 additions and 102 deletions
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48
test/Analysis/test-membar.mlir
View File

@@ -261,9 +261,9 @@ func @for_alias(%lb : index, %ub : index, %step : index, %A : !tt.ptr<f16>, %B :
%cst0 = tt.cat %a_shared_init, %b_shared_init {axis = 0} : (tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>) -> tensor<256x32xf16, #A_SHARED>
%c_shared_init = arith.constant dense<0.00e+00> : tensor<128x32xf16, #A_SHARED>
%a_shared, %b_shared, %c_shared = scf.for %iv = %lb to %ub step %step iter_args(%a_shared = %a_shared_init, %b_shared = %b_shared_init, %c_shared = %c_shared_init) -> (tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>) {
%cst1 = tt.cat %a_shared_init, %b_shared_init {axis = 0} : (tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>) -> tensor<256x32xf16, #A_SHARED>
%cst1 = tt.cat %a_shared_init, %b_shared_init {axis = 0} : (tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>) -> tensor<256x32xf16, #AL>
// CHECK-NEXT: Membar 6
%cst2 = tt.cat %a_shared, %b_shared {axis = 0} : (tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>) -> tensor<256x32xf16, #A_SHARED>
%cst2 = tt.cat %a_shared, %b_shared {axis = 0} : (tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>) -> tensor<256x32xf16, #AL>
scf.yield %c_shared, %a_shared, %b_shared : tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>
}
// CHECK-NEXT: Membar 9
@@ -271,4 +271,48 @@ func @for_alias(%lb : index, %ub : index, %step : index, %A : !tt.ptr<f16>, %B :
return
}
// Although cst2 is not an argument of scf.yield, its memory is reused by cst1.
// So we need a barrier both before and after cst1
// CHECK-LABEL: for_reuse
func @for_reuse(%lb : index, %ub : index, %step : index, %A : !tt.ptr<f16>, %B : !tt.ptr<f16>) {
%a_shared_init = arith.constant dense<0.00e+00> : tensor<128x32xf16, #A_SHARED>
%b_shared_init = arith.constant dense<0.00e+00> : tensor<128x32xf16, #A_SHARED>
// CHECK-NEXT: Membar 2
%cst0 = tt.cat %a_shared_init, %b_shared_init {axis = 0} : (tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>) -> tensor<256x32xf16, #A_SHARED>
%c_shared_init = arith.constant dense<0.00e+00> : tensor<128x32xf16, #A_SHARED>
%a_shared, %b_shared, %c_shared = scf.for %iv = %lb to %ub step %step iter_args(%a_shared = %a_shared_init, %b_shared = %b_shared_init, %c_shared = %c_shared_init) -> (tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>) {
// CHECK-NEXT: Membar 5
%cst1 = tt.cat %a_shared_init, %b_shared_init {axis = 0} : (tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>) -> tensor<256x32xf16, #A_SHARED>
// CHECK-NEXT: Membar 7
%cst2 = tt.cat %a_shared, %b_shared {axis = 0} : (tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>) -> tensor<256x32xf16, #A_SHARED>
scf.yield %c_shared, %a_shared, %b_shared : tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>
}
// CHECK-NEXT: Membar 10
%cst3 = tt.cat %cst0, %cst0 {axis = 0} : (tensor<256x32xf16, #A_SHARED>, tensor<256x32xf16, #A_SHARED>) -> tensor<512x32xf16, #A_SHARED>
return
}
// CHECK-LABEL: for_reuse_nested
func @for_reuse_nested(%lb : index, %ub : index, %step : index, %A : !tt.ptr<f16>, %B : !tt.ptr<f16>) {
%a_shared_init = arith.constant dense<0.00e+00> : tensor<128x32xf16, #A_SHARED>
%b_shared_init = arith.constant dense<0.00e+00> : tensor<128x32xf16, #A_SHARED>
// CHECK-NEXT: Membar 2
%cst0 = tt.cat %a_shared_init, %b_shared_init {axis = 0} : (tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>) -> tensor<256x32xf16, #A_SHARED>
%c_shared_init = arith.constant dense<0.00e+00> : tensor<128x32xf16, #A_SHARED>
%a_shared, %b_shared, %c_shared = scf.for %iv = %lb to %ub step %step iter_args(%a_shared = %a_shared_init, %b_shared = %b_shared_init, %c_shared = %c_shared_init) -> (tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>) {
// CHECK-NEXT: Membar 5
%cst1 = tt.cat %a_shared_init, %b_shared_init {axis = 0} : (tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>) -> tensor<256x32xf16, #A_SHARED>
%a_shared_next, %b_shared_next, %c_shared_next = scf.for %ivv = %lb to %ub step %step iter_args(%a_shared_nested = %a_shared_init, %b_shared_nested = %b_shared_init, %c_shared_nested = %c_shared_init) -> (tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>) {
// CHECK-NEXT: Membar 7
%cst2 = tt.cat %a_shared_nested, %b_shared_nested {axis = 0} : (tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>) -> tensor<256x32xf16, #A_SHARED>
scf.yield %c_shared_nested, %a_shared_nested, %b_shared_nested : tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>
}
scf.yield %c_shared, %a_shared, %b_shared : tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>, tensor<128x32xf16, #A_SHARED>
}
// CHECK-NEXT: Membar 11
%cst3 = tt.cat %cst0, %cst0 {axis = 0} : (tensor<256x32xf16, #A_SHARED>, tensor<256x32xf16, #A_SHARED>) -> tensor<512x32xf16, #A_SHARED>
return
}
}

4
test/lib/Analysis/TestMembar.cpp
View File

@@ -26,7 +26,9 @@ struct TestMembarPass
auto op_name = SymbolTable::getSymbolName(operation).getValue().str();
os << op_name << "\n";
Allocation allocation(operation);
MembarAnalysis analysis(&allocation);
MembarAnalysis membarPass(&allocation);
membarPass.run();
size_t operationId = 0;
operation->walk<WalkOrder::PreOrder>([&](Operation *op) {
if (isa<gpu::BarrierOp>(op)) {