[Mlir-commits] [mlir] [mlir][mesh] adding option for traversal order in sharding propagation (PR #144079)
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llvmlistbot at llvm.org
Fri Jun 13 07:04:29 PDT 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-mlir
Author: Frank Schlimbach (fschlimb)
<details>
<summary>Changes</summary>
The traversal order in sharding propagation was hard-coded. This PR provides options to the pass to select a suitable order
- forward-only
- backward-only
- forward-backward
- backward-forward
Default is the previous behavior (backward-forward).
FYI @<!-- -->tkarna
---
Full diff: https://github.com/llvm/llvm-project/pull/144079.diff
5 Files Affected:
- (modified) mlir/include/mlir/Dialect/Mesh/Transforms/Passes.h (+12)
- (modified) mlir/include/mlir/Dialect/Mesh/Transforms/Passes.td (+15)
- (modified) mlir/include/mlir/Transforms/Passes.h (+1)
- (modified) mlir/lib/Dialect/Mesh/Transforms/ShardingPropagation.cpp (+30-10)
- (added) mlir/test/Dialect/Mesh/forward-sharding-propagation.mlir (+49)
``````````diff
diff --git a/mlir/include/mlir/Dialect/Mesh/Transforms/Passes.h b/mlir/include/mlir/Dialect/Mesh/Transforms/Passes.h
index 83399d10beaae..a2424d43a8ba9 100644
--- a/mlir/include/mlir/Dialect/Mesh/Transforms/Passes.h
+++ b/mlir/include/mlir/Dialect/Mesh/Transforms/Passes.h
@@ -19,6 +19,18 @@ class FuncOp;
namespace mesh {
+/// This enum controls the traversal order for the sharding propagation.
+enum class TraversalOrder {
+ /// Forward traversal.
+ Forward,
+ /// Backward traversal.
+ Backward,
+ /// Forward then backward traversal.
+ ForwardBackward,
+ /// Backward then forward traversal.
+ BackwardForward
+};
+
//===----------------------------------------------------------------------===//
// Passes
//===----------------------------------------------------------------------===//
diff --git a/mlir/include/mlir/Dialect/Mesh/Transforms/Passes.td b/mlir/include/mlir/Dialect/Mesh/Transforms/Passes.td
index 06ebf151e7d64..11ec7e78cd5e6 100644
--- a/mlir/include/mlir/Dialect/Mesh/Transforms/Passes.td
+++ b/mlir/include/mlir/Dialect/Mesh/Transforms/Passes.td
@@ -24,6 +24,21 @@ def ShardingPropagation : InterfacePass<"sharding-propagation", "mlir::FunctionO
operation, and the operations themselves are added with sharding option
attributes.
}];
+ let options = [
+ Option<"traversal", "traversal",
+ "mlir::mesh::TraversalOrder", /*default=*/"mlir::mesh::TraversalOrder::BackwardForward",
+ "Traversal order to use for sharding propagation:",
+ [{::llvm::cl::values(
+ clEnumValN(mlir::mesh::TraversalOrder::Forward, "forward",
+ "Forward only traversal."),
+ clEnumValN(mlir::mesh::TraversalOrder::Backward, "backward",
+ "backward only traversal."),
+ clEnumValN(mlir::mesh::TraversalOrder::ForwardBackward, "forward-backward",
+ "forward-backward traversal."),
+ clEnumValN(mlir::mesh::TraversalOrder::BackwardForward, "backward-forward",
+ "backward-forward traversal.")
+ )}]>,
+ ];
let dependentDialects = [
"mesh::MeshDialect"
];
diff --git a/mlir/include/mlir/Transforms/Passes.h b/mlir/include/mlir/Transforms/Passes.h
index 41f208216374f..16cdbebf91900 100644
--- a/mlir/include/mlir/Transforms/Passes.h
+++ b/mlir/include/mlir/Transforms/Passes.h
@@ -18,6 +18,7 @@
#include "mlir/Pass/PassManager.h"
#include "mlir/Transforms/GreedyPatternRewriteDriver.h"
#include "mlir/Transforms/LocationSnapshot.h"
+// #include "mlir/Transforms/ShardingPropagationUtils.h"
#include "mlir/Transforms/ViewOpGraph.h"
#include "llvm/Support/Debug.h"
#include <limits>
diff --git a/mlir/lib/Dialect/Mesh/Transforms/ShardingPropagation.cpp b/mlir/lib/Dialect/Mesh/Transforms/ShardingPropagation.cpp
index 4452dd65fce9d..9d4a144912ee2 100644
--- a/mlir/lib/Dialect/Mesh/Transforms/ShardingPropagation.cpp
+++ b/mlir/lib/Dialect/Mesh/Transforms/ShardingPropagation.cpp
@@ -362,6 +362,9 @@ static LogicalResult visitOp(Operation *op, OpBuilder &builder) {
//===----------------------------------------------------------------------===//
struct ShardingPropagation
: public mesh::impl::ShardingPropagationBase<ShardingPropagation> {
+
+ using ShardingPropagationBase<ShardingPropagation>::ShardingPropagationBase;
+
void runOnOperation() override {
FunctionOpInterface funcOp = getOperation();
MLIRContext *ctx = funcOp.getContext();
@@ -383,17 +386,34 @@ struct ShardingPropagation
});
// 1. propagate in reversed order
- for (Operation &op : llvm::make_early_inc_range(llvm::reverse(block)))
- if (failed(visitOp(&op, builder)))
- return signalPassFailure();
-
- LLVM_DEBUG(DBGS() << "After reversed order propagation:\n"
- << funcOp << "\n");
- LLVM_DEBUG(assert(succeeded(mlir::verify(funcOp))));
+ if (traversal == TraversalOrder::Backward ||
+ traversal == TraversalOrder::BackwardForward) {
+ for (Operation &op : llvm::make_early_inc_range(llvm::reverse(block)))
+ if (failed(visitOp(&op, builder)))
+ return signalPassFailure();
+ if (traversal == TraversalOrder::BackwardForward) {
+ LLVM_DEBUG(DBGS() << "After backward order propagation:\n"
+ << funcOp << "\n");
+ LLVM_DEBUG(assert(succeeded(mlir::verify(funcOp))));
+ }
+ }
// 2. propagate in original order
- for (Operation &op : llvm::make_early_inc_range(block))
- if (failed(visitOp(&op, builder)))
- return signalPassFailure();
+ if (traversal != TraversalOrder::Backward) {
+ for (Operation &op : llvm::make_early_inc_range(block))
+ if (failed(visitOp(&op, builder)))
+ return signalPassFailure();
+ if (traversal == TraversalOrder::ForwardBackward) {
+ LLVM_DEBUG(DBGS() << "After forward order propagation:\n"
+ << funcOp << "\n");
+ LLVM_DEBUG(assert(succeeded(mlir::verify(funcOp))));
+ }
+ }
+
+ // 3. propagate in backward order if needed
+ if (traversal == TraversalOrder::ForwardBackward)
+ for (Operation &op : llvm::make_early_inc_range(llvm::reverse(block)))
+ if (failed(visitOp(&op, builder)))
+ return signalPassFailure();
}
};
diff --git a/mlir/test/Dialect/Mesh/forward-sharding-propagation.mlir b/mlir/test/Dialect/Mesh/forward-sharding-propagation.mlir
new file mode 100644
index 0000000000000..98e9931b8de94
--- /dev/null
+++ b/mlir/test/Dialect/Mesh/forward-sharding-propagation.mlir
@@ -0,0 +1,49 @@
+// RUN: mlir-opt --pass-pipeline="builtin.module(func.func(sharding-propagation{traversal=forward}))" %s | FileCheck %s
+
+#map = affine_map<(d0, d1) -> (d0, d1)>
+module attributes {dlti.map = #dlti.map<"MPI:Implementation" = "mpich", "MPI:comm_world_rank" = 0 : i32>} {
+ mesh.mesh @mesh(shape = 1) {sym_visibility = "private"}
+ func.func @test_forward() -> (tensor<6x6xi32>, tensor<6x6xi32>, tensor<i32>) attributes {llvm.emit_c_interface} {
+ %c1_i32 = arith.constant 1 : i32
+ // CHECK: [[v3:%.*]] = tensor.empty() : tensor<6x6xi32>
+ %0 = tensor.empty() : tensor<6x6xi32>
+ // CHECK: [[v1:%.*]] = linalg.fill ins
+ // CHECK: [[vsharding_0:%.*]] = mesh.sharding @mesh split_axes = {{\[\[}}0]] : !mesh.sharding
+ // CHECK: [[vsharding_annotated_1:%.*]] = mesh.shard [[v1]] to [[vsharding_0]] : tensor<6x6xi32>
+ %1 = linalg.fill ins(%c1_i32 : i32) outs(%0 : tensor<6x6xi32>) -> tensor<6x6xi32>
+ %sharding = mesh.sharding @mesh split_axes = [[0]] : !mesh.sharding
+ %sharding_annotated = mesh.shard %1 to %sharding : tensor<6x6xi32>
+ // CHECK: [[v2:%.*]] = tensor.empty() : tensor<6x6xi32>
+ // CHECK: [[vsharding_2:%.*]] = mesh.sharding @mesh split_axes = {{\[\[}}0]] : !mesh.sharding
+ // CHECK: [[vsharding_annotated_3:%.*]] = mesh.shard [[vsharding_annotated_1]] to [[vsharding_2]] annotate_for_users : tensor<6x6xi32>
+ %3 = tensor.empty() : tensor<6x6xi32>
+ // CHECK: [[vsharding_4:%.*]] = mesh.sharding @mesh split_axes = {{\[\[}}0]] : !mesh.sharding
+ // CHECK: [[vsharding_annotated_5:%.*]] = mesh.shard [[v2]] to [[vsharding_4]] annotate_for_users : tensor<6x6xi32>
+ // CHECK: [[v3:%.*]] = linalg.generic {indexing_maps = [#map, #map, #map], iterator_types = ["parallel", "parallel"]}
+ // CHECK-SAME: ins([[vsharding_annotated_3]], [[vsharding_annotated_3]] : tensor<6x6xi32>, tensor<6x6xi32>) outs([[vsharding_annotated_5]] : tensor<6x6xi32>) {
+ // CHECK: [[vsharding_6:%.*]] = mesh.sharding @mesh split_axes = {{\[\[}}0]] : !mesh.sharding
+ // CHECK: [[vsharding_annotated_7:%.*]] = mesh.shard [[v3]] to [[vsharding_6]] : tensor<6x6xi32>
+ %4 = linalg.generic {indexing_maps = [#map, #map, #map], iterator_types = ["parallel", "parallel"]} ins(%sharding_annotated, %sharding_annotated
+ : tensor<6x6xi32>, tensor<6x6xi32>) outs(%3 : tensor<6x6xi32>) {
+ ^bb0(%in: i32, %in_2: i32, %out: i32):
+ %9 = arith.addi %in, %in_2 : i32
+ linalg.yield %9 : i32
+ } -> tensor<6x6xi32>
+ %c0_i32 = arith.constant 0 : i32
+ %6 = tensor.empty() : tensor<i32>
+ %7 = linalg.fill ins(%c0_i32 : i32) outs(%6 : tensor<i32>) -> tensor<i32>
+ // CHECK: [[vreduced:%.*]] = linalg.reduce ins
+ // CHECK: [[vsharding_12:%.*]] = mesh.sharding @mesh split_axes = [] partial = sum [0] : !mesh.sharding
+ // CHECK: [[vsharding_annotated_13:%.*]] = mesh.shard [[vreduced]] to [[vsharding_12]] : tensor<i32>
+ %reduced = linalg.reduce ins(%4 : tensor<6x6xi32>) outs(%7 : tensor<i32>) dimensions = [0, 1]
+ (%in: i32, %init: i32) {
+ %9 = arith.addi %in, %init : i32
+ linalg.yield %9 : i32
+ }
+ // CHECK: [[vsharding_14:%.*]] = mesh.sharding @mesh split_axes = {{\[\[}}]] : !mesh.sharding
+ %sharding_0 = mesh.sharding @mesh split_axes = [[]] : !mesh.sharding
+ // CHECK: [[vsharding_annotated_15:%.*]] = mesh.shard [[vsharding_annotated_13]] to [[vsharding_14]] annotate_for_users : tensor<i32>
+ %sharding_annotated_1 = mesh.shard %reduced to %sharding_0 annotate_for_users : tensor<i32>
+ return %sharding_annotated, %4, %sharding_annotated_1 : tensor<6x6xi32>, tensor<6x6xi32>, tensor<i32>
+ }
+}
``````````
</details>
https://github.com/llvm/llvm-project/pull/144079
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