Initial compile support for llama4

torchtitan/experiments/llama4/infra/parallelize.py

@@ -21,11 +21,7 @@
 from torchtitan.config_manager import JobConfig, TORCH_DTYPE_MAP
 from torchtitan.distributed import ParallelDims
 
-from torchtitan.models.llama3.infra.parallelize import (
-    apply_ac,
-    apply_compile,
-    apply_ddp,
-)
+from torchtitan.models.llama3.infra.parallelize import apply_ac, apply_ddp
 from torchtitan.tools.logging import logger
 
 from .expert_parallel import (
@@ -36,6 +32,20 @@
 )
 
 
+def apply_compile(model: nn.Module):
+    """
+    Apply torch.compile to each TransformerBlock, which makes compilation efficient due to
+    repeated structure. Alternatively one can compile the whole model (after applying DP).
+    """
+    torch._dynamo.config.fail_on_recompile_limit_hit = True
+    for layer_id, transformer_block in model.layers.named_children():
+        # NOTE: we allow graph breaks on FSDP hooks for MoE experts, `see set_fullgraph(False)` in moe.py
+        transformer_block = torch.compile(transformer_block, fullgraph=True)
+        model.layers.register_module(layer_id, transformer_block)
+
+    logger.info("Compiling each TransformerBlock with torch.compile")
+
+
 def parallelize_llama(
     model: nn.Module,
     parallel_dims: ParallelDims,

torchtitan/experiments/llama4/model/moe.py

@@ -13,6 +13,75 @@
 from .args import TransformerModelArgs
 
 
+# TODO: keeping this for-loop implementation for comparison
+#       and readability, may remove later
+@expert_parallel
+def _run_experts_for_loop(
+    w1: torch.Tensor,
+    w2: torch.Tensor,
+    w3: torch.Tensor,
+    x: torch.Tensor,
+    num_tokens_per_expert: torch.Tensor | None = None,
+) -> torch.Tensor:
+    if num_tokens_per_expert is not None:
+        # NOTE: this would incur a synchronization between device and host
+        num_tokens_per_expert = num_tokens_per_expert.tolist()
+
+        # side-effect code due to the usage of generate_permute_indices
+        num_padding = x.shape[0] - sum(num_tokens_per_expert)
+
+        # a tuple of tensors indexed by experts
+        # each with shape (tokens_per_expert(varying), dim)
+        x = torch.split(
+            x[: sum(num_tokens_per_expert)],
+            split_size_or_sections=num_tokens_per_expert,
+            dim=0,
+        )
+        out_experts_splits = []
+        for expert_idx, x_expert in enumerate(x):
+            h = F.silu(torch.matmul(x_expert, w1[expert_idx]))
+            h = h * torch.matmul(x_expert, w3[expert_idx])
+            h = torch.matmul(h, w2[expert_idx])
+            # h shape (tokens_per_expert(varying), dim)
+            out_experts_splits.append(h)
+        out = torch.cat(out_experts_splits, dim=0)
+
+        # side-effect code due to the usage of generate_permute_indices
+        out = torch.vstack((out, out.new_zeros((num_padding, out.shape[-1]))))
+    else:
+        # x shape (num_experts, tokens_per_expert, dim)
+        h = F.silu(torch.bmm(x, w1))
+        h = h * torch.bmm(x, w3)
+        # out shape (num_experts, tokens_per_expert, dim)
+        out = torch.bmm(h, w2)
+
+    return out
+
+
+@expert_parallel
+def _run_experts_grouped_mm(
+    w1: torch.Tensor,
+    w2: torch.Tensor,
+    w3: torch.Tensor,
+    x: torch.Tensor,
+    num_tokens_per_expert: torch.Tensor | None = None,
+) -> torch.Tensor:
+    if num_tokens_per_expert is not None:
+        offsets = torch.cumsum(num_tokens_per_expert, dim=0, dtype=torch.int32)
+        # grouped mm between a 2D tensor and a 3D tensor
+        assert x.dim() == 2
+    else:
+        offsets = None
+        # fall back to regular bmm between 3D tensors
+        assert x.dim() == 3
+
+    h = F.silu(torch._grouped_mm(x.bfloat16(), w1.bfloat16(), offs=offsets))
+    h = h * torch._grouped_mm(x.bfloat16(), w3.bfloat16(), offs=offsets)
+    out = torch._grouped_mm(h, w2.bfloat16(), offs=offsets).type_as(x)
+
+    return out
+
+
 class GroupedExperts(nn.Module):
     def __init__(
         self,
@@ -28,89 +97,21 @@ def __init__(
         self.w3 = nn.Parameter(torch.empty(num_experts, dim, hidden_dim))
         self.use_grouped_mm = use_grouped_mm
 
+    @torch._dynamo.set_fullgraph(True)
     def forward(
         self,
         x: torch.Tensor,
         num_tokens_per_expert: torch.Tensor | None = None,
     ) -> torch.Tensor:
         if self.use_grouped_mm:
-            return GroupedExperts._run_experts_grouped_mm(
+            return _run_experts_grouped_mm(
                 self.w1, self.w2, self.w3, x, num_tokens_per_expert
             )
         else:
-            return GroupedExperts._run_experts_for_loop(
+            return _run_experts_for_loop(
                 self.w1, self.w2, self.w3, x, num_tokens_per_expert
             )
 
-    # TODO: keeping this for-loop implementation for comparison
-    #       and readability, may remove later
-    @expert_parallel
-    @staticmethod
-    def _run_experts_for_loop(
-        w1: torch.Tensor,
-        w2: torch.Tensor,
-        w3: torch.Tensor,
-        x: torch.Tensor,
-        num_tokens_per_expert: torch.Tensor | None = None,
-    ) -> torch.Tensor:
-        if num_tokens_per_expert is not None:
-            # NOTE: this would incur a synchronization between device and host
-            num_tokens_per_expert = num_tokens_per_expert.tolist()
-
-            # side-effect code due to the usage of generate_permute_indices
-            num_padding = x.shape[0] - sum(num_tokens_per_expert)
-
-            # a tuple of tensors indexed by experts
-            # each with shape (tokens_per_expert(varying), dim)
-            x = torch.split(
-                x[: sum(num_tokens_per_expert)],
-                split_size_or_sections=num_tokens_per_expert,
-                dim=0,
-            )
-            out_experts_splits = []
-            for expert_idx, x_expert in enumerate(x):
-                h = F.silu(torch.matmul(x_expert, w1[expert_idx]))
-                h = h * torch.matmul(x_expert, w3[expert_idx])
-                h = torch.matmul(h, w2[expert_idx])
-                # h shape (tokens_per_expert(varying), dim)
-                out_experts_splits.append(h)
-            out = torch.cat(out_experts_splits, dim=0)
-
-            # side-effect code due to the usage of generate_permute_indices
-            out = torch.vstack((out, out.new_zeros((num_padding, out.shape[-1]))))
-        else:
-            # x shape (num_experts, tokens_per_expert, dim)
-            h = F.silu(torch.bmm(x, w1))
-            h = h * torch.bmm(x, w3)
-            # out shape (num_experts, tokens_per_expert, dim)
-            out = torch.bmm(h, w2)
-
-        return out
-
-    @expert_parallel
-    @staticmethod
-    def _run_experts_grouped_mm(
-        w1: torch.Tensor,
-        w2: torch.Tensor,
-        w3: torch.Tensor,
-        x: torch.Tensor,
-        num_tokens_per_expert: torch.Tensor | None = None,
-    ) -> torch.Tensor:
-        if num_tokens_per_expert is not None:
-            offsets = torch.cumsum(num_tokens_per_expert, dim=0, dtype=torch.int32)
-            # grouped mm between a 2D tensor and a 3D tensor
-            assert x.dim() == 2
-        else:
-            offsets = None
-            # fall back to regular bmm between 3D tensors
-            assert x.dim() == 3
-
-        h = F.silu(torch._grouped_mm(x.bfloat16(), w1.bfloat16(), offs=offsets))
-        h = h * torch._grouped_mm(x.bfloat16(), w3.bfloat16(), offs=offsets)
-        out = torch._grouped_mm(h, w2.bfloat16(), offs=offsets).type_as(x)
-
-        return out
-
     def init_weights(self, init_std: float):
         nn.init.trunc_normal_(self.w1, mean=0.0, std=0.02)
         nn.init.trunc_normal_(self.w2, mean=0.0, std=init_std)
@@ -297,7 +298,8 @@ def forward(self, x: torch.Tensor) -> torch.Tensor:
         )
 
         # shape (bs*slen*top_k, dim)
-        routed_output = self.experts(routed_input, num_tokens_per_expert)
+        with torch._dynamo.set_fullgraph(False):
+            routed_output = self.experts(routed_input, num_tokens_per_expert)
 
         # shared expert
         if self.shared_expert is not None: