[Misc] Fixes and Optimizations for DeepEP + DeepGEMM combination. (#19298)

Signed-off-by: Varun <vsundarr@redhat.com>
Co-authored-by: Varun <vsundarr@redhat.com>

Author: varun-sundar-rabindranath

tests/kernels/moe/test_pplx_moe.py

@@ -274,7 +274,7 @@ def pplx_prepare_finalize(pgi: ProcessGroupInfo, dp_size: int, a: torch.Tensor,
     chunk_topk_weight = chunk_by_rank(topk_weight, rank, world_size).to(device)
     chunk_topk_ids = chunk_by_rank(topk_ids, rank, world_size).to(device)
 
-    b_a, b_a_scale, expert_num_tokens = prepare_finalize.prepare(
+    b_a, b_a_scale, expert_num_tokens, _, _ = prepare_finalize.prepare(
         a_chunk,
         None,
         None,

vllm/distributed/device_communicators/all2all.py

@@ -233,16 +233,11 @@ def _make_all2all_kwargs(
         # Defaults for internode and intranode are taken from DeepEP tests.
         num_nvl_bytes = 1024 * 1024 * 1024
         num_qps_per_rank = num_local_experts
-        num_rdma_bytes = None
-
-        if self.internode:
-            num_rdma_bytes = 1024 * 1024 * 1024
-        else:
-            num_rdma_bytes = deep_ep.Buffer.get_low_latency_rdma_size_hint(
-                num_max_dispatch_tokens_per_rank=max_num_tokens_per_dp_rank,
-                hidden=token_hidden_size,
-                num_ranks=num_ep_ranks,
-                num_experts=num_global_experts)
+        num_rdma_bytes = deep_ep.Buffer.get_low_latency_rdma_size_hint(
+            num_max_dispatch_tokens_per_rank=max_num_tokens_per_dp_rank,
+            hidden=token_hidden_size,
+            num_ranks=num_ep_ranks,
+            num_experts=num_global_experts)
 
         assert num_rdma_bytes is not None
         return dict(group=self.cpu_group,

vllm/envs.py

@@ -110,6 +110,7 @@
     VLLM_DP_SIZE: int = 1
     VLLM_DP_MASTER_IP: str = ""
     VLLM_DP_MASTER_PORT: int = 0
+    VLLM_RANDOMIZE_DP_DUMMY_INPUTS: bool = False
     VLLM_MARLIN_USE_ATOMIC_ADD: bool = False
     VLLM_V0_USE_OUTLINES_CACHE: bool = False
     VLLM_TPU_BUCKET_PADDING_GAP: int = 0
@@ -761,6 +762,10 @@ def get_vllm_port() -> Optional[int]:
     "VLLM_DP_MASTER_PORT":
     lambda: int(os.getenv("VLLM_DP_MASTER_PORT", "0")),
 
+    # Randomize inputs during dummy runs when using Data Parallel
+    "VLLM_RANDOMIZE_DP_DUMMY_INPUTS":
+    lambda: os.environ.get("VLLM_RANDOMIZE_DP_DUMMY_INPUTS", "0") == "1",
+
     # Whether to use S3 path for model loading in CI via RunAI Streamer
     "VLLM_CI_USE_S3":
     lambda: os.environ.get("VLLM_CI_USE_S3", "0") == "1",

vllm/model_executor/layers/fused_moe/deep_gemm_moe.py

@@ -80,11 +80,13 @@ def workspace_shapes(
         topk: int,
         num_experts: int,
     ) -> tuple[int, int, torch.dtype]:
+
         block_m = self.block_shape[0]
         M_sum = (M * topk) + num_experts * (block_m - 1)
         M_sum = round_up(M_sum, block_m)
         workspace1 = M_sum * max(N * 2, K)
-        workspace2 = M_sum * N
+        workspace2 = M_sum * max(N, K)
+
         return (workspace1, workspace2, a.dtype)
 
     def apply(
@@ -135,26 +137,31 @@ def apply(
 
         # Note: M_sum is different than the pre-permuted shape of a1q.
         M_sum = a1q.size(0)
-        workspace1 = _resize_cache(workspace13, (M_sum, N))
-        workspace2 = _resize_cache(workspace2, (M_sum, N // 2))
-        workspace3 = _resize_cache(workspace13, (M_sum, K))
+
+        mm1_out = _resize_cache(workspace13, (M_sum, N))
+        act_out = _resize_cache(workspace2, (M_sum, N // 2))
+        quant_out = _resize_cache(workspace13.view(dtype=torch.float8_e4m3fn),
+                                  (M_sum, N // 2))
+        mm2_out = _resize_cache(workspace2, (M_sum, K))
+        out = _resize_cache(workspace13, (inv_perm.size(0), K))
 
         dg.m_grouped_gemm_fp8_fp8_bf16_nt_contiguous(
-            (a1q, a1q_scale), (w1, w1_scale), workspace1, expert_ids)
+            (a1q, a1q_scale), (w1, w1_scale), mm1_out, expert_ids)
 
-        self.activation(activation, workspace2, workspace1.view(-1, N))
+        self.activation(activation, act_out, mm1_out.view(-1, N))
 
         a2q_scale: Optional[torch.Tensor] = None
-        a2q, a2q_scale = per_token_group_quant_fp8(workspace2,
+        a2q, a2q_scale = per_token_group_quant_fp8(act_out,
                                                    self.block_shape[1],
-                                                   column_major_scales=True)
+                                                   column_major_scales=True,
+                                                   out_q=quant_out)
 
         dg.m_grouped_gemm_fp8_fp8_bf16_nt_contiguous(
-            (a2q, a2q_scale), (w2, w2_scale), workspace3, expert_ids)
+            (a2q, a2q_scale), (w2, w2_scale), mm2_out, expert_ids)
 
-        workspace3 = workspace3[inv_perm, ...]
+        torch.index_select(mm2_out, 0, inv_perm, out=out)
 
-        return workspace3
+        return out
 
 
 def deep_gemm_moe_fp8(

vllm/model_executor/layers/fused_moe/deepep_ht_prepare_finalize.py

@@ -5,6 +5,7 @@
 import torch
 
 import vllm.model_executor.layers.fused_moe.modular_kernel as mk
+from vllm import _custom_ops as ops
 from vllm.model_executor.layers.fused_moe.utils import (
     moe_kernel_quantize_input)
 
@@ -193,20 +194,23 @@ def _apply_weights_and_reduce(self, num_tokens: int,
                                   apply_router_weight_on_input: bool,
                                   output_dtype: torch.dtype):
 
+        hidden_dim = fused_expert_output.size(-1)
         if fused_expert_output.ndim == 2:
-            hidden_dim = fused_expert_output.size(-1)
             fused_expert_output = fused_expert_output.view(
                 num_tokens, -1, hidden_dim)
 
         if not apply_router_weight_on_input:
             # The DeepEP combine kernels don't do the topk weight
             # multiplication. We multiply the weights locally.
-            fused_expert_output = fused_expert_output.to(torch.float32)
-            fused_expert_output = fused_expert_output * topk_weights.view(
-                fused_expert_output.size(0), -1, 1)
-            fused_expert_output = fused_expert_output.to(output_dtype)
+            m_x_topk = fused_expert_output.size(0)
+            fused_expert_output.mul_(topk_weights.view(m_x_topk, -1, 1))
 
-        return fused_expert_output.sum(dim=1).to(output_dtype)
+        out = torch.empty((num_tokens, hidden_dim),
+                          device=fused_expert_output.device,
+                          dtype=output_dtype)
+        ops.moe_sum(fused_expert_output, out)
+
+        return out
 
     def finalize(self, output: torch.Tensor, fused_expert_output: torch.Tensor,
                  topk_weights: torch.Tensor, topk_ids: torch.Tensor,

vllm/model_executor/layers/fused_moe/moe_permute_unpermute.py

@@ -18,7 +18,7 @@ def _moe_permute(
     expert_map: Optional[torch.Tensor],
     block_m: int,
 ) -> tuple[torch.Tensor, Optional[torch.Tensor], torch.Tensor, torch.Tensor,
-           Optional[torch.Tensor]]:
+           torch.Tensor]:
     """
     Determine the sorted_token_ids, expert_ids for the given problem size.
     Permute the hidden states and scales according to `sorted_token_ids`.

vllm/model_executor/layers/quantization/utils/fp8_utils.py

@@ -234,8 +234,13 @@ def _per_token_group_quant_fp8(
     row = g_id // groups_per_row
     row_g_id = g_id % groups_per_row
 
-    y_ptr += (row * y_row_stride) + (row_g_id * group_size)
-    y_q_ptr += g_id * group_size
+    # Ensure offset calculations use int64 to prevent overflow
+    y_ptr_offset = (row.to(tl.int64) * y_row_stride) + (row_g_id.to(tl.int64) *
+                                                        group_size)
+    y_ptr += y_ptr_offset
+
+    y_q_ptr_offset = g_id.to(tl.int64) * group_size
+    y_q_ptr += y_q_ptr_offset
     y_s_ptr += g_id
 
     cols = tl.arange(0, BLOCK)  # N <= BLOCK
@@ -282,15 +287,23 @@ def _per_token_group_quant_fp8_colmajor(
     row = g_id // groups_per_row
     row_g_id = g_id % groups_per_row
 
-    y_ptr += (row * y_row_stride) + (row_g_id * group_size)
-    y_q_ptr += g_id * group_size
+    # Ensure offset calculations use int64 to prevent overflow
+    y_ptr_offset = (row.to(tl.int64) * y_row_stride) + (row_g_id.to(tl.int64) *
+                                                        group_size)
+    y_ptr += y_ptr_offset
+
+    y_q_ptr_offset = g_id.to(tl.int64) * group_size
+    y_q_ptr += y_q_ptr_offset
 
     # Convert g_id the flattened block coordinate to 2D so we can index
     # into the output y_scales matrix
     blocks_per_row = y_num_columns // group_size
     scale_col = g_id % blocks_per_row
     scale_row = g_id // blocks_per_row
-    y_s_ptr += scale_col * y_s_col_stride + scale_row
+    # Ensure offset calculation uses int64 for y_s_ptr
+    y_s_ptr_offset = (scale_col.to(tl.int64) * y_s_col_stride) + scale_row.to(
+        tl.int64)
+    y_s_ptr += y_s_ptr_offset
 
     cols = tl.arange(0, BLOCK)  # group_size <= BLOCK
     mask = cols < group_size
@@ -311,6 +324,7 @@ def per_token_group_quant_fp8(
     eps: float = 1e-10,
     dtype: Optional[torch.dtype] = None,
     column_major_scales: bool = False,
+    out_q: Optional[torch.Tensor] = None,
 ) -> tuple[torch.Tensor, torch.Tensor]:
     """Function to perform per-token-group quantization on an input tensor `x`.
     It converts the tensor values into signed float8 values and returns the
@@ -321,6 +335,8 @@ def per_token_group_quant_fp8(
         eps: The minimum to avoid dividing zero.
         dtype: The dype of output tensor. Note that only `torch.float8_e4m3fn`
         is supported for now.
+        column_major_scales: Outputs scales in column major.
+        out_q: Optional output tensor. If not provided, function will create.
     Returns:
         tuple[torch.Tensor, torch.Tensor]: The quantized tensor and the
         scaling factor for quantization.
@@ -335,7 +351,11 @@ def per_token_group_quant_fp8(
     fp8_min = finfo.min
     fp8_max = finfo.max
 
-    x_q = torch.empty_like(x, device=x.device, dtype=dtype)
+    assert out_q is None or out_q.shape == x.shape
+    x_q = out_q
+    if x_q is None:
+        x_q = torch.empty_like(x, device=x.device, dtype=dtype)
+
     M = x.numel() // group_size
     N = group_size
     if column_major_scales:

vllm/v1/worker/gpu_model_runner.py

@@ -5,13 +5,15 @@
 import gc
 import time
 import weakref
+from contextlib import contextmanager
 from typing import TYPE_CHECKING, Any, Optional, Union
 
 import numpy as np
 import torch
 import torch.distributed
 import torch.nn as nn
 
+import vllm.envs as envs
 from vllm.attention import AttentionType, get_attn_backend
 from vllm.attention.backends.abstract import (AttentionBackend,
                                               AttentionMetadataBuilder)
@@ -1727,6 +1729,35 @@ def _get_prompt_logprobs_dict(
 
         return prompt_logprobs_dict
 
+    @contextmanager
+    def maybe_randomize_inputs(self, input_ids: torch.Tensor):
+        """
+        Randomize input_ids if VLLM_RANDOMIZE_DP_DUMMY_INPUTS is set.
+        This is to help balance expert-selection
+         - during profile_run
+         - during DP rank dummy run 
+        """
+        dp_size = self.vllm_config.parallel_config.data_parallel_size
+        randomize_inputs = envs.VLLM_RANDOMIZE_DP_DUMMY_INPUTS and dp_size > 1
+        if not randomize_inputs:
+            yield
+        else:
+            import functools
+
+            @functools.cache
+            def rand_input_ids() -> torch.Tensor:
+                return torch.randint_like(
+                    self.input_ids,
+                    low=0,
+                    high=self.model_config.get_vocab_size(),
+                    dtype=input_ids.dtype)
+
+            logger.debug("Randomizing dummy data for DP Rank")
+            input_ids.copy_(rand_input_ids()[:input_ids.size(0)],
+                            non_blocking=True)
+            yield
+            input_ids.fill_(0)
+
     @torch.inference_mode()
     def _dummy_run(
         self,
@@ -1807,7 +1838,7 @@ def _dummy_run(
                 intermediate_tensors = self.sync_and_slice_intermediate_tensors(
                     num_tokens, None, False)
 
-            with set_forward_context(
+            with self.maybe_randomize_inputs(input_ids), set_forward_context(
                     attn_metadata,
                     self.vllm_config,
                     num_tokens=num_tokens,