[Bugfix] Fix Maverick correctness by filling zero to cache space in cutlass_moe (#20167)

Signed-off-by: Ming Yang <yming@meta.com>

tests/kernels/moe/test_cutlass_moe.py

 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 import dataclasses
+from math import prod
 from typing import Optional
 
 import pytest
@@ -8,9 +9,12 @@ import torch
 
 from vllm import _custom_ops as ops
 from vllm.config import ParallelConfig, VllmConfig, set_current_vllm_config
-from vllm.model_executor.layers.fused_moe.cutlass_moe import cutlass_moe_fp8
+from vllm.model_executor.layers.fused_moe.cutlass_moe import (
+    cutlass_moe_fp8, run_cutlass_moe_fp8)
 from vllm.model_executor.layers.fused_moe.fused_moe import (fused_experts,
                                                             fused_topk)
+from vllm.model_executor.layers.fused_moe.utils import (
+    moe_kernel_quantize_input)
 from vllm.platforms import current_platform
 
 NUM_EXPERTS = [40, 64]
@@ -236,6 +240,7 @@ def test_cutlass_moe_8_bit_no_graph(
     per_act_token: bool,
     per_out_ch: bool,
     monkeypatch,
+    ep_size: Optional[int] = None,
 ):
     current_platform.seed_everything(7)
     monkeypatch.setenv("VLLM_FUSED_MOE_CHUNK_SIZE", "8192")
@@ -254,7 +259,13 @@ def test_cutlass_moe_8_bit_no_graph(
         triton_output = fused_experts(mt.a_d, mt.w1_d, mt.w2_d, topk_weights,
                                       topk_ids)
 
-        cutlass_output = run_8_bit(mt, topk_weights, topk_ids, per_act_token)
+        if ep_size is not None:
+            assert e % ep_size == 0, "Cannot distribute experts evenly"
+            number_local_experts = e // ep_size
+        else:
+            number_local_experts = None
+        cutlass_output = run_8_bit(mt, topk_weights, topk_ids, per_act_token,
+                                   number_local_experts)
 
         # Note 5.5 only needed for larger problem sizes, 5 works ok for
         # the rest.
@@ -340,9 +351,62 @@ def test_cutlass_moe_8_bit_EP(
     per_out_channel: bool,
     ep_size: int,
     monkeypatch,
+):
+    test_cutlass_moe_8_bit_no_graph(m, n, k, e, topk, per_act_token,
+                                    per_out_channel, monkeypatch, ep_size)
+
+
+LARGE_MNK_FACTORS = [
+    (1, 8192, 5120, 31),
+    (32768, 1024, 1024, 16),
+    (65536, 512, 1024, 16),
+]
+
+
+@pytest.mark.parametrize("m,n,k,topk", LARGE_MNK_FACTORS)
+@pytest.mark.parametrize("e", [128])
+@pytest.mark.parametrize("per_act_token", [False])
+@pytest.mark.parametrize("per_out_channel", [True])
+@pytest.mark.parametrize("ep_size", [8])
+@pytest.mark.skipif(
+    (lambda x: x is None or not ops.cutlass_group_gemm_supported(x.to_int()))(
+        current_platform.get_device_capability()),
+    reason="Grouped gemm is not supported on this GPU type.")
+def test_cutlass_moe_8_bit_EP_large(
+    m: int,
+    n: int,
+    k: int,
+    e: int,
+    topk: int,
+    per_act_token: bool,
+    per_out_channel: bool,
+    ep_size: int,
+    monkeypatch,
+):
+    test_cutlass_moe_8_bit_no_graph(m, n, k, e, topk, per_act_token,
+                                    per_out_channel, monkeypatch, ep_size)
+
+
+@pytest.mark.parametrize("m,n,k,topk", [(1, 8192, 5120, 31)])
+@pytest.mark.parametrize("e", [128])
+@pytest.mark.parametrize("per_act_token", [False])
+@pytest.mark.parametrize("per_out_channel", [True])
+@pytest.mark.parametrize("ep_size", [8])
+@pytest.mark.skipif(
+    (lambda x: x is None or not ops.cutlass_group_gemm_supported(x.to_int()))(
+        current_platform.get_device_capability()),
+    reason="Grouped gemm is not supported on this GPU type.")
+def test_run_cutlass_moe_fp8(
+    m: int,
+    n: int,
+    k: int,
+    e: int,
+    topk: int,
+    per_act_token: bool,
+    per_out_channel: bool,
+    ep_size: int,
 ):
     current_platform.seed_everything(7)
-    monkeypatch.setenv("VLLM_FUSED_MOE_CHUNK_SIZE", "8192")
     with set_current_vllm_config(vllm_config):
         mt = MOETensors8Bit.make_moe_tensors_8bit(m, k, n, e, per_act_token,
                                                   per_out_channel)
@@ -352,20 +416,53 @@ def test_cutlass_moe_8_bit_EP(
                                                score,
                                                topk,
                                                renormalize=False)
-
-        # Note that we are using the dequantized versions of the tensors.
-        # Using a, w1 and w2 directly results in minor output differences.
-        triton_output = fused_experts(mt.a_d, mt.w1_d, mt.w2_d, topk_weights,
-                                      topk_ids)
-
-        assert e % ep_size == 0, "Cannot distribute experts evenly"
-        cutlass_output = run_8_bit(mt,
-                                   topk_weights,
-                                   topk_ids,
-                                   per_act_token,
-                                   num_local_experts=e // ep_size)
-
-        torch.testing.assert_close(triton_output,
-                                   cutlass_output,
-                                   atol=5e-2,
-                                   rtol=1e-2)
+        # we want to make sure there is at least one token that's generated in
+        # this expert shard and at least one token that's NOT generated in this
+        # expert shard
+        topk_ids[0][0] = -1
+        topk_ids[0][1] = 1
+
+        workspace13_shape = (m * topk, max(2 * n, k))
+        workspace2_shape = (m * topk, n)
+        output_shape = (m * topk, k)
+
+        workspace13 = torch.empty(prod(workspace13_shape),
+                                  device="cuda",
+                                  dtype=mt.a.dtype)
+        workspace2 = torch.empty(prod(workspace2_shape),
+                                 device="cuda",
+                                 dtype=mt.a.dtype)
+
+        num_local_experts = e // ep_size
+        start, end = 0, num_local_experts
+        expert_map = [-1] * e
+        expert_map[start:end] = list(range(num_local_experts))
+        expert_map = torch.tensor(expert_map, dtype=torch.int32, device="cuda")
+
+        activation = lambda o, i: torch.ops._C.silu_and_mul(o, i)
+        a1q, a1q_scale = moe_kernel_quantize_input(mt.a, mt.a_scale,
+                                                   torch.float8_e4m3fn,
+                                                   per_act_token)
+        global_num_experts = -1 if mt.w1_q is None else mt.w1_q.size(0)
+        func = lambda output: run_cutlass_moe_fp8(
+            output, a1q, mt.w1_q, mt.w2_q, topk_ids, activation,
+            global_num_experts, expert_map, mt.w1_scale, mt.w2_scale,
+            a1q_scale, None, workspace13, workspace2, None, mt.a.dtype,
+            per_act_token, per_out_channel, False)
+
+        workspace13.random_()
+        output_random_workspace = torch.empty(output_shape,
+                                              device="cuda",
+                                              dtype=mt.a.dtype)
+        func(output_random_workspace)
+
+        workspace13.fill_(0)
+        output_zero_workspace = torch.zeros(output_shape,
+                                            device="cuda",
+                                            dtype=mt.a.dtype)
+        func(output_zero_workspace)
+
+        torch.testing.assert_close(output_random_workspace,
+                                   output_zero_workspace,
+                                   atol=5e-3,
+                                   rtol=1e-3)

vllm/model_executor/layers/fused_moe/cutlass_moe.py

@@ -180,7 +180,11 @@ def run_cutlass_moe_fp8(
         c2 = _resize_cache(workspace2, (M * topk, N))
         c3 = _resize_cache(workspace13, (M * topk, K))
 
-    c1.fill_(0)
+    if not per_act_token and (expert_map is not None or use_batched_format):
+        # this is necessary to avoid imprecise scale calculation caused by
+        # random data in the unused workspace. The workspace is unused when
+        # this rank handles only partial tokens, or when it is batched .
+        c1.fill_(0)
 
     ops.cutlass_moe_mm(c1, a1q, w1, a1q_scale, w1_scale, expert_offsets,
                        problem_sizes1, ab_strides1, ab_strides1, c_strides1,
@@ -303,7 +307,7 @@ class CutlassExpertsFp8(mk.FusedMoEPermuteExpertsUnpermute):
     ):
         assert w1_zp is None, "w1_zp is not supported in CUTLASS MoE"
         assert w2_zp is None, "w2_zp is not supported in CUTLASS MoE"
-        activation_callable = lambda i, o: self.activation(activation, i, o)
+        activation_callable = lambda o, i: self.activation(activation, o, i)
         in_dtype = hidden_states.dtype
         run_cutlass_moe_fp8(
             output, hidden_states, w1, w2, topk_ids, activation_callable,