[Kernel] Delegate construction of FusedMoEQuantConfig to FusedMoEMethodBase subclasses (#22537)

Signed-off-by: Bill Nell <bnell@redhat.com>

tests/kernels/quantization/test_int8_kernel.py

@@ -8,7 +8,8 @@ import pytest
 import torch
 
 from vllm.model_executor.layers.activation import SiluAndMul
-from vllm.model_executor.layers.fused_moe import fused_moe
+from vllm.model_executor.layers.fused_moe import fused_experts
+from vllm.model_executor.layers.fused_moe.config import FusedMoEQuantConfig
 from vllm.model_executor.layers.quantization.utils.int8_utils import (
     per_token_quant_int8)
 from vllm.platforms import current_platform
@@ -42,7 +43,8 @@ def native_w8a8_per_token_matmul(A, B, As, Bs, output_dtype=torch.float16):
     return C.reshape(origin_C_shape).to(output_dtype)
 
 
-def torch_w8a8_per_column_moe(a, w1, w2, w1_s, w2_s, score, topk):
+def torch_w8a8_per_column_moe(a, w1, w2, w1_s, w2_s, topk, topk_weight,
+                              topk_ids):
     """This function performs fused moe with per-column int8 quantization
     using native torch."""
 
@@ -57,8 +59,6 @@ def torch_w8a8_per_column_moe(a, w1, w2, w1_s, w2_s, score, topk):
     out = torch.zeros(B * topk, w2.shape[1], dtype=a.dtype, device=a.device)
 
     # Calculate routing
-    score = torch.softmax(score, dim=-1, dtype=torch.float32)
-    topk_weight, topk_ids = torch.topk(score, topk)
     topk_weight = topk_weight.view(-1)
     topk_ids = topk_ids.view(-1)
     # Process each expert
@@ -127,20 +127,27 @@ def test_w8a8_fp8_fused_moe(M, N, K, E, topk, dtype, seed):
     w1_s = torch.rand(E, 2 * N, device=w1_fp32.device) * factor_for_scale
     w2_s = torch.rand(E, K, device=w2_fp32.device) * factor_for_scale
     score = torch.randn((M, E), dtype=dtype)
+    score = torch.softmax(score, dim=-1, dtype=torch.float32)
+    topk_weights, topk_ids = torch.topk(score, topk)
 
-    ref_out = torch_w8a8_per_column_moe(a, w1, w2, w1_s, w2_s, score, topk)
-    out = fused_moe(
+    ref_out = torch_w8a8_per_column_moe(a, w1, w2, w1_s, w2_s, topk,
+                                        topk_weights, topk_ids)
+
+    quant_config = FusedMoEQuantConfig.make(
+        torch.int8,
+        per_act_token_quant=True,
+        block_shape=None,
+        w1_scale=w1_s,
+        w2_scale=w2_s,
+    )
+
+    out = fused_experts(
         a,
         w1,
         w2,
-        score,
-        topk,
-        renormalize=False,
-        use_int8_w8a8=True,  # Using int8-w8a8
-        per_channel_quant=True,
-        w1_scale=w1_s,
-        w2_scale=w2_s,
-        block_shape=None,  # Not using block quantization
+        topk_weights,
+        topk_ids,
+        quant_config=quant_config,
     )
 
     # Check results