[Kernel] Enable 8-bit weights in Fused Marlin MoE (#8032)

Co-authored-by: Dipika <dipikasikka1@gmail.com>

csrc/moe/marlin_moe_ops.h

@@ -2,11 +2,14 @@
 
 #include <torch/all.h>
 
+#include "core/scalar_type.hpp"
+
 torch::Tensor marlin_gemm_moe(
     const torch::Tensor& a, const torch::Tensor& b_q_weights,
     const torch::Tensor& sorted_ids, const torch::Tensor& topk_weights,
     const torch::Tensor& topk_ids, const torch::Tensor& b_scales,
     const torch::Tensor& g_idx, const torch::Tensor& perm,
-    torch::Tensor& workspace, int64_t size_m, int64_t size_n, int64_t size_k,
-    bool is_k_full, int64_t num_experts, int64_t topk, int64_t moe_block_size,
+    torch::Tensor& workspace, vllm::ScalarTypeTorchPtr const& b_q_type,
+    int64_t size_m, int64_t size_n, int64_t size_k, bool is_k_full,
+    int64_t num_experts, int64_t topk, int64_t moe_block_size,
     bool replicate_input, bool apply_weights);

csrc/moe/torch_bindings.cpp

@@ -13,9 +13,11 @@ TORCH_LIBRARY_EXPAND(TORCH_EXTENSION_NAME, m) {
   m.def(
       "marlin_gemm_moe(Tensor! a, Tensor! b_q_weights, Tensor! sorted_ids, "
       "Tensor! topk_weights, Tensor! topk_ids, Tensor! b_scales, Tensor! "
-      "g_idx, Tensor! perm, Tensor! workspace, int size_m, int size_n, int "
-      "size_k, bool is_k_full, int num_experts, int topk, int moe_block_size, "
-      "bool replicate_input, bool apply_weights) -> Tensor");
+      "g_idx, Tensor! perm, Tensor! workspace, "
+      "__torch__.torch.classes._core_C.ScalarType b_q_type, int size_m, "
+      "int size_n, int size_k, bool is_k_full, int num_experts, int topk, "
+      "int moe_block_size, bool replicate_input, bool apply_weights)"
+      " -> Tensor");
   m.impl("marlin_gemm_moe", torch::kCUDA, &marlin_gemm_moe);
 #endif
 }

tests/kernels/test_moe.py

@@ -140,6 +140,7 @@ def compute_max_diff(output, output_ref):
 @pytest.mark.parametrize("topk", [2, 6])
 @pytest.mark.parametrize("group_size", [-1, 32, 64, 128])
 @pytest.mark.parametrize("act_order", [True, False])
+@pytest.mark.parametrize("num_bits", [4, 8])
 def test_fused_marlin_moe(
     m: int,
     n: int,
@@ -148,6 +149,7 @@ def test_fused_marlin_moe(
     topk: int,
     group_size: int,
     act_order: bool,
+    num_bits: int,
 ):
     torch.manual_seed(7)
 
@@ -161,13 +163,12 @@ def test_fused_marlin_moe(
         if group_size in (k, n):
             return
 
-    quant_type = scalar_types.uint4b8
+    quant_type = (scalar_types.uint4b8
+                  if num_bits == 4 else scalar_types.uint8b128)
     dtype = torch.float16
     a = torch.randn((m, k), device="cuda", dtype=dtype) / 10
     w1 = torch.randn((e, 2 * n, k), device="cuda", dtype=dtype) / 10
     w2 = torch.randn((e, k, n), device="cuda", dtype=dtype) / 10
-    for i in range(w2.shape[0]):
-        w2[0] = torch.eye(k, n, device="cuda", dtype=dtype)
 
     w_ref1_l = []
     qweight1_l = []
@@ -240,6 +241,7 @@ def test_fused_marlin_moe(
         topk_ids,
         w1_scale=scales1,
         w2_scale=scales2,
+        num_bits=num_bits,
     )
 
     assert compute_max_diff(marlin_output, triton_output) < 4e-2
@@ -254,7 +256,8 @@ def test_fused_marlin_moe(
 @pytest.mark.parametrize("topk", [2, 6])
 @pytest.mark.parametrize("group_size", [-1, 32, 64, 128])
 @pytest.mark.parametrize("act_order", [True, False])
-def test_marlin_moe_mmm(
+@pytest.mark.parametrize("num_bits", [4, 8])
+def test_single_marlin_moe_multiply(
     m: int,
     n: int,
     k: int,
@@ -262,6 +265,7 @@ def test_marlin_moe_mmm(
     topk: int,
     group_size: int,
     act_order: bool,
+    num_bits: int,
 ):
     if topk > e:
         return
@@ -273,7 +277,8 @@ def test_marlin_moe_mmm(
         if group_size == k:
             return
 
-    quant_type = scalar_types.uint4b8
+    quant_type = (scalar_types.uint4b8
+                  if num_bits == 4 else scalar_types.uint8b128)
     dtype = torch.float16
     a = torch.randn((m, k), device="cuda", dtype=dtype) / 10
     w = torch.randn((e, n, k), device="cuda", dtype=dtype) / 10
@@ -308,7 +313,8 @@ def test_marlin_moe_mmm(
                                       g_idx,
                                       sort_indices,
                                       topk,
-                                      renormalize=False)
+                                      renormalize=False,
+                                      num_bits=num_bits)
     torch_output = torch_moe_single(a, w_ref.transpose(1, 2), score, topk)
 
     assert compute_max_diff(marlin_output, torch_output) < 1e-2

tests/weight_loading/models-large.txt

 compressed-tensors, nm-testing/Mixtral-8x7B-Instruct-v0.1-W4A16-quantized, main
 compressed-tensors, nm-testing/Mixtral-8x7B-Instruct-v0.1-W4A16-channel-quantized, main
-gptq_marlin, TheBloke/Mixtral-8x7B-v0.1-GPTQ, main
+compressed-tensors, nm-testing/Mixtral-8x7B-Instruct-v0.1-W8A16-quantized, main
\ No newline at end of file
+gptq_marlin, TheBloke/Mixtral-8x7B-v0.1-GPTQ, main

vllm/_custom_ops.py

@@ -559,7 +559,7 @@ def gptq_marlin_moe_repack(b_q_weight: torch.Tensor, perm: torch.Tensor,
                            num_bits: int) -> torch.Tensor:
     num_experts = b_q_weight.shape[0]
     assert size_k % 16 == 0
-    output = torch.empty((num_experts, size_k // 16, size_n * 2),
+    output = torch.empty((num_experts, size_k // 16, size_n * (num_bits // 2)),
                          device=b_q_weight.device,
                          dtype=b_q_weight.dtype)
     for e in range(num_experts):

vllm/model_executor/layers/fused_moe/fused_marlin_moe.py

@@ -7,18 +7,21 @@ import torch
 from vllm import _custom_ops as ops
 from vllm.model_executor.layers.fused_moe.fused_moe import (
     fused_topk, moe_align_block_size, try_get_optimal_moe_config)
+from vllm.scalar_type import scalar_types
 
 
 def single_marlin_moe(
-        hidden_states: torch.Tensor,
-        w: torch.Tensor,
-        scales: torch.Tensor,
-        gating_output: torch.Tensor,
-        g_idx: torch.Tensor,
-        perm: torch.Tensor,
-        topk: int,
-        renormalize: bool,
-        override_config: Optional[Dict[str, Any]] = None) -> torch.Tensor:
+    hidden_states: torch.Tensor,
+    w: torch.Tensor,
+    scales: torch.Tensor,
+    gating_output: torch.Tensor,
+    g_idx: torch.Tensor,
+    perm: torch.Tensor,
+    topk: int,
+    renormalize: bool,
+    override_config: Optional[Dict[str, Any]] = None,
+    num_bits: int = 8,
+) -> torch.Tensor:
     """
     This function computes the multiplication of hidden_states with expert
     weights used in Marlin MoE, using weights w and top-k gating mechanism.
@@ -36,6 +39,7 @@ def single_marlin_moe(
     - renormalize (bool): If True, renormalize the top-k weights to sum to 1.
     - override_config (Optional[Dict[str, Any]]): Optional override
         for the kernel configuration.
+    - num_bits (bool): The number of bits in expert weights quantization.
 
     Returns:
     - torch.Tensor: The output tensor after applying the MoE layer.
@@ -48,10 +52,11 @@ def single_marlin_moe(
     assert hidden_states.is_contiguous(), "Hidden_states must be contiguous"
     assert w.is_contiguous(), "Expert weights must be contiguous"
     assert hidden_states.dtype == torch.float16
+    assert num_bits in [4, 8]
 
     M, K = hidden_states.shape
     E = w.shape[0]
-    N = w.shape[2] // 2
+    N = w.shape[2] // (num_bits // 2)
 
     topk_weights, topk_ids = fused_topk(hidden_states, gating_output, topk,
                                         renormalize)
@@ -76,10 +81,13 @@ def single_marlin_moe(
                             device="cuda",
                             requires_grad=False)
 
+    scalar_type = (scalar_types.uint4b8
+                   if num_bits == 4 else scalar_types.uint8b128)
+
     intermediate_cache = torch.ops._moe_C.marlin_gemm_moe(
         hidden_states, w, sorted_token_ids, topk_weights, topk_ids, scales,
-        g_idx, perm, workspace, M, N, K, True, E, topk, block_size_m, True,
-        False)
+        g_idx, perm, workspace, scalar_type, M, N, K, True, E, topk,
+        block_size_m, True, False)
 
     return torch.sum(intermediate_cache.view(*intermediate_cache.shape), dim=1)
 
@@ -98,6 +106,7 @@ def fused_marlin_moe(
     override_config: Optional[Dict[str, Any]] = None,
     w1_scale: Optional[torch.Tensor] = None,
     w2_scale: Optional[torch.Tensor] = None,
+    num_bits: int = 8,
 ) -> torch.Tensor:
     """
     This function computes a Mixture of Experts (MoE) layer using two sets of
@@ -122,6 +131,7 @@ def fused_marlin_moe(
         w1.
     - w2_scale (Optional[torch.Tensor]): Optional scale to be used for
         w2.
+    - num_bits (bool): The number of bits in expert weights quantization.
 
     Returns:
     - torch.Tensor: The output tensor after applying the MoE layer.
@@ -131,13 +141,14 @@ def fused_marlin_moe(
         0], "Number of tokens mismatch"
     assert hidden_states.shape[
         1] == w1.shape[1] * 16, "Hidden size mismatch w1"
-    assert hidden_states.shape[
-        1] == w2.shape[2] // 2, "Hidden size mismatch w2"
+    assert hidden_states.shape[1] == w2.shape[2] // (
+        num_bits // 2), "Hidden size mismatch w2"
     assert gating_output.shape[1] == w1.shape[0], "Number of experts mismatch"
     assert hidden_states.is_contiguous(), "Hidden_states must be contiguous"
     assert w1.is_contiguous(), "Expert weights1 must be contiguous"
     assert w2.is_contiguous(), "Expert weights2 must be contiguous"
     assert hidden_states.dtype == torch.float16
+    assert num_bits in [4, 8]
 
     M, K = hidden_states.shape
     E = w1.shape[0]
@@ -165,6 +176,9 @@ def fused_marlin_moe(
                             device="cuda",
                             requires_grad=False)
 
+    scalar_type = (scalar_types.uint4b8
+                   if num_bits == 4 else scalar_types.uint8b128)
+
     intermediate_cache2 = torch.empty(
         (M * topk_ids.shape[1], N),
         device=hidden_states.device,
@@ -181,6 +195,7 @@ def fused_marlin_moe(
         g_idx1,
         perm1,
         workspace,
+        scalar_type,
         M,
         2 * N,
         K,
@@ -204,6 +219,7 @@ def fused_marlin_moe(
         g_idx2,
         perm2,
         workspace,
+        scalar_type,
         M,
         K,
         N,

vllm/model_executor/layers/fused_moe/fused_moe.py

@@ -445,7 +445,7 @@ def grouped_topk(hidden_states: torch.Tensor,
     if renormalize:
         topk_weights = topk_weights / topk_weights.sum(dim=-1, keepdim=True)
 
-    return topk_weights, topk_ids.to(torch.int32)
+    return topk_weights.to(torch.float32), topk_ids.to(torch.int32)
 
 
 def get_config_dtype_str(dtype: torch.dtype,

vllm/model_executor/layers/quantization/compressed_tensors/compressed_tensors_moe.py

@@ -6,6 +6,8 @@ import torch
 
 from vllm import _custom_ops as ops
 from vllm.model_executor.layers.fused_moe import FusedMoE, FusedMoEMethodBase
+from vllm.model_executor.layers.quantization.compressed_tensors.schemes import (
+    WNA16_SUPPORTED_BITS)
 from vllm.model_executor.layers.quantization.compressed_tensors.utils import (
     CompressionFormat)
 from vllm.model_executor.utils import set_weight_attrs
@@ -38,10 +40,11 @@ class CompressedTensorsMoEMethod(FusedMoEMethodBase):
 
         if not (self.quant_config.quant_format
                 == CompressionFormat.pack_quantized.value
-                and self.num_bits == 4):
+                and self.num_bits in WNA16_SUPPORTED_BITS):
             raise ValueError("For Fused MoE layers, only ",
                              f"{CompressionFormat.pack_quantized.value} ",
-                             "is supported for 4 bits")
+                             "is supported for the following bits: ",
+                             f"{WNA16_SUPPORTED_BITS}")
 
     def create_weights(self, layer: torch.nn.Module, num_experts: int,
                        hidden_size: int, intermediate_size: int,
@@ -292,4 +295,5 @@ class CompressedTensorsMoEMethod(FusedMoEMethodBase):
             topk_ids,
             w1_scale=layer.w13_weight_scale,
             w2_scale=layer.w2_weight_scale,
+            num_bits=self.num_bits,
         )

vllm/model_executor/layers/quantization/gptq_marlin.py

@@ -611,4 +611,5 @@ class GPTQMarlinMoEMethod(FusedMoEMethodBase):
             topk_ids,
             w1_scale=layer.w13_scales,
             w2_scale=layer.w2_scales,
+            num_bits=self.quant_config.quant_type.size_bits,
         ).to(orig_dtype)

vllm/model_executor/model_loader/utils.py

@@ -23,13 +23,7 @@ def get_model_architecture(
     architectures = getattr(model_config.hf_config, "architectures", [])
     # Special handling for quantized Mixtral.
     # FIXME(woosuk): This is a temporary hack.
-    mixtral_supported = ["fp8", "compressed-tensors"]
-    # for gptq_marlin, only run fused MoE for int4
-    if model_config.quantization == "gptq_marlin":
-        hf_quant_config = getattr(model_config.hf_config,
-                                  "quantization_config", None)
-        if hf_quant_config and hf_quant_config.get("bits") == 4:
-            mixtral_supported.append("gptq_marlin")
+    mixtral_supported = ["fp8", "compressed-tensors", "gptq_marlin"]
 
     if (model_config.quantization is not None
             and model_config.quantization not in mixtral_supported