Fp8 MoE optimizations on AMD (#2388)

python/sglang/srt/layers/fused_moe_triton/fused_moe.py

@@ -16,6 +16,7 @@ from vllm import _custom_ops as ops
 from sglang.srt.utils import direct_register_custom_op, get_device_name
 
 logger = logging.getLogger(__name__)
+padding_size = 128 if bool(int(os.getenv("MOE_PADDING", "0"))) else 0
 
 
 @triton.jit
@@ -58,6 +59,7 @@ def fused_moe_kernel(
     compute_type: tl.constexpr,
     use_fp8_w8a8: tl.constexpr,
     use_int8_w8a16: tl.constexpr,
+    even_Ks: tl.constexpr,
 ):
     """
     Implements the fused computation for a Mixture of Experts (MOE) using
@@ -143,12 +145,21 @@ def fused_moe_kernel(
     for k in range(0, tl.cdiv(K, BLOCK_SIZE_K)):
         # Load the next block of A and B, generate a mask by checking the
         # K dimension.
-        a = tl.load(
-            a_ptrs,
-            mask=token_mask[:, None] & (offs_k[None, :] < K - k * BLOCK_SIZE_K),
-            other=0.0,
-        )
-        b = tl.load(b_ptrs, mask=offs_k[:, None] < K - k * BLOCK_SIZE_K, other=0.0)
+        if even_Ks:
+            a = tl.load(
+                a_ptrs,
+                mask=token_mask[:, None],
+                other=0.0,
+            )
+            b = tl.load(b_ptrs)
+        else:
+            a = tl.load(
+                a_ptrs,
+                mask=token_mask[:, None] & (offs_k[None, :] < K - k * BLOCK_SIZE_K),
+                other=0.0,
+            )
+            b = tl.load(b_ptrs, mask=offs_k[:, None] < K - k * BLOCK_SIZE_K, other=0.0)
+
         # We accumulate along the K dimension.
         if use_int8_w8a16:
             accumulator = tl.dot(a, b.to(compute_type), acc=accumulator)
@@ -254,7 +265,9 @@ def invoke_fused_moe_kernel(
     assert topk_weights.stride(1) == 1
     assert sorted_token_ids.stride(0) == 1
 
+    padded_size = 0
     if use_fp8_w8a8:
+        padded_size = padding_size
         A, A_scale = ops.scaled_fp8_quant(A, A_scale)
         assert B_scale is not None
     elif use_int8_w8a16:
@@ -268,6 +281,12 @@ def invoke_fused_moe_kernel(
         * triton.cdiv(B.shape[1], META["BLOCK_SIZE_N"]),
     )
 
+    K = B.shape[2] - padded_size
+    if K % config["BLOCK_SIZE_K"] == 0:
+        even_Ks = True
+    else:
+        even_Ks = False
+
     fused_moe_kernel[grid](
         A,
         B,
@@ -279,7 +298,7 @@ def invoke_fused_moe_kernel(
         expert_ids,
         num_tokens_post_padded,
         B.shape[1],
-        B.shape[2],
+        B.shape[2] - padded_size,
         sorted_token_ids.shape[0],
         topk_ids.numel(),
         A.stride(0),
@@ -296,6 +315,7 @@ def invoke_fused_moe_kernel(
         compute_type=compute_type,
         use_fp8_w8a8=use_fp8_w8a8,
         use_int8_w8a16=use_int8_w8a16,
+        even_Ks=even_Ks,
         **config,
     )
 
@@ -351,20 +371,39 @@ def get_default_config(
     dtype: Optional[str],
     is_marlin: bool,
 ) -> Dict[str, int]:
-    config = {
-        "BLOCK_SIZE_M": 64,
-        "BLOCK_SIZE_N": 64,
-        "BLOCK_SIZE_K": 32,
-        "GROUP_SIZE_M": 8,
-    }
-    # A heuristic: fused marlin works faster with this config for small M
-    if M <= E or (is_marlin and M <= 32):
+    if dtype == "fp8_w8a8":
         config = {
-            "BLOCK_SIZE_M": 16,
-            "BLOCK_SIZE_N": 32,
-            "BLOCK_SIZE_K": 64,
-            "GROUP_SIZE_M": 1,
+            "BLOCK_SIZE_M": 128,
+            "BLOCK_SIZE_N": 256,
+            "BLOCK_SIZE_K": 128,
+            "GROUP_SIZE_M": 32,
+            "num_warps": 8,
+            "num_stages": 4,
         }
+        if M <= E:
+            config = {
+                "BLOCK_SIZE_M": 64,
+                "BLOCK_SIZE_N": 128,
+                "BLOCK_SIZE_K": 128,
+                "GROUP_SIZE_M": 1,
+                "num_warps": 4,
+                "num_stages": 4,
+            }
+    else:
+        config = {
+            "BLOCK_SIZE_M": 64,
+            "BLOCK_SIZE_N": 64,
+            "BLOCK_SIZE_K": 32,
+            "GROUP_SIZE_M": 8,
+        }
+        # A heuristic: fused marlin works faster with this config for small M
+        if M <= E or (is_marlin and M <= 32):
+            config = {
+                "BLOCK_SIZE_M": 16,
+                "BLOCK_SIZE_N": 32,
+                "BLOCK_SIZE_K": 64,
+                "GROUP_SIZE_M": 1,
+            }
     return config
 
 
@@ -645,8 +684,12 @@ def fused_experts_impl(
     a1_scale: Optional[torch.Tensor] = None,
     a2_scale: Optional[torch.Tensor] = None,
 ):
+    padded_size = padding_size
+    if not use_fp8_w8a8:
+        padded_size = 0
+
     # Check constraints.
-    assert hidden_states.shape[1] == w1.shape[2], "Hidden size mismatch"
+    assert hidden_states.shape[1] == w1.shape[2] - padded_size, "Hidden size mismatch"
     assert topk_weights.shape == topk_ids.shape, "topk shape mismatch"
     assert hidden_states.is_contiguous(), "Hidden_states must be contiguous"
     assert w1.is_contiguous(), "Expert weights1 must be contiguous"
@@ -668,7 +711,7 @@ def fused_experts_impl(
     get_config_func = functools.partial(
         try_get_optimal_moe_config,
         w1.shape,
-        w2.shape,
+        (w2.shape[0], w2.shape[1], w2.shape[2] - padded_size),
         topk_ids.shape[1],
         config_dtype,
     )

python/sglang/srt/layers/quantization/fp8.py

 # Adapted from https://github.com/vllm-project/vllm/blob/v0.6.4.post1/vllm/model_executor/layers/quantization/fp8.py
 
 import logging
+import os
 from typing import Any, Callable, Dict, List, Optional
 
 import torch
+import torch.nn.functional as F
 from torch.nn import Module
 from torch.nn.parameter import Parameter
 from vllm import _custom_ops as ops
@@ -24,6 +26,7 @@ from vllm.model_executor.layers.quantization.utils.w8a8_utils import (
 )
 from vllm.model_executor.parameter import ModelWeightParameter, PerTensorScaleParameter
 
+from sglang.srt.layers.fused_moe_triton.fused_moe import padding_size
 from sglang.srt.layers.linear import LinearMethodBase, UnquantizedLinearMethod
 from sglang.srt.layers.quantization.base_config import (
     QuantizationConfig,
@@ -420,7 +423,7 @@ class Fp8MoEMethod:
 
     def process_weights_after_loading(self, layer: Module) -> None:
 
-        # If checkpoint is fp16, quantize in place.
+        # If checkpoint is fp16 or bfloat16, quantize in place.
         if not self.quant_config.is_checkpoint_fp8_serialized:
             # If ROCm, use float8_e4m3fnuz instead (MI300x HW)
             fp8_dtype = torch.float8_e4m3fnuz if is_hip() else torch.float8_e4m3fn
@@ -444,6 +447,19 @@ class Fp8MoEMethod:
                 )
             layer.w13_weight = torch.nn.Parameter(w13_weight, requires_grad=False)
             layer.w2_weight = torch.nn.Parameter(w2_weight, requires_grad=False)
+
+            # If ROCm, apply weight padding (min. Mem channel contention) only if set
+            if is_hip() and bool(int(os.getenv("MOE_PADDING", "0"))):
+                layer.w13_weight = torch.nn.Parameter(
+                    F.pad(layer.w13_weight.data, (0, padding_size), "constant", 0),
+                    requires_grad=False,
+                )
+                torch.cuda.empty_cache()
+                layer.w2_weight = torch.nn.Parameter(
+                    F.pad(layer.w2_weight.data, (0, padding_size), "constant", 0),
+                    requires_grad=False,
+                )
+                torch.cuda.empty_cache()
             return
 
         # If checkpoint is fp8, we need to handle that the
@@ -472,6 +488,7 @@ class Fp8MoEMethod:
                 layer.w2_input_scale = torch.nn.Parameter(
                     layer.w2_input_scale.max(), requires_grad=False
                 )
+
             # If ROCm, normalize the weights and scales to e4m3fnuz
             if is_hip():
                 # Normalize the weights and scales
@@ -523,6 +540,19 @@ class Fp8MoEMethod:
             layer.w13_weight_scale = torch.nn.Parameter(
                 max_w13_scales, requires_grad=False
             )
+
+            # If ROCm, apply weight padding (min. Mem channel contention) only if set
+            if is_hip() and bool(int(os.getenv("MOE_PADDING", "0"))):
+                layer.w13_weight = torch.nn.Parameter(
+                    F.pad(layer.w13_weight.data, (0, padding_size), "constant", 0),
+                    requires_grad=False,
+                )
+                torch.cuda.empty_cache()
+                layer.w2_weight = torch.nn.Parameter(
+                    F.pad(layer.w2_weight.data, (0, padding_size), "constant", 0),
+                    requires_grad=False,
+                )
+                torch.cuda.empty_cache()
             return
 
     def apply(
@@ -540,6 +570,7 @@ class Fp8MoEMethod:
         from sglang.srt.layers.fused_moe_triton import FusedMoE
         from sglang.srt.layers.fused_moe_triton.fused_moe import fused_experts
 
+        # Expert selection
         topk_weights, topk_ids = FusedMoE.select_experts(
             hidden_states=x,
             router_logits=router_logits,
@@ -551,6 +582,7 @@ class Fp8MoEMethod:
             custom_routing_function=custom_routing_function,
         )
 
+        # Expert fusion with FP8 quantization
         return fused_experts(
             x,
             layer.w13_weight,