[Kernel] Set sgl_per_token_group_quant_8bit_v2 as default choice (#22467)

python/sglang/srt/environ.py

@@ -3,7 +3,7 @@ import subprocess
 import warnings
 from contextlib import ExitStack, contextmanager
 from enum import IntEnum
-from typing import Any
+from typing import Any, Optional
 
 
 @contextmanager
@@ -341,7 +341,6 @@ class Envs:
     SGLANG_FORCE_FP8_MARLIN = EnvBool(False)
     SGLANG_MOE_NVFP4_DISPATCH = EnvBool(False)
     SGLANG_NVFP4_CKPT_FP8_GEMM_IN_ATTN = EnvBool(False)
-    SGLANG_PER_TOKEN_GROUP_QUANT_8BIT_V2 = EnvBool(False)
     SGLANG_NVFP4_CKPT_FP8_NEXTN_MOE = EnvBool(False)
     SGLANG_QUANT_ALLOW_DOWNCASTING = EnvBool(False)
     SGLANG_FP8_IGNORED_LAYERS = EnvStr("")
@@ -552,12 +551,15 @@ envs = Envs()
 EnvField._allow_set_name = False
 
 
-def _print_deprecated_env(new_name: str, old_name: str):
+def _print_deprecated_env(old_name: str, new_name: Optional[str] = None):
     if old_name in os.environ:
-        warnings.warn(
-            f"Environment variable {old_name} will be deprecated, please use {new_name} instead"
-        )
-        os.environ[new_name] = os.environ[old_name]
+        if new_name is None:
+            warnings.warn(f"Environment variable {old_name} has been deprecated.")
+        else:
+            warnings.warn(
+                f"Environment variable {old_name} will be deprecated, please use {new_name} instead"
+            )
+            os.environ[new_name] = os.environ[old_name]
 
 
 def _warn_deprecated_env_to_cli_flag(env_name: str, suggestion: str):
@@ -570,14 +572,15 @@ def _warn_deprecated_env_to_cli_flag(env_name: str, suggestion: str):
 
 
 def _convert_SGL_to_SGLANG():
-    _print_deprecated_env("SGLANG_LOG_GC", "SGLANG_GC_LOG")
+    _print_deprecated_env("SGLANG_GC_LOG", "SGLANG_LOG_GC")
     _print_deprecated_env(
-        "SGLANG_MOE_NVFP4_DISPATCH", "SGLANG_CUTEDSL_MOE_NVFP4_DISPATCH"
+        "SGLANG_CUTEDSL_MOE_NVFP4_DISPATCH", "SGLANG_MOE_NVFP4_DISPATCH"
     )
     _print_deprecated_env(
-        "SGLANG_ENABLE_TP_MEMORY_INBALANCE_CHECK",
         "SGL_DISABLE_TP_MEMORY_INBALANCE_CHECK",
+        "SGLANG_ENABLE_TP_MEMORY_INBALANCE_CHECK",
     )
+    _print_deprecated_env("SGLANG_PER_TOKEN_GROUP_QUANT_8BIT_V2")
     _deprecated_ms_to_s = {
         "SGLANG_QUEUED_TIMEOUT_MS": "SGLANG_REQ_WAITING_TIMEOUT",
         "SGLANG_FORWARD_TIMEOUT_MS": "SGLANG_REQ_RUNNING_TIMEOUT",

python/sglang/srt/layers/quantization/fp8_kernel.py

@@ -324,10 +324,6 @@ def _per_token_group_quant_8bit_raw(
     return x_q, x_s
 
 
-# backward compatibility
-per_token_group_quant_fp8 = _per_token_group_quant_8bit_raw
-
-
 def _per_token_group_quant_8bit_fuse_silu_and_mul(
     x: torch.Tensor,
     group_size: int,
@@ -507,6 +503,11 @@ def sglang_per_token_group_quant_fp8(
         scale_ue8m0=scale_ue8m0,
     )
 
+    # Enable v2 kernel by default on supported group sizes
+    _V2_KERNEL_SUPPORTED_GROUP_SIZES = [16, 32, 64, 128]
+    if enable_v2 is None:
+        enable_v2 = group_size in _V2_KERNEL_SUPPORTED_GROUP_SIZES
+
     if x.shape[0] > 0:
         # Temporary
         if enable_sgl_per_token_group_quant_8bit:
@@ -606,6 +607,12 @@ def sglang_per_token_quant_fp8(
     return x_q, x_s
 
 
+if _is_cuda:
+    per_token_group_quant_fp8 = sglang_per_token_group_quant_fp8
+else:
+    per_token_group_quant_fp8 = _per_token_group_quant_8bit_raw
+
+
 @triton.jit
 def _static_quant_fp8(
     # Pointers to inputs and output