Reland [1/2] Optimizations and refactors about quant kernel (#10312)

Co-authored-by: Yineng Zhang <me@zhyncs.com>

python/sglang/srt/layers/quantization/int8_kernel.py

@@ -8,11 +8,17 @@ import torch
 import triton
 import triton.language as tl
 
-from sglang.srt.utils import get_device_name, is_cuda
+from sglang.srt.utils import get_bool_env_var, get_device_name, is_cuda
 
 _is_cuda = is_cuda()
 if _is_cuda:
-    from sgl_kernel import sgl_per_token_group_quant_int8
+    # Temporary
+    try:
+        from sgl_kernel import sgl_per_token_group_quant_8bit
+    except ImportError:
+        from sgl_kernel import (
+            sgl_per_token_group_quant_int8 as sgl_per_token_group_quant_8bit,
+        )
 
 logger = logging.getLogger(__name__)
 
@@ -187,6 +193,7 @@ def sglang_per_token_group_quant_int8(
     group_size: int,
     eps: float = 1e-10,
     dtype: torch.dtype = torch.int8,
+    enable_v2: Optional[bool] = None,
 ):
     assert (
         x.shape[-1] % group_size == 0
@@ -204,7 +211,9 @@ def sglang_per_token_group_quant_int8(
         dtype=torch.float32,
     )
 
-    sgl_per_token_group_quant_int8(x, x_q, x_s, group_size, eps, int8_min, int8_max)
+    sgl_per_token_group_quant_8bit(
+        x, x_q, x_s, group_size, eps, int8_min, int8_max, enable_v2=enable_v2
+    )
 
     return x_q, x_s