Support Triton fp8 e5m2 kv cache (#1286)

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

python/sglang/srt/layers/extend_attention.py

@@ -128,7 +128,7 @@ def _fwd_kernel(
         k = tl.load(K_Buffer + offs_buf_k, mask=mask_n[None, :], other=0.0)
 
         qk = tl.zeros([BLOCK_M, BLOCK_N], dtype=tl.float32)
-        qk += tl.dot(q, k)
+        qk += tl.dot(q.to(k.dtype), k)
         if BLOCK_DPE > 0:
             offs_kpe = (
                 offs_kv_loc[None, :] * stride_buf_kbs
@@ -140,7 +140,7 @@ def _fwd_kernel(
                 mask=mask_n[None, :],
                 other=0.0,
             )
-            qk += tl.dot(qpe, kpe)
+            qk += tl.dot(qpe.to(kpe.dtype), kpe)
         qk *= sm_scale
 
         if logit_cap > 0:
@@ -276,9 +276,17 @@ def extend_attention_fwd(
     BLOCK_DV = Lv
 
     if CUDA_CAPABILITY[0] >= 9:
-        BLOCK_M, BLOCK_N = (128, 64)
+        if Lq <= 256:
+            BLOCK_M, BLOCK_N = (128, 64)
+        else:
+            BLOCK_M, BLOCK_N = (32, 64)
     elif CUDA_CAPABILITY[0] >= 8:
-        BLOCK_M, BLOCK_N = (128, 128) if Lq <= 128 else (64, 64)
+        if Lq <= 128:
+            BLOCK_M, BLOCK_N = (128, 128)
+        elif Lq <= 256:
+            BLOCK_M, BLOCK_N = (64, 64)
+        else:
+            BLOCK_M, BLOCK_N = (32, 64)
     else:
         BLOCK_M, BLOCK_N = (64, 64) if Lq <= 128 else (32, 32)
 

python/sglang/srt/model_executor/model_runner.py

@@ -348,13 +348,7 @@ class ModelRunner:
         if self.server_args.kv_cache_dtype == "auto":
             self.kv_cache_dtype = self.dtype
         elif self.server_args.kv_cache_dtype == "fp8_e5m2":
-            if self.server_args.disable_flashinfer or self.server_args.enable_mla:
-                logger.warning(
-                    "FP8 KV cache is not supported for Triton kernel now, using auto kv cache dtype"
-                )
-                self.kv_cache_dtype = self.dtype
-            else:
-                self.kv_cache_dtype = torch.float8_e5m2
+            self.kv_cache_dtype = torch.float8_e5m2
         else:
             raise ValueError(
                 f"Unsupported kv_cache_dtype: {self.server_args.kv_cache_dtype}."