Fix run time error in ROCm platform (#5147)

Co-authored-by: wunhuang <wunhuang@amd.com>
Co-authored-by: root <root@dell300x-pla-t10-17.pla.dcgpu>

python/sglang/srt/layers/moe/router.py

@@ -5,6 +5,9 @@ import triton
 import triton.language as tl
 
 from sglang.srt.layers.moe.topk import fused_topk
+from sglang.srt.utils import is_hip
+
+_is_hip = is_hip()
 
 
 @triton.jit
@@ -116,10 +119,13 @@ def fused_moe_router_impl(
     topk_ids = torch.empty((bs, topk), dtype=torch.int32, device=x.device)
 
     grid = lambda meta: (bs,)
+
+    min_num_warps = 16 if _is_hip else 32
+
     config = {
         "BLOCK_SIZE": triton.next_power_of_2(hidden_dim),
         "num_warps": max(
-            min(triton.next_power_of_2(triton.cdiv(hidden_dim, 256)), 32), 4
+            min(triton.next_power_of_2(triton.cdiv(hidden_dim, 256)), min_num_warps), 4
         ),
     }