[CPU] fix all_reduce and all_gather (#6770)

Co-authored-by: blzheng <beilei.zheng@intel.com>

python/sglang/srt/utils.py

@@ -2612,3 +2612,12 @@ def get_cpu_ids_by_node():
 
     # ['0,1,2,3', '4,5,6,7', '8,9,10,11', '12,13,14,15', '16,17,18,19', '20,21,22,23']
     return cpu_ids
+
+
+def is_shm_available(dtype, world_size, local_size):
+    return (
+        cpu_has_amx_support()
+        and dtype in [torch.bfloat16, torch.float]
+        and world_size >= 1
+        and world_size == local_size
+    )