feat(CRITICAL): 从 GitHub 扫描搬运 ixformer SDK + xllm 完整 GDN/MoE 代码

来源:
  1. Chranos/ixformer (GitHub) → ixformer_sdk/ (230 files, 70K lines)
     - inference/functions/vllm.py: vllm_moe_topk_softmax 完整实现 (2033 lines)
     - inference/functions/moe.py: MoE ops 完整实现 (1380 lines)
     - contrib/vllm_flash_attn/: FA2 Python 接口 (1018 lines)
     - contrib/tgi/fused_moe.py: TGI fused MoE (429 lines)
     - csrc/include/ixformer/: C++ kernel headers + cmake

  2. Deep-Spark/xllm (GitHub) → upstream_ref/xllm_latest/ (+15 files)
     - npu_torch/qwen3_5_decoder_layer_impl.cpp/.h
     - npu_torch/qwen3_5_gated_delta_net.cpp/.h
     - npu_torch/qwen3_next_*.cpp/.h (6 files)
     - npu_torch/attention.cpp/.h + fused_moe.cpp/.h + CMakeLists.txt
     - models/llm/qwen3_5.h + qwen3_5_mtp.h + qwen3_next.h
     - models/vlm/qwen3_5.h

调用链完整性:
  ixformer_sdk/inference/functions/vllm.py
    → ops.infer.moe_topk_softmax() (C++ 层)
    → 这就是 base 镜像 libixformer.so 里的实现

  upstream_ref/xllm_latest/core/layers/ilu/fused_moe.cpp
    → ixformer::infer::topk_softmax() (直接 C++ 调用)
    → ixformer::infer::group_gemm() → 完整 7-step MoE pipeline

ixformer_sdk/testing/memory_monitor.py

@@ -0,0 +1,37 @@
+from psutil import Process
+
+
+def get_current_memory(pid=None):
+    return Process(pid).memory_full_info()
+
+
+class MemoryMonitorContext(object):
+    def __init__(self, pid=None):
+        self._pid = pid
+
+        self.reset()
+
+    def __enter__(self):
+        self._enter_memory = self._get_used_memory()
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        self._exit_memory = self._get_used_memory()
+        return self
+
+    def _get_used_memory(self) -> float:
+        mem = get_current_memory(self._pid)
+        return mem.uss
+
+    def reset(self):
+        self._enter_memory = -1
+        self._exit_memory = -1
+
+    def delta(self) -> float:
+        if self._enter_memory < 0:
+            raise RuntimeError("Please using context manager to wrap your code.")
+
+        if self._exit_memory < 0:
+            return self._get_used_memory() - self._enter_memory
+
+        return self._exit_memory - self._enter_memory