diag: probe ixformer paged attention signature

probe_paged_attn.py

@@ -0,0 +1,28 @@
+#!/usr/bin/env python3
+"""Probe ixformer.vllm_single_query_cached_kv_attention signature and test."""
+import inspect
+import torch
+import ixformer
+
+# Print signature
+fn = ixformer.vllm_single_query_cached_kv_attention
+print(f"Signature: {inspect.signature(fn)}")
+
+# Also check v2
+if hasattr(ixformer, 'vllm_single_query_cached_kv_attention_v2'):
+    fn2 = ixformer.vllm_single_query_cached_kv_attention_v2
+    print(f"V2 Signature: {inspect.signature(fn2)}")
+
+# Check contrib.vllm_flash_attn if available
+try:
+    from ixformer.contrib import vllm_flash_attn
+    print(f"\nvllm_flash_attn dir: {[x for x in dir(vllm_flash_attn) if not x.startswith('_')]}")
+except Exception as e:
+    print(f"\nvllm_flash_attn: {e}")
+
+# Check ixformer.vllm submodule
+try:
+    import ixformer.vllm as ixv
+    print(f"\nixformer.vllm dir: {[x for x in dir(ixv) if not x.startswith('_')]}")
+except Exception as e:
+    print(f"\nixformer.vllm: {e}")