Add a new fingerprinting method for XNNPack weight cache.

Warning: this new fingerprinting method is currently experimental.

Every operation in XNNPack that uses the weight cache should implement a
corresponding fingerprinting function. The goal of that fingerprint is to check
whether the pre-computation (packing) that takes place for this op has changed
and if a previous weight cache can be reused directly or not.

The expected way for this to work is that a fingerprint function would assume a
predetermined set of constant inputs passed to the create function and would
then hash the resulting cache buffer.

The `xnn_weights_cache_look_up_key` has a new field that holds the fingerprint
identifier. It is set by kernel setup functions when they try to do cache
look-ups.

PiperOrigin-RevId: 809079455

Author: qukhan

BUILD.bazel

@@ -140,6 +140,7 @@ xnnpack_cc_library(
         "include/xnnpack.h",
     ],
     deps = [
+        ":fingerprint_id",
         "@pthreadpool",
     ],
 )
@@ -773,6 +774,50 @@ xnnpack_cc_library(
     ],
 )
 
+xnnpack_cc_library(
+    name = "fingerprint_id",
+    hdrs = ["src/operators/fingerprint_id.h"],
+)
+
+xnnpack_cc_library(
+    name = "fingerprint_cache",
+    srcs = ["src/operators/fingerprint_cache.c"],
+    hdrs = ["src/operators/fingerprint_cache.h"],
+    deps = [
+        ":allocator",
+        ":cache",
+        ":fingerprint_id",
+        ":init_once",
+        ":mutex",
+        ":operator_delete",
+        ":xnnpack_h",
+    ],
+)
+
+xnnpack_cc_library(
+    name = "fingerprint_check",
+    srcs = ["src/xnnpack/fingerprint_check.c"],
+    deps = [
+        ":fingerprint_cache",
+        ":fingerprint_id",
+        ":operators",
+        ":xnnpack_h",
+    ],
+)
+
+xnnpack_cc_library(
+    name = "operator_delete",
+    srcs = ["src/operator-delete.c"],
+    deps = [
+        ":allocator",
+        ":logging",
+        ":operator_h",
+        ":operator_utils",
+        ":params",
+        ":xnnpack_h",
+    ],
+)
+
 xnnpack_cc_library(
     name = "operators",
     srcs = OPERATOR_SRCS,
@@ -804,6 +849,7 @@ xnnpack_cc_library(
         ":microparams_init",
         ":node_type",
         ":normalization",
+        ":operator_delete",
         ":operator_type",
         ":operator_utils",
         ":pack_lh",
@@ -932,6 +978,7 @@ xnnpack_cc_library(
             "//:allocator",
             "//:build_identifier",  # build_cleaner: keep
             "//:common",  # build_cleaner: keep
+            "//:fingerprint_id",
             "//:init_once",
             "//:logging",
             "//:math",  # build_cleaner: keep

CMakeLists.txt

@@ -939,6 +939,9 @@ IF(XNNPACK_BUILD_LIBRARY)
   ADD_LIBRARY(xnnpack-allocator OBJECT src/allocator.c)
   ADD_LIBRARY(xnnpack-cache OBJECT src/cache.c)
   ADD_LIBRARY(xnnpack-datatype OBJECT src/datatype.c)
+  ADD_LIBRARY(xnnpack-operator-delete OBJECT src/operator-delete.c)
+  ADD_LIBRARY(xnnpack-fingerprint-cache OBJECT src/operators/fingerprint_cache.c)
+  ADD_LIBRARY(xnnpack-fingerprint-check OBJECT src/xnnpack/fingerprint_check.c)
   ADD_LIBRARY(xnnpack-memory OBJECT src/memory.c)
   ADD_LIBRARY(xnnpack-microkernel-utils OBJECT src/microkernel-utils.c)
   ADD_LIBRARY(xnnpack-mutex OBJECT src/mutex.c)
@@ -962,21 +965,25 @@ IF(XNNPACK_BUILD_LIBRARY)
   TARGET_LINK_LIBRARIES(xnnpack-allocator PRIVATE xnnpack-base xnnpack-logging)
   TARGET_LINK_LIBRARIES(xnnpack-cache PRIVATE xnnpack-base xnnpack-logging)
   TARGET_LINK_LIBRARIES(xnnpack-datatype PRIVATE xnnpack-base)
+  TARGET_LINK_LIBRARIES(xnnpack-operator-delete PRIVATE xnnpack-base xnnpack-logging)
   TARGET_LINK_LIBRARIES(xnnpack-memory PRIVATE xnnpack-base xnnpack-logging)
   TARGET_LINK_LIBRARIES(xnnpack-microkernel-utils PRIVATE xnnpack-base xnnpack-hardware-config xnnpack-logging)
   TARGET_LINK_LIBRARIES(xnnpack-mutex PRIVATE xnnpack-base xnnpack-logging)
   TARGET_LINK_LIBRARIES(xnnpack-operators PRIVATE xnnpack-base xnnpack-allocator xnnpack-indirection
       xnnpack-logging xnnpack-microkernel-utils xnnpack-normalization xnnpack-operator-utils xnnpack-pack-lh xnnpack-packing
       xnnpack-reference-ukernels xnnpack-datatype)
+  TARGET_LINK_LIBRARIES(xnnpack-fingerprint-cache PRIVATE xnnpack-base xnnpack-allocator xnnpack-cache xnnpack-mutex xnnpack-operator-delete)
+  TARGET_LINK_LIBRARIES(xnnpack-fingerprint-check PRIVATE xnnpack-base xnnpack-fingerprint-cache xnnpack-operators)
   TARGET_LINK_LIBRARIES(xnnpack-operator-run PRIVATE xnnpack-base xnnpack-logging)
   TARGET_LINK_LIBRARIES(xnnpack-operator-utils PRIVATE xnnpack-base xnnpack-logging)
   TARGET_LINK_LIBRARIES(xnnpack-reference-ukernels PRIVATE xnnpack-base xnnpack-datatype)
   TARGET_LINK_LIBRARIES(xnnpack-subgraph PRIVATE xnnpack-base xnnpack-allocator xnnpack-logging xnnpack-memory xnnpack-mutex xnnpack-operators xnnpack-operator-run xnnpack-datatype)
   TARGET_LINK_LIBRARIES(XNNPACK PRIVATE xnnpack-base xnnpack-allocator xnnpack-cache
       xnnpack-hardware-config xnnpack-indirection xnnpack-memory xnnpack-microkernel-utils xnnpack-microparams-init
-      xnnpack-mutex xnnpack-normalization xnnpack-operators xnnpack-operator-run xnnpack-operator-utils xnnpack-pack-lh xnnpack-packing
-      xnnpack-microkernels-prod xnnpack-subgraph xnnpack-datatype xnnpack-reference-ukernels)
-  TARGET_LINK_LIBRARIES(XNNPACK PUBLIC pthreadpool xnnpack-logging)
+      xnnpack-mutex xnnpack-normalization xnnpack-operators xnnpack-operator-run
+      xnnpack-operator-utils xnnpack-pack-lh xnnpack-packing xnnpack-fingerprint-cache xnnpack-microkernels-prod
+      xnnpack-subgraph xnnpack-datatype xnnpack-reference-ukernels)
+  TARGET_LINK_LIBRARIES(XNNPACK PUBLIC pthreadpool xnnpack-logging xnnpack-fingerprint-check)
   SET_TARGET_PROPERTIES(XNNPACK PROPERTIES C_EXTENSIONS YES)
 ENDIF()
 IF(NOT MSVC)

build_srcs.bzl

@@ -12,7 +12,6 @@ Lists of target-specific sources used to build XNNPACK.
 """
 
 OPERATOR_SRCS = [
-    "src/operator-delete.c",
     "src/operator-run.c",
     "src/operators/argmax-pooling-nhwc.c",
     "src/operators/average-pooling-nhwc.c",

include/experimental.h

@@ -16,6 +16,7 @@
 #include <stdint.h>
 
 #include "include/xnnpack.h"
+#include "src/operators/fingerprint_id.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -98,6 +99,29 @@ enum xnn_status xnn_update_runtime_with_threadpool(
   xnn_runtime_t runtime,
   xnn_threadpool_t threadpool);
 
+
+typedef struct xnn_fingerprint* xnn_fingerprint_t;
+
+struct xnn_fingerprint {
+  enum xnn_fingerprint_id id;
+  uint32_t value;
+};
+
+/// Check whether the given configuration matches one that is currently in use.
+///
+/// @returns True if the configuration matches.
+bool xnn_check_fingerprint(struct xnn_fingerprint fingerprint);
+
+/// Return the fingerprint corresponding to the given id or NULL if it wasn't
+/// set.
+const struct xnn_fingerprint* xnn_get_fingerprint(enum xnn_fingerprint_id id);
+
+/// Set the given fingerprint.
+void xnn_set_fingerprint(struct xnn_fingerprint fingerprint);
+
+/// Clear all fingerprints that were computed until now.
+void xnn_clear_fingerprints();
+
 #ifdef __cplusplus
 }  // extern "C"
 #endif

include/xnnpack.h

@@ -1,7 +1,7 @@
 // Copyright (c) Facebook, Inc. and its affiliates.
 // All rights reserved.
 //
-// Copyright 2019 Google LLC
+// Copyright 2019-2025 Google LLC
 //
 // This source code is licensed under the BSD-style license found in the
 // LICENSE file in the root directory of this source tree.
@@ -15,6 +15,7 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#include "src/operators/fingerprint_id.h"
 #include <pthreadpool.h>
 
 #ifdef __cplusplus
@@ -2297,6 +2298,8 @@ struct xnn_weights_cache_look_up_key {
   const void* kernel;
   /// Pointer to the original bias, could be NULL.
   const void* bias;
+
+  enum xnn_fingerprint_id fingerprint_id;
 };
 
 /// A group of function pointers to manage weights cache. All functions may be