From f5d9ed02c839f67d13ea846b88fc5fc8b250ac5a Mon Sep 17 00:00:00 2001
From: Pavel Tsayukov <p.tsayukov@gmail.com>
Date: Mon, 2 Sep 2024 14:53:27 +0300
Subject: [PATCH 1/2] Add benchmark-clobber library (#296)

---
 src/library/CMakeLists.txt           |  4 ++++
 src/library/benchmark/CMakeLists.txt |  1 +
 src/library/benchmark/clobber.h      | 26 ++++++++++++++++++++++++++
 util/CMakeLists.txt                  | 18 +++++++++++++-----
 4 files changed, 44 insertions(+), 5 deletions(-)
 create mode 100644 src/library/benchmark/CMakeLists.txt
 create mode 100644 src/library/benchmark/clobber.h

diff --git a/src/library/CMakeLists.txt b/src/library/CMakeLists.txt
index 96fed21fca..a1f8aeb527 100644
--- a/src/library/CMakeLists.txt
+++ b/src/library/CMakeLists.txt
@@ -1,3 +1,7 @@
+if (YDB_SDK_TESTS)
+  add_subdirectory(benchmark)
+endif()
+
 add_subdirectory(grpc/client)
 add_subdirectory(json_value)
 add_subdirectory(jwt)
diff --git a/src/library/benchmark/CMakeLists.txt b/src/library/benchmark/CMakeLists.txt
new file mode 100644
index 0000000000..90a15166bf
--- /dev/null
+++ b/src/library/benchmark/CMakeLists.txt
@@ -0,0 +1 @@
+_ydb_sdk_add_library(benchmark-clobber INTERFACE)
diff --git a/src/library/benchmark/clobber.h b/src/library/benchmark/clobber.h
new file mode 100644
index 0000000000..f8ce28a3f1
--- /dev/null
+++ b/src/library/benchmark/clobber.h
@@ -0,0 +1,26 @@
+#pragma once
+
+#include <util/system/compiler.h>
+
+namespace NBench {
+
+/**
+ * Functions that states "I can read and write everywhere in memory".
+ *
+ * Use it to prevent optimizer from reordering or discarding memory writes prior
+ * to it's call, and force memory reads after it's call.
+ */
+Y_FORCE_INLINE void Clobber() {
+#if defined(__GNUC__)
+    asm volatile(""
+                 :
+                 :
+                 : "memory");
+#elif defined(_MSC_VER)
+    _ReadWriteBarrier();
+#else
+    // Otherwise, do nothing
+#endif
+}
+
+} // namespace NBench
diff --git a/util/CMakeLists.txt b/util/CMakeLists.txt
index a4bddaca3f..994e5163a2 100644
--- a/util/CMakeLists.txt
+++ b/util/CMakeLists.txt
@@ -310,12 +310,7 @@ if (YDB_SDK_TESTS)
       system/thread_ut.cpp
 
       system/types_ut.cpp
-
-      # TODO: add library/cpp/testing/benchmark
-      #       depends only on NBench::Clobber, that's a memory optimization barrier
-      # system/unaligned_mem_ut.cpp
       system/user_ut.cpp
-
       system/yassert_ut.cpp
     LINK_LIBRARIES
       yutil
@@ -324,6 +319,19 @@ if (YDB_SDK_TESTS)
       unit
   )
 
+  add_ydb_test(NAME util-system-unaligned_mem_ut
+    WORKING_DIRECTORY
+      ${CMAKE_CURRENT_BINARY_DIR}/system
+    SOURCES
+      system/unaligned_mem_ut.cpp
+    LINK_LIBRARIES
+      yutil
+      benchmark-clobber
+      cpp-testing-unittest_main
+    LABELS
+      unit
+  )
+
   add_ydb_test(NAME util-system-fstat_ut
     WORKING_DIRECTORY
       ${CMAKE_CURRENT_BINARY_DIR}/system

From 745637686a8e0fe6acff38a3fe2acc471bed9cdc Mon Sep 17 00:00:00 2001
From: Pavel Tsayukov <p.tsayukov@gmail.com>
Date: Mon, 2 Sep 2024 14:53:53 +0300
Subject: [PATCH 2/2] Replace include (#296)

---
 util/system/unaligned_mem_ut.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/util/system/unaligned_mem_ut.cpp b/util/system/unaligned_mem_ut.cpp
index 9de3f3e931..ac135752aa 100644
--- a/util/system/unaligned_mem_ut.cpp
+++ b/util/system/unaligned_mem_ut.cpp
@@ -1,6 +1,6 @@
 #include "unaligned_mem.h"
 
-#include <library/cpp/testing/benchmark/bench.h>
+#include <src/library/benchmark/clobber.h>
 #include <library/cpp/testing/unittest/registar.h>
 
 #include <util/system/compiler.h>