MB-52812: Fix engine benchmark fixture resource isolation

Improve ep_engine_benchmarks infrastructure with proper resource
isolation and intelligent test registration:

EngineFixture improvements:
- Use cb::io::mkdtemp() to create unique temporary directories instead of
  hardcoded 'benchmarks-test', eliminating race conditions when multiple
  benchmark instances run concurrently
- Store the generated dbname path as a member variable for proper cleanup
- Use fmt::format() for cleaner string composition
- Add defensive check before cleanup to prevent accidental deletion

CMakeLists.txt improvements:
- Normalize to lowercase CMake commands (modern convention)
- Remove unused GTest dependencies (pure benchmark suite)
- Streamline include directories
- Intelligently register 18 individual benchmark tests with CTest:
  * Only run on non-sanitizer builds (avoid timeouts)
  * Use separate test entries for each benchmark for targeted execution
  * Regex filtering (--benchmark_filter=^name) to run benchmarks in
    isolation
  * Fast execution mode (--benchmark_min_time=0.0000001s)
- Document problematic benchmarks that need resolution

Change-Id: I06ce09315c9514b2dcc69a6a829d905f8965a7b1
Reviewed-on: https://review.couchbase.org/c/kv_engine/+/245350
Tested-by: Build Bot <build@couchbase.com>
Reviewed-by: Jim Walker <jim@couchbase.com>

Author: trondn

engines/ep/CMakeLists.txt

@@ -528,21 +528,62 @@ cb_add_test_executable(ep_engine_benchmarks
                ${Memcached_SOURCE_DIR}/engines/ep/tests/module_tests/test_helpers.cc)
 kv_enable_pch(ep_engine_benchmarks)
 
-TARGET_LINK_LIBRARIES(ep_engine_benchmarks
+target_link_libraries(ep_engine_benchmarks
         PRIVATE
                 ep
                 mock_dcp
                 ep_mocks
                 couchstore_test_fileops
                 benchmark::benchmark
                 cluster_framework
-                GTest::gtest
-                GTest::gmock
                 platform_cb_malloc_arena)
-TARGET_INCLUDE_DIRECTORIES(ep_engine_benchmarks PUBLIC
-                           tests
-                           benchmarks
-                           ${Couchstore_SOURCE_DIR})
+target_include_directories(ep_engine_benchmarks PUBLIC tests)
+
+# MB-52812 Run the benchmarks on non-sanitizer builds only as some of the
+# benchmarks are not expected to run in a reasonable time when built with
+# sanitizers.
+# Ideally we could have just run the ep_engine_benchmark binary directly,
+# but there are a few benchmarks which currently don't work. While
+# trying to resolve them try to run each test individually.
+if (NOT CB_SANITIZERS)
+    function(add_benchmark_test benchmark_name)
+        add_test(NAME ep_engine_benchmarks-${benchmark_name}
+                WORKING_DIRECTORY ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}
+                COMMAND ep_engine_benchmarks --benchmark_min_time=0.0000001s
+                                             --benchmark_filter=^${benchmark_name})
+    endfunction()
+
+    # The following tests currently don't work
+    # add_benchmark_test(AccessLogBenchEngine)
+
+    # The following test should probably be deleted as it
+    # starts with the following comment:
+    #  "Skip this test as it's not working."
+    # add_benchmark_test(QuotaSharingBench)
+
+    add_benchmark_test(BM_CheckpointIteratorCompare)
+    add_benchmark_test(BM_CompareQueuedItemsBySeqnoAndKey)
+    add_benchmark_test(BM_SaturateCounter)
+    add_benchmark_test(CheckpointBench)
+    add_benchmark_test(DcpProducerStreamsMapBench)
+    add_benchmark_test(DefragmentBench)
+    add_benchmark_test(EngineStatsBench)
+    add_benchmark_test(ExecutorPoolFixture<FollyExecutorPool>)
+    add_benchmark_test(HashTableBench)
+    add_benchmark_test(ItemCompressorBench)
+    add_benchmark_test(KVStoreBench)
+    add_benchmark_test(MemTrackingVBucketBench)
+    add_benchmark_test(MultiVBEngineStatsBench)
+    add_benchmark_test(PagingVisitorBench)
+    add_benchmark_test(PureFollyExecutorBench)
+    add_benchmark_test(SessionTracingEncode)
+    add_benchmark_test(SessionTracingRecordMutationSpan)
+    add_benchmark_test(SessionTracingScopeTimer)
+    add_benchmark_test(StatsBench)
+    add_benchmark_test(VBCBAdaptorBench)
+    add_benchmark_test(VBReadyQueueBench)
+    add_benchmark_test(VBucketDetailsBench)
+endif ()
 
 add_sanitizers(ep_engine_benchmarks)
 cb_enable_unity_build(ep_engine_benchmarks)

engines/ep/benchmarks/engine_fixture.cc

@@ -26,14 +26,15 @@
 
 void EngineFixture::SetUp(const benchmark::State& state) {
     if (state.thread_index() == 0) {
+        dbname = cb::io::mkdtemp("benchmarks-test");
         {
             NonBucketAllocationGuard guard;
             ExecutorPool::create(ExecutorPool::Backend::Fake);
         }
         executorPool = reinterpret_cast<SingleThreadedExecutorPool*>(
                 ExecutorPool::get());
-        std::string config = "dbname=benchmarks-test;ht_locks=47;" + varConfig;
-
+        auto config = fmt::format(
+                "dbname={};ht_locks=47;{}", dbname.string(), varConfig);
         engine = SynchronousEPEngine::build(config);
 
         initialize_time_functions(get_mock_server_api()->core);
@@ -55,7 +56,9 @@ void EngineFixture::TearDown(const benchmark::State& state) {
         engine->getDcpConnMap().manageConnections();
         engine.reset();
         ExecutorPool::shutdown();
-        cb::io::remove_with_retry("benchmarks-test");
+        if (!dbname.empty()) {
+            cb::io::remove_with_retry(dbname.string());
+        }
     }
     ObjectRegistry::onSwitchThread(nullptr);
 }

engines/ep/benchmarks/engine_fixture.h

@@ -41,4 +41,5 @@ class EngineFixture : public benchmark::Fixture {
     // Allows subclasses to add stuff to the config
     std::string varConfig;
     SingleThreadedExecutorPool* executorPool;
+    std::filesystem::path dbname;
 };