test(cdclient): benchmark startup and a big inventory with and without the fdb

Skipped unless DLU_FDB_BENCH_XML names a character save; prints startup
time, inventory load time and resident memory (private and file-backed,
on Linux) for DLU_FDB_BENCH_MODE=fdb or sqlite.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/dGameTests/CDFdbBenchmark.cpp

@@ -0,0 +1,105 @@
+#include "GameDependencies.h"
+
+#include <chrono>
+#include <cstdlib>
+#include <filesystem>
+#include <fstream>
+#include <iostream>
+#include <string>
+
+#include "CDClientDatabase.h"
+#include "CDClientManager.h"
+#include "CDComponentsRegistryTable.h"
+#include "CDFdb.h"
+#include "CDItemComponentTable.h"
+#include "CDObjectsTable.h"
+#include "Entity.h"
+#include "InventoryComponent.h"
+#include "tinyxml2.h"
+
+#include <gtest/gtest.h>
+
+// Startup and inventory load with and without the fdb. Skipped unless DLU_FDB_BENCH_XML names a
+// character save (charxml) to load; run once per mode, each in its own process:
+//   DLU_FDB_BENCH_MODE=fdb|sqlite DLU_CLIENT_RES=<client res> DLU_CDSERVER_SQLITE=<CDServer.sqlite>
+//   DLU_FDB_BENCH_XML=<charxml> dGameTests --gtest_filter=CDFdbBenchmark.*
+namespace {
+	// Resident memory in KiB: anonymous (private to the process) and file-backed (shareable)
+	struct Rss {
+		int64_t anon = -1;
+		int64_t file = -1;
+	};
+
+	Rss ReadRss() {
+		Rss rss;
+#ifdef __linux__
+		std::ifstream status("/proc/self/status");
+		std::string key;
+		while (status >> key) {
+			if (key == "RssAnon:") status >> rss.anon;
+			else if (key == "RssFile:") status >> rss.file;
+			else status.ignore(1024, '\n');
+		}
+#endif
+		return rss;
+	}
+
+	double MillisecondsSince(std::chrono::steady_clock::time_point start) {
+		return std::chrono::duration<double, std::milli>(std::chrono::steady_clock::now() - start).count();
+	}
+}
+
+class CDFdbBenchmark : public GameDependenciesTest {
+protected:
+	void TearDown() override {
+		if (!IsSkipped()) TearDownDependencies();
+	}
+};
+
+TEST_F(CDFdbBenchmark, StartupAndInventoryLoad) {
+	const char* xmlPath = std::getenv("DLU_FDB_BENCH_XML");
+	const char* sqlitePath = std::getenv("DLU_CDSERVER_SQLITE");
+	if (!xmlPath || !sqlitePath) GTEST_SKIP() << "Set DLU_FDB_BENCH_XML and DLU_CDSERVER_SQLITE to run the benchmark";
+	const std::string mode = std::getenv("DLU_FDB_BENCH_MODE") ? std::getenv("DLU_FDB_BENCH_MODE") : "fdb";
+	std::filesystem::path fdbPath;
+	if (mode == "fdb") {
+		const char* res = std::getenv("DLU_CLIENT_RES");
+		if (!res) GTEST_SKIP() << "Set DLU_CLIENT_RES for the fdb mode";
+		fdbPath = std::filesystem::path(res) / "cdclient.fdb";
+	}
+
+	SetUpDependencies();
+	CDClientDatabase::Connect(sqlitePath);
+	CDClientDatabase::ExecuteDML("PRAGMA query_only = ON;");
+
+	const auto before = ReadRss();
+	const auto startupStart = std::chrono::steady_clock::now();
+	CDClientManager::LoadValuesFromDatabase(fdbPath);
+	const auto startupMs = MillisecondsSince(startupStart);
+	const auto afterStartup = ReadRss();
+	if (mode == "fdb") ASSERT_NE(CDFdb::Get(), nullptr);
+
+	tinyxml2::XMLDocument doc;
+	ASSERT_EQ(doc.LoadFile(xmlPath), tinyxml2::XML_SUCCESS);
+
+	CDClientManager::GetEntriesMutable<CDComponentsRegistryTable>().insert_or_assign(static_cast<uint64_t>(info.lot), 0);
+	auto entity = std::make_unique<Entity>(1, info);
+	auto* inventory = entity->AddComponent<InventoryComponent>(-1);
+
+	const auto loadStart = std::chrono::steady_clock::now();
+	inventory->LoadXml(doc);
+	const auto loadMs = MillisecondsSince(loadStart);
+	const auto afterLoad = ReadRss();
+
+	uint32_t items = 0;
+	for (const auto& [type, bag] : inventory->GetInventories()) items += static_cast<uint32_t>(bag->GetItems().size());
+
+	std::cout << "mode=" << mode
+		<< " startup_ms=" << startupMs
+		<< " inventory_load_ms=" << loadMs << " items=" << items
+		<< " rss_anon_kib before=" << before.anon << " after_startup=" << afterStartup.anon << " after_load=" << afterLoad.anon
+		<< " rss_file_kib before=" << before.file << " after_startup=" << afterStartup.file << " after_load=" << afterLoad.file
+		<< std::endl;
+
+	entity.reset();
+}

tests/dGameTests/CMakeLists.txt

@@ -28,6 +28,7 @@ set(DGAMETEST_SOURCES
 	"SpiderQueenTests.cpp"
 	"TacArcTests.cpp"
 	"CDFdbTests.cpp"
+	"CDFdbBenchmark.cpp"
 )
 
 add_subdirectory(dComponentsTests)