Add benchmarks for json string serialize/deserialize (#12258)

Co-authored-by: sfan5 <sfan5@live.de>

src/benchmark/CMakeLists.txt

@@ -0,0 +1,7 @@
+set (BENCHMARK_SRCS
+	${CMAKE_CURRENT_SOURCE_DIR}/benchmark.cpp
+	${CMAKE_CURRENT_SOURCE_DIR}/benchmark_serialize.cpp
+	PARENT_SCOPE)
+
+set (BENCHMARK_CLIENT_SRCS
+	PARENT_SCOPE)

src/benchmark/benchmark.cpp

@@ -0,0 +1,32 @@
+/*
+Minetest
+Copyright (C) 2022 Minetest Authors
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include "benchmark/benchmark.h"
+
+// This must be set in just this file
+#define CATCH_CONFIG_RUNNER
+#include "benchmark_setup.h"
+
+int run_benchmarks()
+{
+	int argc = 1;
+	const char *argv[] = { "MinetestBenchmark", NULL };
+	int errCount = Catch::Session().run(argc, argv);
+	return errCount ? 1 : 0;
+}

src/benchmark/benchmark.h

@@ -0,0 +1,26 @@
+/*
+Minetest
+Copyright (C) 2022 Minetest Authors
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#pragma once
+
+#include "config.h"
+
+#if BUILD_BENCHMARKS
+extern int run_benchmarks();
+#endif

src/benchmark/benchmark_serialize.cpp

@@ -0,0 +1,71 @@
+/*
+Minetest
+Copyright (C) 2022 Minetest Authors
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include "benchmark_setup.h"
+#include "util/serialize.h"
+#include <sstream>
+#include <ios>
+
+// Builds a string of exactly `length` characters by repeating `s` (rest cut off)
+static std::string makeRepeatTo(const std::string &s, size_t length)
+{
+	std::string v;
+	v.reserve(length + s.size());
+	for (size_t i = 0; i < length; i += s.size()) {
+		v += s;
+	}
+	v.resize(length);
+	return v;
+}
+
+#define BENCH3(_label, _chars, _length, _lengthlabel) \
+	BENCHMARK_ADVANCED("serializeJsonStringIfNeeded_" _lengthlabel "_" _label)(Catch::Benchmark::Chronometer meter) { \
+		std::string s = makeRepeatTo(_chars, _length); \
+		meter.measure([&] { return serializeJsonStringIfNeeded(s); }); \
+	}; \
+	BENCHMARK_ADVANCED("deSerializeJsonStringIfNeeded_" _lengthlabel "_" _label)(Catch::Benchmark::Chronometer meter) { \
+		std::string s = makeRepeatTo(_chars, _length); \
+		std::string serialized = serializeJsonStringIfNeeded(s); \
+		std::istringstream is(serialized, std::ios::binary); \
+		meter.measure([&] { \
+			is.clear(); \
+			is.seekg(0, std::ios::beg); \
+			return deSerializeJsonStringIfNeeded(is); \
+		}); \
+	};
+
+/* Both with and without a space character (' ') */
+#define BENCH2(_label, _chars, _length, _lengthlabel) \
+	BENCH3(_label, _chars, _length, _lengthlabel) \
+	BENCH3(_label "_with_space", " " _chars, _length, _lengthlabel) \
+
+/* Iterate over input lengths */
+#define BENCH1(_label, _chars) \
+	BENCH2(_label, _chars, 10, "small") \
+	BENCH2(_label, _chars, 10000, "large")
+
+/* Iterate over character sets */
+#define BENCH_ALL() \
+	BENCH1("alpha", "abcdefghijklmnopqrstuvwxyz") \
+	BENCH1("escaped", "\"\\/\b\f\n\r\t") \
+	BENCH1("nonascii", "\xf0\xff")
+
+TEST_CASE("benchmark_serialize") {
+	BENCH_ALL()
+}

src/benchmark/benchmark_setup.h

@@ -0,0 +1,22 @@
+/*
+Minetest
+Copyright (C) 2022 Minetest Authors
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#define CATCH_CONFIG_ENABLE_BENCHMARKING
+#define CATCH_CONFIG_CONSOLE_WIDTH 160
+#include <catch.hpp>