Squashed 'libs/loguru/' content from commit 644f60d

git-subtree-dir: libs/loguru
git-subtree-split: 644f60dca77de3b0f718a03d370c8ebdf5f97968

loguru_bench/loguru_bench.cpp

@@ -0,0 +1,121 @@
+#include <chrono>
+#include <cmath>
+#include <iomanip>
+#include <iostream>
+#include <vector>
+
+#define LOGURU_WITH_STREAMS 1
+#define LOGURU_REDEFINE_ASSERT 1
+#include "../loguru.cpp"
+
+const size_t kNumRuns = 10;
+const double kPi = 3.1415926535897932384626433;
+
+static long long now_ns()
+{
+	using namespace std::chrono;
+	return duration_cast<nanoseconds>(high_resolution_clock::now().time_since_epoch()).count();
+}
+
+template<typename Function>
+void bench(const std::string& name, const Function& function, size_t num_iterations)
+{
+	function(num_iterations); // Warm-up.
+
+	printf("%-30s ", name.c_str());
+	fflush(stdout);
+	std::vector<double> times;
+	double sum = 0;
+	for (size_t i = 0; i < kNumRuns; ++i) {
+		auto start_ns = now_ns();
+		function(num_iterations);
+		double total_time_sec = (now_ns() - start_ns) * 1e-9;
+		times.push_back(total_time_sec / num_iterations);
+		sum += times.back();
+	}
+
+	double mean = sum / kNumRuns;
+	double std_dev_sum = 0;
+
+	for (double time : times) {
+		std_dev_sum += (time - mean) * (time - mean);
+	}
+
+	double variance = std::sqrt(std_dev_sum / kNumRuns);
+
+	printf("%6.3f ± %.3f μs per call\n", mean * 1e6, variance * 1e6);
+	fflush(stdout);
+}
+
+// ----------------------------------------------------------------------------
+
+void format_strings(size_t num_iterations)
+{
+	for (size_t i = 0; i < num_iterations; ++i) {
+		LOG_F(WARNING, "Some long, complex message.");
+	}
+	loguru::flush();
+}
+
+void format_float(size_t num_iterations)
+{
+	for (size_t i = 0; i < num_iterations; ++i) {
+		LOG_F(WARNING, "%+05.3f", kPi);
+	}
+	loguru::flush();
+}
+
+void stream_strings(size_t num_iterations)
+{
+	for (size_t i = 0; i < num_iterations; ++i) {
+		LOG_S(WARNING) << "Some long, complex message.";
+	}
+	loguru::flush();
+}
+
+void stream_float(size_t num_iterations)
+{
+	for (size_t i = 0; i < num_iterations; ++i) {
+		LOG_S(WARNING) << std::setfill('0') << std::setw(5) << std::setprecision(3) << kPi;
+	}
+	loguru::flush();
+}
+
+void raw_string_float(size_t num_iterations)
+{
+	for (size_t i = 0; i < num_iterations; ++i) {
+		RAW_LOG_F(WARNING, "Some long, complex message.");
+	}
+	loguru::flush();
+}
+
+void error_context(size_t num_iterations)
+{
+	for (size_t i = 0; i < num_iterations; ++i) {
+		ERROR_CONTEXT("key", "value");
+	}
+}
+
+int main(int argc, char* argv[])
+{
+	const size_t kNumIterations = 50 * 1000;
+
+	loguru::init(argc, argv);
+	loguru::add_file("loguru_bench.log", loguru::Truncate, loguru::Verbosity_INFO);
+
+	bench("ERROR_CONTEXT", error_context, kNumIterations * 100);
+
+	loguru::g_flush_interval_ms = 200;
+	bench("LOG_F string (buffered):", format_strings,   kNumIterations);
+	bench("LOG_F float  (buffered):", format_float,     kNumIterations);
+	bench("LOG_S string (buffered):", stream_strings,   kNumIterations);
+	bench("LOG_S float  (buffered):", stream_float,     kNumIterations);
+	bench("RAW_LOG_F    (buffered):", raw_string_float, kNumIterations);
+
+	loguru::g_flush_interval_ms = 0;
+	bench("LOG_F string (unbuffered):", format_strings,   kNumIterations);
+	bench("LOG_F float  (unbuffered):", format_float,     kNumIterations);
+	bench("LOG_S string (unbuffered):", stream_strings,   kNumIterations);
+	bench("LOG_S float  (unbuffered):", stream_float,     kNumIterations);
+	bench("RAW_LOG_F    (unbuffered):", raw_string_float, kNumIterations);
+}