Add Benchmarks for metrics

Benchmarks/Benchmarks/PrometheusBenchmarks/Benchmarks.swift

@@ -0,0 +1,97 @@
+// swift-tools-version:5.7
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftPrometheus open source project
+//
+// Copyright (c) 2018-2023 SwiftPrometheus project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftPrometheus project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import Benchmark
+import Prometheus
+
+let benchmarks = {
+    Benchmark.defaultConfiguration.maxDuration = .seconds(5)
+    Benchmark.defaultConfiguration.scalingFactor = .kilo
+
+    let registry = PrometheusCollectorRegistry()
+
+    func metricsDimensions(_ idx: Int) -> [(String, String)] {
+        [
+            ("job", "api_server_\(idx)"),
+            ("handler", "/api/handler_\(idx)"),
+            ("status_code", "200"),
+            ("version", "\(idx).0.0"),
+        ]
+    }
+
+    Benchmark("1 - Metrics: Counter benchmark") { benchmark in
+        let ctr = registry.makeCounter(name: "counter_1", labels: metricsDimensions(1))
+        benchmark.startMeasurement()
+        for _ in benchmark.scaledIterations {
+            blackHole(ctr.increment())
+        }
+    }
+
+    Benchmark("2 - Metrics: Gauge benchmark") { benchmark in
+        let gauge = registry.makeGauge(name: "gauge_1", labels: metricsDimensions(2))
+        benchmark.startMeasurement()
+        for _ in benchmark.scaledIterations {
+            blackHole(gauge.increment())
+        }
+    }
+
+    Benchmark("3 - Metrics: Histogram benchmark") { benchmark in
+        let histogram = registry.makeDurationHistogram(name: "histogram_1", labels: metricsDimensions(3),
+                                                       buckets: [
+                                                           .milliseconds(100),
+                                                           .milliseconds(250),
+                                                           .milliseconds(500),
+                                                           .seconds(1),
+                                                       ])
+        benchmark.startMeasurement()
+        for _ in benchmark.scaledIterations {
+            histogram.record(Duration.milliseconds(400))
+        }
+    }
+
+    Benchmark("4 - Metrics: export 5000 metrics", 
+              configuration: .init(scalingFactor: .one)) { benchmark in
+        let metricsCount = 5000
+
+        let registryExport = PrometheusCollectorRegistry()
+
+        var counterArray = [Counter]()
+        var gaugeArray = [Gauge]()
+        var buffer = [UInt8]()
+
+        let counterExportSize = 620_000
+        counterArray.reserveCapacity(metricsCount)
+        gaugeArray.reserveCapacity(metricsCount)
+        buffer.reserveCapacity(counterExportSize)
+
+        for i in 0..<(metricsCount / 2) {
+            let counter = registryExport.makeCounter(name: "http_requests_total", labels: metricsDimensions(i))
+            counter.increment()
+            counterArray.append(counter)
+
+            let gauge = registryExport.makeGauge(name: "export_gauge_\(i)", labels: metricsDimensions(i))
+            gauge.increment()
+            gaugeArray.append(gauge)
+        }
+
+        benchmark.startMeasurement()
+        for _ in benchmark.scaledIterations {
+            blackHole(registryExport.emit(into: &buffer))
+
+        }
+        benchmark.stopMeasurement()
+        buffer.removeAll(keepingCapacity: true)
+    }
+}

Benchmarks/Package.swift

@@ -0,0 +1,38 @@
+// swift-tools-version:5.7
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftPrometheus open source project
+//
+// Copyright (c) 2018-2023 SwiftPrometheus project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftPrometheus project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import PackageDescription
+
+let package = Package(
+    name: "benchmarks",
+    platforms: [
+        .macOS("13"),
+    ],
+    dependencies: [
+        .package(path: "../"),
+        .package(url: "https://github.com/ordo-one/package-benchmark.git", from: "1.11.2"),
+    ],
+    targets: [
+        .executableTarget(
+            name: "PrometheusBenchmarks",
+            dependencies: [
+                .product(name: "Benchmark", package: "package-benchmark"),
+                .product(name: "BenchmarkPlugin", package: "package-benchmark"),
+                .product(name: "Prometheus", package: "swift-prometheus"),
+            ],
+            path: "Benchmarks/PrometheusBenchmarks"
+        ),
+    ]
+)