Add Benchmarks for metrics

Benchmarks/.gitignore

@@ -0,0 +1,10 @@
+.DS_Store
+.build
+/.build
+/Packages
+xcuserdata/
+DerivedData/
+.swiftpm/configuration/registries.json
+.swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata
+.netrc
+.benchmarkBaselines/

Benchmarks/Benchmarks/PrometheusBenchmarks/Benchmarks.swift

@@ -0,0 +1,62 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 registry = PrometheusCollectorRegistry()
+
+public func makeLabels(_ idx: Int) -> [(String, String)] {
+    [
+        ("job", "api_server_\(idx)"),
+        ("handler", "/api/handler_\(idx)"),
+        ("status_code", "200"),
+        ("version", "\(idx).0.0"),
+    ]
+}
+
+let benchmarks = {
+    Benchmark.defaultConfiguration.maxDuration = .seconds(5)
+    Benchmark.defaultConfiguration.scalingFactor = .kilo
+    Benchmark.defaultConfiguration.metrics = [.mallocCountTotal]
+
+    Benchmark("Counter - setup and increment") { benchmark in
+        runCounterBench(benchmark.scaledIterations)
+    }
+
+    Benchmark("Counter - increment only") { benchmark, run in
+        for _ in benchmark.scaledIterations {
+            run()
+        }
+    } setup: {
+        setupCounterBench()
+    }
+
+    Benchmark("Gauge") { benchmark in
+        runGaugeBench(benchmark.scaledIterations)
+    }
+
+    Benchmark("DurationHistogram") { benchmark in
+        runDurationHistogramBench(benchmark.scaledIterations)
+    }
+
+    Benchmark("RegistryEmit - 5000 metrics",
+              configuration: .init(scalingFactor: .one)) { benchmark, run in
+        for _ in benchmark.scaledIterations {
+            run()
+        }
+    } setup: {
+        setupRegistryExport(numberOfMetrics: 5000)
+    }
+}

Benchmarks/Benchmarks/PrometheusBenchmarks/Counter.swift

@@ -0,0 +1,30 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+
+public func runCounterBench(_ iterations: Range<Int>) {
+    let ctr = registry.makeCounter(name: "counter_1", labels: makeLabels(1))
+    for _ in iterations {
+        blackHole(ctr.increment())
+    }
+}
+
+public func setupCounterBench() -> () -> Void {
+    let ctr = registry.makeCounter(name: "counter_2", labels: makeLabels(2))
+    return {
+        blackHole(ctr.increment())
+    }
+}

Benchmarks/Benchmarks/PrometheusBenchmarks/DurationHistogram.swift

@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+
+public func runDurationHistogramBench(_ iterations: Range<Int>) {
+    let histogram = registry.makeDurationHistogram(
+        name: "histogram_1",
+        labels: makeLabels(3),
+        buckets: [
+            .milliseconds(100),
+            .milliseconds(250),
+            .milliseconds(500),
+            .seconds(1),
+        ]
+    )
+    for _ in iterations {
+        blackHole(histogram.record(Duration.milliseconds(400)))
+    }
+}

Benchmarks/Benchmarks/PrometheusBenchmarks/Gauge.swift

@@ -0,0 +1,30 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+
+public func runGaugeBench(_ iterations: Range<Int>) {
+    let gauge = registry.makeGauge(name: "gauge_1", labels: makeLabels(2))
+    for _ in iterations {
+        blackHole(gauge.increment())
+    }
+}
+
+public func setupGaugeBench() -> () -> Void {
+    let gauge = registry.makeGauge(name: "gauge_1", labels: makeLabels(2))
+    return {
+        blackHole(gauge.increment())
+    }
+}

Benchmarks/Benchmarks/PrometheusBenchmarks/RegistryEmit.swift

@@ -0,0 +1,42 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+
+public func setupRegistryExport(numberOfMetrics: Int) -> () -> Void {
+    let registryExport = PrometheusCollectorRegistry()
+
+    var counterArray = [Counter]()
+    var gaugeArray = [Gauge]()
+    var buffer = [UInt8]()
+
+    let counterExportSize = 620_000
+    counterArray.reserveCapacity(numberOfMetrics)
+    gaugeArray.reserveCapacity(numberOfMetrics)
+    buffer.reserveCapacity(counterExportSize)
+
+    for i in 0..<(numberOfMetrics / 2) {
+        let counter = registryExport.makeCounter(name: "http_requests_total", labels: makeLabels(i))
+        counter.increment()
+        counterArray.append(counter)
+
+        let gauge = registryExport.makeGauge(name: "export_gauge_\(i)", labels: makeLabels(i))
+        gauge.increment()
+        gaugeArray.append(gauge)
+    }
+    return {
+        blackHole(registryExport.emit(into: &buffer))
+    }
+}

Benchmarks/Package.swift

@@ -0,0 +1,40 @@
+// 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(.v13),
+    ],
+    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: "Prometheus", package: "swift-prometheus"),
+            ],
+            path: "Benchmarks/PrometheusBenchmarks",
+            plugins: [
+                .plugin(name: "BenchmarkPlugin", package: "package-benchmark"),
+            ]
+        ),
+    ]
+)

Benchmarks/Thresholds/5.10/PrometheusBenchmarks.Counter_-_increment_only.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 0
+}

Benchmarks/Thresholds/5.10/PrometheusBenchmarks.Counter_-_setup_and_increment.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 1
+}

Benchmarks/Thresholds/5.10/PrometheusBenchmarks.DurationHistogram.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 2
+}

Benchmarks/Thresholds/5.10/PrometheusBenchmarks.Gauge.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 1
+}

Benchmarks/Thresholds/5.10/PrometheusBenchmarks.RegistryEmit_-_5000_metrics.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 0
+}

Benchmarks/Thresholds/5.7/PrometheusBenchmarks.Counter_-_increment_only.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 0
+}

Benchmarks/Thresholds/5.7/PrometheusBenchmarks.Counter_-_setup_and_increment.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 1
+}

Benchmarks/Thresholds/5.7/PrometheusBenchmarks.DurationHistogram.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 2
+}

Benchmarks/Thresholds/5.7/PrometheusBenchmarks.Gauge.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 1
+}

Benchmarks/Thresholds/5.7/PrometheusBenchmarks.RegistryEmit_-_5000_metrics.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 0
+}

Benchmarks/Thresholds/5.8/PrometheusBenchmarks.Counter_-_increment_only.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 0
+}

Benchmarks/Thresholds/5.8/PrometheusBenchmarks.Counter_-_setup_and_increment.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 1
+}

Benchmarks/Thresholds/5.8/PrometheusBenchmarks.DurationHistogram.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 2
+}

Benchmarks/Thresholds/5.8/PrometheusBenchmarks.Gauge.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 1
+}

Benchmarks/Thresholds/5.8/PrometheusBenchmarks.RegistryEmit_-_5000_metrics.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 0
+}

Benchmarks/Thresholds/5.9/PrometheusBenchmarks.Counter_-_increment_only.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 0
+}

Benchmarks/Thresholds/5.9/PrometheusBenchmarks.Counter_-_setup_and_increment.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 1
+}

Benchmarks/Thresholds/5.9/PrometheusBenchmarks.DurationHistogram.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 2
+}

Benchmarks/Thresholds/5.9/PrometheusBenchmarks.Gauge.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 1
+}

Benchmarks/Thresholds/5.9/PrometheusBenchmarks.RegistryEmit_-_5000_metrics.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 0
+}

Benchmarks/Thresholds/main/PrometheusBenchmarks.Counter_-_increment_only.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 0
+}

Benchmarks/Thresholds/main/PrometheusBenchmarks.Counter_-_setup_and_increment.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 1
+}

Benchmarks/Thresholds/main/PrometheusBenchmarks.DurationHistogram.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 2
+}

Benchmarks/Thresholds/main/PrometheusBenchmarks.Gauge.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 1
+}

Benchmarks/Thresholds/main/PrometheusBenchmarks.RegistryEmit_-_5000_metrics.p90.json

@@ -0,0 +1,3 @@
+{
+  "mallocCountTotal" : 0
+}

README.md

@@ -22,3 +22,17 @@ If you find a bug or have issues, please [create an issue](https://github.com/sw
 
 [Documentation]: https://swiftpackageindex.com/swift-server/swift-prometheus/documentation/prometheus
 [SSWG-Incubation]: https://www.swift.org/sswg/incubation-process.html
+
+
+## Benchmarks
+
+Benchmarks for `swift-prometheus` are in a separate Swift Package in the `Benchmarks` subfolder of this repository.
+They use the [`package-benchmark`](https://github.com/ordo-one/package-benchmark) plugin.
+Benchmarks depends on the [`jemalloc`](https://jemalloc.net) memory allocation library, which is used by `package-benchmark` to capture memory allocation statistics.
+An installation guide can be found in the [Getting Started article](https://swiftpackageindex.com/ordo-one/package-benchmark/documentation/benchmark/gettingstarted#Installing-Prerequisites-and-Platform-Support) of `package-benchmark`.
+Afterwards you can run the benchmarks from CLI by going to the `Benchmarks` subfolder (e.g. `cd Benchmarks`) and invoking:
+```
+swift package benchmark
+```
+
+For more information please refer to `swift package benchmark --help` or the [documentation of `package-benchmark`](https://swiftpackageindex.com/ordo-one/package-benchmark/documentation/benchmark).