feat: [sc-858]: Move Benchmark to DateTime package (#4)

* Adding BenchmarkClock and nanoseconds convenience accessor for Duration.

Benchmarks/Clocks/Clocks.swift

@@ -15,7 +15,7 @@ import BenchmarkSupport
 func benchmarks() {
 
     Benchmark.defaultDesiredDuration = .seconds(2)
-    Benchmark.defaultDesiredIterations = 1_000
+    Benchmark.defaultDesiredIterations = 10_000
     Benchmark.defaultThroughputScalingFactor = .kilo
 
     Benchmark("InternalUTCClock.now") { benchmark in
@@ -24,6 +24,12 @@ func benchmarks() {
         }
     }
 
+    Benchmark("BenchmarkClock.now") { benchmark in
+        for _ in 0 ..< benchmark.throughputScalingFactor.rawValue {
+            BenchmarkSupport.blackHole(BenchmarkClock.now)
+        }
+    }
+
     Benchmark("Foundation.Date") { benchmark in
         for _ in 0 ..< benchmark.throughputScalingFactor.rawValue {
             BenchmarkSupport.blackHole(Foundation.Date())

Sources/DateTime/BenchmarkClock.swift

@@ -0,0 +1,178 @@
+// Copyright 2002 Ordo One AB
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+
+// An implementation of a clock suitable for benchmarking using clock_gettime_nsec_np() on macOS
+// which is ~2-3 x less overhead.
+
+// swiftlint:disable line_length identifier_name
+
+// Largely adopted by Swift's ContinuousClock
+// https://github.com/apple/swift/blob/48987de3d3ab228eed4867949795c188759df234/stdlib/public/Concurrency/ContinuousClock.swift#L49
+
+#if canImport(Darwin)
+import Darwin
+#elseif canImport(Glibc)
+import Glibc
+#else
+#error("Unsupported Platform")
+#endif
+
+public struct BenchmarkClock {
+    /// A continuous point in time used for `BenchmarkClock`.
+    public struct Instant: Codable, Sendable {
+        internal var _value: Swift.Duration
+
+        internal init(_value: Swift.Duration) {
+            self._value = _value
+        }
+    }
+
+    public init() {}
+}
+
+public extension Clock where Self == BenchmarkClock {
+    /// A clock that measures time that always increments but does not stop
+    /// incrementing while the system is asleep.
+    ///
+    ///       try await Task.sleep(until: .now + .seconds(3), clock: .continuous)
+    ///
+    static var internalUTC: BenchmarkClock { return BenchmarkClock() }
+}
+
+extension BenchmarkClock: Clock {
+    /// The current continuous instant.
+    public var now: BenchmarkClock.Instant {
+        BenchmarkClock.now
+    }
+
+    /// The minimum non-zero resolution between any two calls to `now`.
+    public var minimumResolution: Swift.Duration {
+#if os(macOS)
+        return Duration.nanoseconds(1)
+#elseif os(Linux)
+        var resolution = timespec()
+
+        let result = clock_getres(CLOCK_REALTIME, &resolution)
+
+        guard result == 0 else {
+            fatalError("Failed to get realtime clock resolution in clock_getres(), errno = \(errno)")
+        }
+
+        let seconds = Int64(resolution.tv_sec)
+        let attoseconds = Int64(resolution.tv_nsec) * 1_000_000_000
+
+        return Duration(secondsComponent: seconds, attosecondsComponent: attoseconds)
+#else
+#error("Unsupported Platform")
+#endif
+    }
+
+    /// The current continuous instant.
+    public static var now: BenchmarkClock.Instant {
+#if os(macOS)
+        let nanos = clock_gettime_nsec_np(CLOCK_UPTIME_RAW) // to get ns resolution on macOS
+
+        let seconds: UInt64 = nanos / 1_000_000_000
+        let attoseconds: UInt64 = (nanos % 1_000_000_000) * 1_000_000_000
+        return BenchmarkClock.Instant(_value: Duration(secondsComponent: Int64(seconds),
+                                                       attosecondsComponent: Int64(attoseconds)))
+#elseif os(Linux)
+        var timespec = timespec()
+        let result = clock_gettime(CLOCK_REALTIME, &timespec)
+
+        guard result == 0 else {
+            fatalError("Failed to get current time in clock_gettime(), errno = \(errno)")
+        }
+        let seconds = Int64(timespec.tv_sec)
+        let attoseconds = Int64(timespec.tv_nsec) * 1_000_000_000
+
+        return BenchmarkClock.Instant(_value: Duration(secondsComponent: Int64(seconds),
+                                                       attosecondsComponent: Int64(attoseconds)))
+#else
+#error("Unsupported Platform")
+#endif
+    }
+
+    /// Suspend task execution until a given deadline within a tolerance.
+    /// If no tolerance is specified then the system may adjust the deadline
+    /// to coalesce CPU wake-ups to more efficiently process the wake-ups in
+    /// a more power efficient manner.
+    ///
+    /// If the task is canceled before the time ends, this function throws
+    /// `CancellationError`.
+    ///
+    /// This function doesn't block the underlying thread.
+    public func sleep(
+        until deadline: Instant, tolerance: Swift.Duration? = nil
+    ) async throws {
+        try await Task.sleep(until: deadline, tolerance: tolerance, clock: .internalUTC)
+    }
+}
+
+extension BenchmarkClock.Instant: InstantProtocol {
+    public static var now: BenchmarkClock.Instant { BenchmarkClock.now }
+
+    public func advanced(by duration: Swift.Duration) -> BenchmarkClock.Instant {
+        return BenchmarkClock.Instant(_value: _value + duration)
+    }
+
+    public func duration(to other: BenchmarkClock.Instant) -> Swift.Duration {
+        other._value - _value
+    }
+
+    public func hash(into hasher: inout Hasher) {
+        hasher.combine(_value)
+    }
+
+    public static func == (
+        _ lhs: BenchmarkClock.Instant, _ rhs: BenchmarkClock.Instant
+    ) -> Bool {
+        return lhs._value == rhs._value
+    }
+
+    public static func < (
+        _ lhs: BenchmarkClock.Instant, _ rhs: BenchmarkClock.Instant
+    ) -> Bool {
+        return lhs._value < rhs._value
+    }
+
+    @inlinable
+    public static func + (
+        _ lhs: BenchmarkClock.Instant, _ rhs: Swift.Duration
+    ) -> BenchmarkClock.Instant {
+        lhs.advanced(by: rhs)
+    }
+
+    @inlinable
+    public static func += (
+        _ lhs: inout BenchmarkClock.Instant, _ rhs: Swift.Duration
+    ) {
+        lhs = lhs.advanced(by: rhs)
+    }
+
+    @inlinable
+    public static func - (
+        _ lhs: BenchmarkClock.Instant, _ rhs: Swift.Duration
+    ) -> BenchmarkClock.Instant {
+        lhs.advanced(by: .zero - rhs)
+    }
+
+    @inlinable
+    public static func -= (
+        _ lhs: inout BenchmarkClock.Instant, _ rhs: Swift.Duration
+    ) {
+        lhs = lhs.advanced(by: .zero - rhs)
+    }
+
+    @inlinable
+    public static func - (
+        _ lhs: BenchmarkClock.Instant, _ rhs: BenchmarkClock.Instant
+    ) -> Swift.Duration {
+        rhs.duration(to: lhs)
+    }
+}

Sources/DateTime/Convenience.swift

@@ -0,0 +1,5 @@
+public extension Duration {
+    func nanoseconds() -> Int64 {
+        return (self.components.seconds * 1_000_000_000) + (self.components.attoseconds / 1_000_000_000)
+    }
+}

Tests/DateTimeTests/DateTime.swift

@@ -12,15 +12,30 @@ import XCTest
 final class DateTimeTests: XCTestCase {
     func testExample() throws {
         let time = InternalUTCClock().measure {
-            print("Time now: \(InternalUTCClock.now)")
-            print("Time now: \(InternalUTCClock.now._value.components)")
-            print("Resolution: \(InternalUTCClock().minimumResolution)")
+            print("InternalUTCClock Time now: \(InternalUTCClock.now)")
+            print("InternalUTCClock Time now: \(InternalUTCClock.now._value.components)")
+            print("InternalUTCClock Resolution: \(InternalUTCClock().minimumResolution)")
         }
-        print("Elapsed time in nanoseconds \(time.components.attoseconds / 1_000_000_000)")
+        print("InternalUTCClock Elapsed time in nanoseconds \(time.components.attoseconds / 1_000_000_000)")
         let time2 = InternalUTCClock().measure {
             _ = 47
         }
-        print("Elapsed time in nanoseconds for empty closure \(time2.components.attoseconds / 1_000_000_000)")
+        print("InternalUTCClock Elapsed time in nanoseconds for empty closure \(time2.components.attoseconds / 1_000_000_000)")
+        // This is an example of a functional test case.
+        // Use XCTAssert and related functions to verify your tests produce the correct
+        // results.
+    }
+    func testBenchmarkClock() throws {
+        let time = BenchmarkClock().measure {
+            print("BenchmarkClock Time now: \(BenchmarkClock.now)")
+            print("BenchmarkClock Time now: \(BenchmarkClock.now._value.components)")
+            print("BenchmarkClock Resolution: \(BenchmarkClock().minimumResolution)")
+        }
+        print("BenchmarkClock Elapsed time in nanoseconds \(time.components.attoseconds / 1_000_000_000)")
+        let time2 = BenchmarkClock().measure {
+            _ = 47
+        }
+        print("BenchmarkClock Elapsed time in nanoseconds for empty closure \(time2.components.attoseconds / 1_000_000_000)")
         // This is an example of a functional test case.
         // Use XCTAssert and related functions to verify your tests produce the correct
         // results.