| //===--- RandomShuffle.swift ----------------------------------------------===// |
| // |
| // This source file is part of the Swift.org open source project |
| // |
| // Copyright (c) 2018 Apple Inc. and the Swift project authors |
| // Licensed under Apache License v2.0 with Runtime Library Exception |
| // |
| // See https://swift.org/LICENSE.txt for license information |
| // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors |
| // |
| //===----------------------------------------------------------------------===// |
| |
| import TestsUtils |
| |
| // |
| // Benchmark that shuffles arrays of integers. Measures the performance of |
| // shuffling large arrays. |
| // |
| |
| public let RandomShuffle = [ |
| BenchmarkInfo(name: "RandomShuffleDef", runFunction: run_RandomShuffleDef, |
| tags: [.api], setUpFunction: setup_RandomShuffle), |
| BenchmarkInfo(name: "RandomShuffleLCG", runFunction: run_RandomShuffleLCG, |
| tags: [.api], setUpFunction: setup_RandomShuffle), |
| ] |
| |
| /// A linear congruential PRNG. |
| struct LCRNG: RandomNumberGenerator { |
| private var state: UInt64 |
| |
| init(seed: Int) { |
| state = UInt64(truncatingIfNeeded: seed) |
| for _ in 0..<10 { _ = next() } |
| } |
| |
| mutating func next() -> UInt64 { |
| state = 2862933555777941757 &* state &+ 3037000493 |
| return state |
| } |
| } |
| |
| var numbers = Array(0...3_000_000) |
| |
| @inline(never) |
| func setup_RandomShuffle() { |
| _ = numbers.count |
| } |
| |
| @inline(never) |
| public func run_RandomShuffleDef(_ N: Int) { |
| for _ in 0 ..< N { |
| numbers.shuffle() |
| blackHole(numbers.first!) |
| } |
| } |
| |
| @inline(never) |
| public func run_RandomShuffleLCG(_ N: Int) { |
| var generator = LCRNG(seed: 0) |
| for _ in 0 ..< N { |
| numbers.shuffle(using: &generator) |
| blackHole(numbers.first!) |
| } |
| } |