[interop] rewrite the C++ vector sum benchmark to have clear naming and take iter into account

Author: hyp

benchmark/cxx-source/CxxVectorSum.swift

@@ -19,54 +19,94 @@ import Cxx
 
 public let benchmarks = [
   BenchmarkInfo(
-      name: "CxxVectorOfU32SumInCxx",
-      runFunction: run_CxxVectorOfU32SumInCxx,
-      tags: [.validation, .bridging, .cxxInterop],
-      setUpFunction: create_CxxVectorOfU32),
+      name: "CxxVectorOfU32.Sum.Cxx.RangedForLoop",
+      runFunction: run_CxxVectorOfU32_Sum_Cxx_RangedForLoop,
+      tags: [.validation, .bridging, .cxxInterop]),
   BenchmarkInfo(
-    name: "CxxVectorOfU32SumInSwift_Fastest",
-    runFunction: run_CxxVectorOfU32SumInSwift_Fastest,
-    tags: [.validation, .bridging, .cxxInterop],
-    setUpFunction: create_CxxVectorOfU32),
+    name: "CxxVectorOfU32.Sum.Swift.ForInLoop",
+    runFunction: run_CxxVectorOfU32_Sum_Swift_ForInLoop,
+    tags: [.validation, .bridging, .cxxInterop]),
   BenchmarkInfo(
-    name: "CxxVectorOfU32SumInSwift",
-    runFunction: run_CxxVectorOfU32SumInSwift,
-    tags: [.validation, .bridging, .cxxInterop],
-    setUpFunction: create_CxxVectorOfU32)
+    name: "CxxVectorOfU32.Sum.Swift.RawIteratorLoop",
+    runFunction: run_CxxVectorOfU32_Sum_Swift_RawIteratorLoop,
+    tags: [.validation, .bridging, .cxxInterop]),
+  BenchmarkInfo(
+    name: "CxxVectorOfU32.Sum.Swift.IndexAndSubscriptLoop",
+    runFunction: run_CxxVectorOfU32_Sum_Swift_IndexAndSubscriptLoop,
+    tags: [.validation, .bridging, .cxxInterop]),
+  BenchmarkInfo(
+    name: "CxxVectorOfU32.Sum.Swift.Reduce",
+    runFunction: run_CxxVectorOfU32_Sum_Swift_Reduce,
+    tags: [.validation, .bridging, .cxxInterop])
 ]
 
 // FIXME: compare CxxVectorOfU32SumInCxx to CxxVectorOfU32SumInSwift and
 // establish an expected threshold of performance, which when exceeded should
 // fail the benchmark.
 
-var vectorOfU32: VectorOfU32!
+let vectorSize = 100_000
+let iterRepeatFactor = 10
 
-func create_CxxVectorOfU32() {
-    vectorOfU32 = makeVector32(1_000_000)
+@inline(never)
+public func run_CxxVectorOfU32_Sum_Cxx_RangedForLoop(_ n: Int) {
+  let sum = testVector32Sum(vectorSize, n * iterRepeatFactor)
+  blackHole(sum)
 }
 
 @inline(never)
-public func run_CxxVectorOfU32SumInCxx(_ n: Int) {
-  // FIXME: Use no implicitly copyable, immutable borrow instead.
-  // https://github.com/apple/swift/issues/61454
-  let sum = testVector32Sum(&vectorOfU32)
+public func run_CxxVectorOfU32_Sum_Swift_ForInLoop(_ n: Int) {
+    let vectorOfU32 = makeVector32(vectorSize)
+    var sum: UInt32 = 0
+    for _ in 0..<(n * iterRepeatFactor) {
+      for x in vectorOfU32 {
+        sum = sum &+ x
+      }
+    }
+    blackHole(sum)
+}
+
+// This function should have comparable performance to
+// `run_CxxVectorOfU32_Sum_Cxx_RangedForLoop`.
+@inline(never)
+public func run_CxxVectorOfU32_Sum_Swift_RawIteratorLoop(_ n: Int) {
+  let vectorOfU32 = makeVector32(vectorSize)
+  var sum: UInt32 = 0
+  for _ in 0..<(n * iterRepeatFactor) {
+    var b = vectorOfU32.__beginUnsafe()
+    let e = vectorOfU32.__endUnsafe()
+    while !cmp(b, e) {
+        sum = sum &+ b.pointee
+        b = next(b)
+    }
+  }
   blackHole(sum)
 }
 
-// This function should have comparable performance to `run_CxxVectorOfU32SumInCxx`.
 @inline(never)
-public func run_CxxVectorOfU32SumInSwift_Fastest(_ n: Int) {
+public func run_CxxVectorOfU32_Sum_Swift_IndexAndSubscriptLoop(_ n: Int) {
+  let vectorOfU32 = makeVector32(vectorSize)
   var sum: UInt32 = 0
-  // begin mutating, end mutating needed to avoid copies right now.
-  var b = vectorOfU32.beginMutating()
-  let e = vectorOfU32.endMutating()
-  while !cmp(b, e) {
-    sum = sum &+ b.pointee
-    b = next(b)
+  for _ in 0..<(n * iterRepeatFactor) {
+    var i = 0
+    let e = vectorOfU32.size()
+    while i != e {
+        sum = sum &+ vectorOfU32[i]
+        i = i &+ 1
+    }
   }
   blackHole(sum)
 }
 
+@inline(never)
+public func run_CxxVectorOfU32_Sum_Swift_Reduce(_ n: Int) {
+    let vectorOfU32 = makeVector32(vectorSize)
+    var sum: UInt32 = 0
+    for _ in 0..<(n * iterRepeatFactor) {
+      sum = vectorOfU32.reduce(sum, &+)
+    }
+    blackHole(sum)
+}
+
 public func !=(_ y: VectorOfU32.const_iterator, _ x: VectorOfU32.const_iterator) -> Bool {
     return y.__baseUnsafe() != x.__baseUnsafe()
 }
@@ -78,12 +118,3 @@ public func ==(_ y: VectorOfU32.const_iterator, _ x: VectorOfU32.const_iterator)
 extension VectorOfU32.const_iterator : Equatable, UnsafeCxxInputIterator { }
 
 extension VectorOfU32: CxxSequence {}
-
-@inline(never)
-public func run_CxxVectorOfU32SumInSwift(_ n: Int) {
-    var sum: UInt32 = 0
-    for i in vectorOfU32 {
-        sum = sum &+ i
-    }
-    blackHole(sum)
-}

benchmark/utils/CxxTests/CxxStdlibPerformance.h

@@ -14,10 +14,13 @@ inline VectorOfU32 makeVector32(size_t size) {
     return result;
 }
 
-inline uint32_t testVector32Sum(VectorOfU32 &vector) {
+inline uint32_t testVector32Sum(size_t vectorSize, size_t iters) {
+    auto vector = makeVector32(vectorSize);
     auto sum = uint32_t(0);
-    for (auto i : vector) {
-        sum += i;
+    for (size_t i = 0; i < iters; ++i) {
+        for (auto x : vector) {
+            sum += x;
+        }
     }
     return sum;
 }