parfor_test.go 3.06 KB
Newer Older
1 2 3 4
// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

5 6 7
// The race detector does not understand ParFor synchronization.
// +build !race

8 9 10 11 12 13 14 15
package runtime_test

import (
	. "runtime"
	"testing"
	"unsafe"
)

16 17
var gdata []uint64

18 19 20 21 22 23 24 25 26
// Simple serial sanity test for parallelfor.
func TestParFor(t *testing.T) {
	const P = 1
	const N = 20
	data := make([]uint64, N)
	for i := uint64(0); i < N; i++ {
		data[i] = i
	}
	desc := NewParFor(P)
27 28 29 30
	// Avoid making func a closure: parfor cannot invoke them.
	// Since it doesn't happen in the C code, it's not worth doing
	// just for the test.
	gdata = data
31
	ParForSetup(desc, P, N, nil, true, func(desc *ParFor, i uint32) {
32
		data := gdata
33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113
		data[i] = data[i]*data[i] + 1
	})
	ParForDo(desc)
	for i := uint64(0); i < N; i++ {
		if data[i] != i*i+1 {
			t.Fatalf("Wrong element %d: %d", i, data[i])
		}
	}
}

// Test that nonblocking parallelfor does not block.
func TestParFor2(t *testing.T) {
	const P = 7
	const N = 1003
	data := make([]uint64, N)
	for i := uint64(0); i < N; i++ {
		data[i] = i
	}
	desc := NewParFor(P)
	ParForSetup(desc, P, N, (*byte)(unsafe.Pointer(&data)), false, func(desc *ParFor, i uint32) {
		d := *(*[]uint64)(unsafe.Pointer(desc.Ctx))
		d[i] = d[i]*d[i] + 1
	})
	for p := 0; p < P; p++ {
		ParForDo(desc)
	}
	for i := uint64(0); i < N; i++ {
		if data[i] != i*i+1 {
			t.Fatalf("Wrong element %d: %d", i, data[i])
		}
	}
}

// Test that iterations are properly distributed.
func TestParForSetup(t *testing.T) {
	const P = 11
	const N = 101
	desc := NewParFor(P)
	for n := uint32(0); n < N; n++ {
		for p := uint32(1); p <= P; p++ {
			ParForSetup(desc, p, n, nil, true, func(desc *ParFor, i uint32) {})
			sum := uint32(0)
			size0 := uint32(0)
			end0 := uint32(0)
			for i := uint32(0); i < p; i++ {
				begin, end := ParForIters(desc, i)
				size := end - begin
				sum += size
				if i == 0 {
					size0 = size
					if begin != 0 {
						t.Fatalf("incorrect begin: %d (n=%d, p=%d)", begin, n, p)
					}
				} else {
					if size != size0 && size != size0+1 {
						t.Fatalf("incorrect size: %d/%d (n=%d, p=%d)", size, size0, n, p)
					}
					if begin != end0 {
						t.Fatalf("incorrect begin/end: %d/%d (n=%d, p=%d)", begin, end0, n, p)
					}
				}
				end0 = end
			}
			if sum != n {
				t.Fatalf("incorrect sum: %d/%d (p=%d)", sum, n, p)
			}
		}
	}
}

// Test parallel parallelfor.
func TestParForParallel(t *testing.T) {
	N := uint64(1e7)
	if testing.Short() {
		N /= 10
	}
	data := make([]uint64, N)
	for i := uint64(0); i < N; i++ {
		data[i] = i
	}
	P := GOMAXPROCS(-1)
114
	c := make(chan bool, P)
115
	desc := NewParFor(uint32(P))
116
	gdata = data
117
	ParForSetup(desc, uint32(P), uint32(N), nil, false, func(desc *ParFor, i uint32) {
118
		data := gdata
119 120 121
		data[i] = data[i]*data[i] + 1
	})
	for p := 1; p < P; p++ {
122 123 124 125
		go func() {
			ParForDo(desc)
			c <- true
		}()
126 127
	}
	ParForDo(desc)
128 129 130
	for p := 1; p < P; p++ {
		<-c
	}
131 132 133 134 135
	for i := uint64(0); i < N; i++ {
		if data[i] != i*i+1 {
			t.Fatalf("Wrong element %d: %d", i, data[i])
		}
	}
136 137 138

	data, desc = nil, nil
	GC()
139
}