mirror of git://gcc.gnu.org/git/gcc.git
				
				
				
			
		
			
				
	
	
		
			141 lines
		
	
	
		
			2.8 KiB
		
	
	
	
		
			Go
		
	
	
	
			
		
		
	
	
			141 lines
		
	
	
		
			2.8 KiB
		
	
	
	
		
			Go
		
	
	
	
// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package runtime_test
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import (
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	"math/rand"
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	. "runtime"
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	"testing"
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	"unsafe"
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)
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type MyNode struct {
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	LFNode
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	data int
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}
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func fromMyNode(node *MyNode) *LFNode {
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	return (*LFNode)(unsafe.Pointer(node))
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}
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func toMyNode(node *LFNode) *MyNode {
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	return (*MyNode)(unsafe.Pointer(node))
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}
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var global interface{}
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func TestLFStack(t *testing.T) {
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	stack := new(uint64)
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	global = stack // force heap allocation
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	// Need to keep additional references to nodes, the stack is not all that type-safe.
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	var nodes []*MyNode
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	// Check the stack is initially empty.
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	if LFStackPop(stack) != nil {
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		t.Fatalf("stack is not empty")
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	}
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	// Push one element.
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	node := &MyNode{data: 42}
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	nodes = append(nodes, node)
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	LFStackPush(stack, fromMyNode(node))
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	// Push another.
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	node = &MyNode{data: 43}
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	nodes = append(nodes, node)
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	LFStackPush(stack, fromMyNode(node))
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	// Pop one element.
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	node = toMyNode(LFStackPop(stack))
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	if node == nil {
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		t.Fatalf("stack is empty")
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	}
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	if node.data != 43 {
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		t.Fatalf("no lifo")
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	}
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	// Pop another.
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	node = toMyNode(LFStackPop(stack))
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	if node == nil {
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		t.Fatalf("stack is empty")
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	}
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	if node.data != 42 {
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		t.Fatalf("no lifo")
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	}
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	// Check the stack is empty again.
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	if LFStackPop(stack) != nil {
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		t.Fatalf("stack is not empty")
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	}
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	if *stack != 0 {
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		t.Fatalf("stack is not empty")
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	}
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}
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var stress []*MyNode
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func TestLFStackStress(t *testing.T) {
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	const K = 100
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	P := 4 * GOMAXPROCS(-1)
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	N := 100000
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	if testing.Short() {
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		N /= 10
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	}
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	// Create 2 stacks.
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	stacks := [2]*uint64{new(uint64), new(uint64)}
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	// Need to keep additional references to nodes,
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	// the lock-free stack is not type-safe.
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	stress = nil
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	// Push K elements randomly onto the stacks.
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	sum := 0
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	for i := 0; i < K; i++ {
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		sum += i
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		node := &MyNode{data: i}
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		stress = append(stress, node)
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		LFStackPush(stacks[i%2], fromMyNode(node))
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	}
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	c := make(chan bool, P)
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	for p := 0; p < P; p++ {
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		go func() {
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			r := rand.New(rand.NewSource(rand.Int63()))
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			// Pop a node from a random stack, then push it onto a random stack.
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			for i := 0; i < N; i++ {
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				node := toMyNode(LFStackPop(stacks[r.Intn(2)]))
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				if node != nil {
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					LFStackPush(stacks[r.Intn(2)], fromMyNode(node))
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				}
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			}
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			c <- true
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		}()
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	}
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	for i := 0; i < P; i++ {
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		<-c
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	}
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	// Pop all elements from both stacks, and verify that nothing lost.
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	sum2 := 0
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	cnt := 0
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	for i := 0; i < 2; i++ {
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		for {
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			node := toMyNode(LFStackPop(stacks[i]))
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			if node == nil {
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				break
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			}
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			cnt++
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			sum2 += node.data
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			node.Next = 0
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		}
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	}
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	if cnt != K {
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		t.Fatalf("Wrong number of nodes %d/%d", cnt, K)
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	}
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	if sum2 != sum {
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		t.Fatalf("Wrong sum %d/%d", sum2, sum)
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	}
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	// Let nodes be collected now.
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	stress = nil
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}
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