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// Copyright 2009 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.
// GOMAXPROCS=10 gotest
package sync_test
import (
"fmt"
"runtime"
. "sync"
"testing"
)
func parallelReader(m *RWMutex, clocked, cunlock, cdone chan bool) {
m.RLock()
clocked <- true
<-cunlock
m.RUnlock()
cdone <- true
}
func doTestParallelReaders(numReaders, gomaxprocs int) {
runtime.GOMAXPROCS(gomaxprocs)
var m RWMutex
clocked := make(chan bool)
cunlock := make(chan bool)
cdone := make(chan bool)
for i := 0; i < numReaders; i++ {
go parallelReader(&m, clocked, cunlock, cdone)
}
// Wait for all parallel RLock()s to succeed.
for i := 0; i < numReaders; i++ {
<-clocked
}
for i := 0; i < numReaders; i++ {
cunlock <- true
}
// Wait for the goroutines to finish.
for i := 0; i < numReaders; i++ {
<-cdone
}
}
func TestParallelReaders(t *testing.T) {
doTestParallelReaders(1, 4)
doTestParallelReaders(3, 4)
doTestParallelReaders(4, 2)
}
func reader(rwm *RWMutex, num_iterations int, activity *uint32, cdone chan bool) {
for i := 0; i < num_iterations; i++ {
rwm.RLock()
n := Xadd(activity, 1)
if n < 1 || n >= 10000 {
panic(fmt.Sprintf("wlock(%d)\n", n))
}
for i := 0; i < 100; i++ {
}
Xadd(activity, -1)
rwm.RUnlock()
}
cdone <- true
}
func writer(rwm *RWMutex, num_iterations int, activity *uint32, cdone chan bool) {
for i := 0; i < num_iterations; i++ {
rwm.Lock()
n := Xadd(activity, 10000)
if n != 10000 {
panic(fmt.Sprintf("wlock(%d)\n", n))
}
for i := 0; i < 100; i++ {
}
Xadd(activity, -10000)
rwm.Unlock()
}
cdone <- true
}
func HammerRWMutex(gomaxprocs, numReaders, num_iterations int) {
runtime.GOMAXPROCS(gomaxprocs)
// Number of active readers + 10000 * number of active writers.
var activity uint32
var rwm RWMutex
cdone := make(chan bool)
go writer(&rwm, num_iterations, &activity, cdone)
var i int
for i = 0; i < numReaders/2; i++ {
go reader(&rwm, num_iterations, &activity, cdone)
}
go writer(&rwm, num_iterations, &activity, cdone)
for ; i < numReaders; i++ {
go reader(&rwm, num_iterations, &activity, cdone)
}
// Wait for the 2 writers and all readers to finish.
for i := 0; i < 2+numReaders; i++ {
<-cdone
}
}
func TestRWMutex(t *testing.T) {
HammerRWMutex(1, 1, 1000)
HammerRWMutex(1, 3, 1000)
HammerRWMutex(1, 10, 1000)
HammerRWMutex(4, 1, 1000)
HammerRWMutex(4, 3, 1000)
HammerRWMutex(4, 10, 1000)
HammerRWMutex(10, 1, 1000)
HammerRWMutex(10, 3, 1000)
HammerRWMutex(10, 10, 1000)
HammerRWMutex(10, 5, 10000)
}
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