151 lines
3.8 KiB
Go
151 lines
3.8 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Copyright 2019 The gVisor Authors.
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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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// GOMAXPROCS=10 go test
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// Copy/pasted from the standard library's sync/rwmutex_test.go, except for the
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// addition of downgradingWriter and the renaming of num_iterations to
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// numIterations to shut up Golint.
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package syncutil
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import (
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"fmt"
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"runtime"
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"sync/atomic"
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"testing"
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)
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func parallelReader(m *DowngradableRWMutex, clocked, cunlock, cdone chan bool) {
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m.RLock()
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clocked <- true
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<-cunlock
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m.RUnlock()
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cdone <- true
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}
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func doTestParallelReaders(numReaders, gomaxprocs int) {
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runtime.GOMAXPROCS(gomaxprocs)
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var m DowngradableRWMutex
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clocked := make(chan bool)
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cunlock := make(chan bool)
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cdone := make(chan bool)
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for i := 0; i < numReaders; i++ {
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go parallelReader(&m, clocked, cunlock, cdone)
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}
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// Wait for all parallel RLock()s to succeed.
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for i := 0; i < numReaders; i++ {
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<-clocked
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}
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for i := 0; i < numReaders; i++ {
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cunlock <- true
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}
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// Wait for the goroutines to finish.
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for i := 0; i < numReaders; i++ {
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<-cdone
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}
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}
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func TestParallelReaders(t *testing.T) {
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defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(-1))
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doTestParallelReaders(1, 4)
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doTestParallelReaders(3, 4)
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doTestParallelReaders(4, 2)
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}
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func reader(rwm *DowngradableRWMutex, numIterations int, activity *int32, cdone chan bool) {
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for i := 0; i < numIterations; i++ {
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rwm.RLock()
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n := atomic.AddInt32(activity, 1)
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if n < 1 || n >= 10000 {
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panic(fmt.Sprintf("wlock(%d)\n", n))
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}
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for i := 0; i < 100; i++ {
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}
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atomic.AddInt32(activity, -1)
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rwm.RUnlock()
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}
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cdone <- true
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}
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func writer(rwm *DowngradableRWMutex, numIterations int, activity *int32, cdone chan bool) {
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for i := 0; i < numIterations; i++ {
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rwm.Lock()
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n := atomic.AddInt32(activity, 10000)
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if n != 10000 {
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panic(fmt.Sprintf("wlock(%d)\n", n))
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}
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for i := 0; i < 100; i++ {
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}
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atomic.AddInt32(activity, -10000)
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rwm.Unlock()
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}
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cdone <- true
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}
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func downgradingWriter(rwm *DowngradableRWMutex, numIterations int, activity *int32, cdone chan bool) {
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for i := 0; i < numIterations; i++ {
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rwm.Lock()
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n := atomic.AddInt32(activity, 10000)
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if n != 10000 {
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panic(fmt.Sprintf("wlock(%d)\n", n))
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}
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for i := 0; i < 100; i++ {
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}
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atomic.AddInt32(activity, -10000)
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rwm.DowngradeLock()
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n = atomic.AddInt32(activity, 1)
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if n < 1 || n >= 10000 {
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panic(fmt.Sprintf("wlock(%d)\n", n))
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}
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for i := 0; i < 100; i++ {
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}
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n = atomic.AddInt32(activity, -1)
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rwm.RUnlock()
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}
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cdone <- true
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}
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func HammerDowngradableRWMutex(gomaxprocs, numReaders, numIterations int) {
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runtime.GOMAXPROCS(gomaxprocs)
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// Number of active readers + 10000 * number of active writers.
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var activity int32
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var rwm DowngradableRWMutex
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cdone := make(chan bool)
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go writer(&rwm, numIterations, &activity, cdone)
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go downgradingWriter(&rwm, numIterations, &activity, cdone)
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var i int
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for i = 0; i < numReaders/2; i++ {
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go reader(&rwm, numIterations, &activity, cdone)
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}
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go writer(&rwm, numIterations, &activity, cdone)
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go downgradingWriter(&rwm, numIterations, &activity, cdone)
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for ; i < numReaders; i++ {
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go reader(&rwm, numIterations, &activity, cdone)
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}
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// Wait for the 4 writers and all readers to finish.
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for i := 0; i < 4+numReaders; i++ {
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<-cdone
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}
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}
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func TestDowngradableRWMutex(t *testing.T) {
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defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(-1))
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n := 1000
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if testing.Short() {
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n = 5
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}
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HammerDowngradableRWMutex(1, 1, n)
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HammerDowngradableRWMutex(1, 3, n)
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HammerDowngradableRWMutex(1, 10, n)
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HammerDowngradableRWMutex(4, 1, n)
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HammerDowngradableRWMutex(4, 3, n)
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HammerDowngradableRWMutex(4, 10, n)
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HammerDowngradableRWMutex(10, 1, n)
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HammerDowngradableRWMutex(10, 3, n)
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HammerDowngradableRWMutex(10, 10, n)
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HammerDowngradableRWMutex(10, 5, n)
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}
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