mirror of
https://github.com/restic/restic.git
synced 2024-08-30 08:07:23 +02:00
172 lines
3.5 KiB
Go
172 lines
3.5 KiB
Go
// Copyright 2017 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.
|
|
|
|
package semaphore_test
|
|
|
|
import (
|
|
"math/rand"
|
|
"runtime"
|
|
"sync"
|
|
"testing"
|
|
"time"
|
|
|
|
"golang.org/x/net/context"
|
|
"golang.org/x/sync/errgroup"
|
|
"golang.org/x/sync/semaphore"
|
|
)
|
|
|
|
const maxSleep = 1 * time.Millisecond
|
|
|
|
func HammerWeighted(sem *semaphore.Weighted, n int64, loops int) {
|
|
for i := 0; i < loops; i++ {
|
|
sem.Acquire(context.Background(), n)
|
|
time.Sleep(time.Duration(rand.Int63n(int64(maxSleep/time.Nanosecond))) * time.Nanosecond)
|
|
sem.Release(n)
|
|
}
|
|
}
|
|
|
|
func TestWeighted(t *testing.T) {
|
|
t.Parallel()
|
|
|
|
n := runtime.GOMAXPROCS(0)
|
|
loops := 10000 / n
|
|
sem := semaphore.NewWeighted(int64(n))
|
|
var wg sync.WaitGroup
|
|
wg.Add(n)
|
|
for i := 0; i < n; i++ {
|
|
i := i
|
|
go func() {
|
|
defer wg.Done()
|
|
HammerWeighted(sem, int64(i), loops)
|
|
}()
|
|
}
|
|
wg.Wait()
|
|
}
|
|
|
|
func TestWeightedPanic(t *testing.T) {
|
|
t.Parallel()
|
|
|
|
defer func() {
|
|
if recover() == nil {
|
|
t.Fatal("release of an unacquired weighted semaphore did not panic")
|
|
}
|
|
}()
|
|
w := semaphore.NewWeighted(1)
|
|
w.Release(1)
|
|
}
|
|
|
|
func TestWeightedTryAcquire(t *testing.T) {
|
|
t.Parallel()
|
|
|
|
ctx := context.Background()
|
|
sem := semaphore.NewWeighted(2)
|
|
tries := []bool{}
|
|
sem.Acquire(ctx, 1)
|
|
tries = append(tries, sem.TryAcquire(1))
|
|
tries = append(tries, sem.TryAcquire(1))
|
|
|
|
sem.Release(2)
|
|
|
|
tries = append(tries, sem.TryAcquire(1))
|
|
sem.Acquire(ctx, 1)
|
|
tries = append(tries, sem.TryAcquire(1))
|
|
|
|
want := []bool{true, false, true, false}
|
|
for i := range tries {
|
|
if tries[i] != want[i] {
|
|
t.Errorf("tries[%d]: got %t, want %t", i, tries[i], want[i])
|
|
}
|
|
}
|
|
}
|
|
|
|
func TestWeightedAcquire(t *testing.T) {
|
|
t.Parallel()
|
|
|
|
ctx := context.Background()
|
|
sem := semaphore.NewWeighted(2)
|
|
tryAcquire := func(n int64) bool {
|
|
ctx, cancel := context.WithTimeout(ctx, 10*time.Millisecond)
|
|
defer cancel()
|
|
return sem.Acquire(ctx, n) == nil
|
|
}
|
|
|
|
tries := []bool{}
|
|
sem.Acquire(ctx, 1)
|
|
tries = append(tries, tryAcquire(1))
|
|
tries = append(tries, tryAcquire(1))
|
|
|
|
sem.Release(2)
|
|
|
|
tries = append(tries, tryAcquire(1))
|
|
sem.Acquire(ctx, 1)
|
|
tries = append(tries, tryAcquire(1))
|
|
|
|
want := []bool{true, false, true, false}
|
|
for i := range tries {
|
|
if tries[i] != want[i] {
|
|
t.Errorf("tries[%d]: got %t, want %t", i, tries[i], want[i])
|
|
}
|
|
}
|
|
}
|
|
|
|
func TestWeightedDoesntBlockIfTooBig(t *testing.T) {
|
|
t.Parallel()
|
|
|
|
const n = 2
|
|
sem := semaphore.NewWeighted(n)
|
|
{
|
|
ctx, cancel := context.WithCancel(context.Background())
|
|
defer cancel()
|
|
go sem.Acquire(ctx, n+1)
|
|
}
|
|
|
|
g, ctx := errgroup.WithContext(context.Background())
|
|
for i := n * 3; i > 0; i-- {
|
|
g.Go(func() error {
|
|
err := sem.Acquire(ctx, 1)
|
|
if err == nil {
|
|
time.Sleep(1 * time.Millisecond)
|
|
sem.Release(1)
|
|
}
|
|
return err
|
|
})
|
|
}
|
|
if err := g.Wait(); err != nil {
|
|
t.Errorf("semaphore.NewWeighted(%v) failed to AcquireCtx(_, 1) with AcquireCtx(_, %v) pending", n, n+1)
|
|
}
|
|
}
|
|
|
|
// TestLargeAcquireDoesntStarve times out if a large call to Acquire starves.
|
|
// Merely returning from the test function indicates success.
|
|
func TestLargeAcquireDoesntStarve(t *testing.T) {
|
|
t.Parallel()
|
|
|
|
ctx := context.Background()
|
|
n := int64(runtime.GOMAXPROCS(0))
|
|
sem := semaphore.NewWeighted(n)
|
|
running := true
|
|
|
|
var wg sync.WaitGroup
|
|
wg.Add(int(n))
|
|
for i := n; i > 0; i-- {
|
|
sem.Acquire(ctx, 1)
|
|
go func() {
|
|
defer func() {
|
|
sem.Release(1)
|
|
wg.Done()
|
|
}()
|
|
for running {
|
|
time.Sleep(1 * time.Millisecond)
|
|
sem.Release(1)
|
|
sem.Acquire(ctx, 1)
|
|
}
|
|
}()
|
|
}
|
|
|
|
sem.Acquire(ctx, n)
|
|
running = false
|
|
sem.Release(n)
|
|
wg.Wait()
|
|
}
|