130 lines
3.0 KiB
Go
130 lines
3.0 KiB
Go
// Copyright 2018 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package sync
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import (
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"context"
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"runtime"
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"sync/atomic"
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"testing"
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"time"
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)
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func TestGateBasic(t *testing.T) {
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var g Gate
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if !g.Enter() {
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t.Fatalf("Enter failed before Close")
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}
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g.Leave()
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g.Close()
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if g.Enter() {
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t.Fatalf("Enter succeeded after Close")
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}
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}
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func TestGateConcurrent(t *testing.T) {
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// Each call to testGateConcurrentOnce tests behavior around a single call
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// to Gate.Close, so run many short tests to increase the probability of
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// flushing out any issues.
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totalTime := 5 * time.Second
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timePerTest := 20 * time.Millisecond
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numTests := int(totalTime / timePerTest)
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for i := 0; i < numTests; i++ {
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testGateConcurrentOnce(t, timePerTest)
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}
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}
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func testGateConcurrentOnce(t *testing.T, d time.Duration) {
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const numGoroutines = 1000
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ctx, cancel := context.WithCancel(context.Background())
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var wg WaitGroup
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defer func() {
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cancel()
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wg.Wait()
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}()
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var g Gate
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closeState := int32(0) // set to 1 before g.Close() and 2 after it returns
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// Start a large number of goroutines that repeatedly attempt to enter the
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// gate and get the expected result.
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for i := 0; i < numGoroutines; i++ {
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wg.Add(1)
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go func() {
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defer wg.Done()
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for ctx.Err() == nil {
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closedBeforeEnter := atomic.LoadInt32(&closeState) == 2
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if g.Enter() {
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closedBeforeLeave := atomic.LoadInt32(&closeState) == 2
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g.Leave()
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if closedBeforeEnter {
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t.Errorf("Enter succeeded after Close")
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return
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}
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if closedBeforeLeave {
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t.Errorf("Close returned before Leave")
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return
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}
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} else {
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if atomic.LoadInt32(&closeState) == 0 {
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t.Errorf("Enter failed before Close")
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return
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}
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}
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// Go does not preempt busy loops until Go 1.14.
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runtime.Gosched()
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}
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}()
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}
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// Allow goroutines to enter the gate successfully for half of the test's
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// duration, then close the gate and allow goroutines to fail to enter the
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// gate for the remaining half.
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time.Sleep(d / 2)
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atomic.StoreInt32(&closeState, 1)
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g.Close()
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atomic.StoreInt32(&closeState, 2)
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time.Sleep(d / 2)
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}
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func BenchmarkGateEnterLeave(b *testing.B) {
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var g Gate
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for i := 0; i < b.N; i++ {
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g.Enter()
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g.Leave()
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}
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}
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func BenchmarkGateClose(b *testing.B) {
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for i := 0; i < b.N; i++ {
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var g Gate
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g.Close()
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}
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}
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func BenchmarkGateEnterLeaveAsyncClose(b *testing.B) {
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for i := 0; i < b.N; i++ {
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var g Gate
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g.Enter()
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go func() {
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g.Leave()
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}()
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g.Close()
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}
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}
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