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// Copyright 2020 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package goid
import (
"runtime"
"sync"
"testing"
"time"
)
func TestUniquenessAndConsistency(t *testing.T) {
const (
numGoroutines = 5000
// maxID is not an intrinsic property of goroutine IDs; it is only a
// property of how the Go runtime currently assigns them. Future
// changes to the Go runtime may require that maxID be raised, or that
// assertions regarding it be removed entirely.
maxID = numGoroutines + 1000
)
var (
goidsMu sync.Mutex
goids = make(map[int64]struct{})
checkedWG sync.WaitGroup
exitCh = make(chan struct{})
)
for i := 0; i < numGoroutines; i++ {
checkedWG.Add(1)
go func() {
id := Get()
if id > maxID {
t.Errorf("observed unexpectedly large goroutine ID %d", id)
}
goidsMu.Lock()
if _, dup := goids[id]; dup {
t.Errorf("observed duplicate goroutine ID %d", id)
}
goids[id] = struct{}{}
goidsMu.Unlock()
checkedWG.Done()
for {
if curID := Get(); curID != id {
t.Errorf("goroutine ID changed from %d to %d", id, curID)
// Don't spam logs by repeating the check; wait quietly for
// the test to finish.
<-exitCh
return
}
// Check if the test is over.
select {
case <-exitCh:
return
default:
}
// Yield to other goroutines, and possibly migrate to another P.
runtime.Gosched()
}
}()
}
// Wait for all goroutines to perform uniqueness checks.
checkedWG.Wait()
// Wait for an additional second to allow goroutines to spin checking for
// ID consistency.
time.Sleep(time.Second)
// Request that all goroutines exit.
close(exitCh)
}
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