| // 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) |
| } |