| /* |
| * |
| * Copyright 2017 gRPC 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. |
| * |
| */ |
| |
| // Benchmark options for safe config selector type. |
| |
| package primitives_test |
| |
| import ( |
| "sync" |
| "sync/atomic" |
| "testing" |
| "time" |
| "unsafe" |
| ) |
| |
| type safeUpdaterAtomicAndCounter struct { |
| ptr unsafe.Pointer // *countingFunc |
| } |
| |
| type countingFunc struct { |
| mu sync.RWMutex |
| f func() |
| } |
| |
| func (s *safeUpdaterAtomicAndCounter) call() { |
| cfPtr := atomic.LoadPointer(&s.ptr) |
| var cf *countingFunc |
| for { |
| cf = (*countingFunc)(cfPtr) |
| cf.mu.RLock() |
| cfPtr2 := atomic.LoadPointer(&s.ptr) |
| if cfPtr == cfPtr2 { |
| // Use cf with confidence! |
| break |
| } |
| // cf changed; try to use the new one instead, because the old one is |
| // no longer valid to use. |
| cf.mu.RUnlock() |
| cfPtr = cfPtr2 |
| } |
| defer cf.mu.RUnlock() |
| cf.f() |
| } |
| |
| func (s *safeUpdaterAtomicAndCounter) update(f func()) { |
| newCF := &countingFunc{f: f} |
| oldCFPtr := atomic.SwapPointer(&s.ptr, unsafe.Pointer(newCF)) |
| if oldCFPtr == nil { |
| return |
| } |
| (*countingFunc)(oldCFPtr).mu.Lock() |
| (*countingFunc)(oldCFPtr).mu.Unlock() //lint:ignore SA2001 necessary to unlock after locking to unblock any RLocks |
| } |
| |
| type safeUpdaterRWMutex struct { |
| mu sync.RWMutex |
| f func() |
| } |
| |
| func (s *safeUpdaterRWMutex) call() { |
| s.mu.RLock() |
| defer s.mu.RUnlock() |
| s.f() |
| } |
| |
| func (s *safeUpdaterRWMutex) update(f func()) { |
| s.mu.Lock() |
| defer s.mu.Unlock() |
| s.f = f |
| } |
| |
| type updater interface { |
| call() |
| update(f func()) |
| } |
| |
| func benchmarkSafeUpdater(b *testing.B, u updater) { |
| t := time.NewTicker(time.Second) |
| go func() { |
| for range t.C { |
| u.update(func() {}) |
| } |
| }() |
| b.RunParallel(func(pb *testing.PB) { |
| u.update(func() {}) |
| for pb.Next() { |
| u.call() |
| } |
| }) |
| t.Stop() |
| } |
| |
| func BenchmarkSafeUpdaterAtomicAndCounter(b *testing.B) { |
| benchmarkSafeUpdater(b, &safeUpdaterAtomicAndCounter{}) |
| } |
| |
| func BenchmarkSafeUpdaterRWMutex(b *testing.B) { |
| benchmarkSafeUpdater(b, &safeUpdaterRWMutex{}) |
| } |