Fix lecture
This commit is contained in:
Fedor Korotkiy
parent
29089ced33
commit
22fc994458
5 changed files with 38 additions and 136 deletions
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@ -3,6 +3,11 @@ Concurrency with Shared Memory
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Фёдор Короткий
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* Concurrency with Shared Memory
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- Принципы синхронизации, такие же как в C++ или java.
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- Различается набор инструментов в стандартной библиотеке.
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* Happens Before
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- Одно событие в программе может _произойти_раньше_ (_happens_before_) другого события.
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@ -296,3 +301,36 @@ Concurrency with Shared Memory
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.play synconce/map.go /type result/,/OMIT/
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* sync.Cond
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type Once struct {
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done, running bool
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mu sync.Mutex
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cond *sync.Cond
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}
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func (once *Once) Do(f func()) {
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once.mu.Lock()
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defer once.mu.Unlock()
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if done {
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return
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}
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if running {
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once.cond.Wait() // releases and acquires mutex
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return
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}
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running = true
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once.mu.Unlock()
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f()
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once.mu.Lock()
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done = true
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once.cond.Broadcast()
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}
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* golang.org/x/sync
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Пакеты в golang.org/x содержат код, который не вошёл в стандартную библиотеку.
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- errgroup - `sync.WaitGroup` в встроенной обработкой ошибок
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- semaphore - семафор
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- singleflight - дедубликация вызовов
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@ -1,67 +0,0 @@
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// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
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// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
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package memo_test
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import (
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"testing"
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"gopl.io/ch9/memo1"
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"gopl.io/ch9/memotest"
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)
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var httpGetBody = memotest.HTTPGetBody
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func Test(t *testing.T) {
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m := memo.New(httpGetBody)
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memotest.Sequential(t, m)
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}
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// NOTE: not concurrency-safe! Test fails.
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func TestConcurrent(t *testing.T) {
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m := memo.New(httpGetBody)
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memotest.Concurrent(t, m)
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}
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/*
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//!+output
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$ go test -v gopl.io/ch9/memo1
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=== RUN Test
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https://golang.org, 175.026418ms, 7537 bytes
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https://godoc.org, 172.686825ms, 6878 bytes
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https://play.golang.org, 115.762377ms, 5767 bytes
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http://gopl.io, 749.887242ms, 2856 bytes
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https://golang.org, 721ns, 7537 bytes
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https://godoc.org, 152ns, 6878 bytes
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https://play.golang.org, 205ns, 5767 bytes
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http://gopl.io, 326ns, 2856 bytes
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--- PASS: Test (1.21s)
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PASS
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ok gopl.io/ch9/memo1 1.257s
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//!-output
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*/
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/*
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//!+race
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$ go test -run=TestConcurrent -race -v gopl.io/ch9/memo1
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=== RUN TestConcurrent
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...
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WARNING: DATA RACE
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Write by goroutine 36:
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runtime.mapassign1()
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~/go/src/runtime/hashmap.go:411 +0x0
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gopl.io/ch9/memo1.(*Memo).Get()
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~/gobook2/src/gopl.io/ch9/memo1/memo.go:32 +0x205
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...
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Previous write by goroutine 35:
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runtime.mapassign1()
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~/go/src/runtime/hashmap.go:411 +0x0
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gopl.io/ch9/memo1.(*Memo).Get()
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~/gobook2/src/gopl.io/ch9/memo1/memo.go:32 +0x205
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...
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Found 1 data race(s)
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FAIL gopl.io/ch9/memo1 2.393s
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//!-race
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*/
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@ -1,23 +0,0 @@
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// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
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// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
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package memo_test
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import (
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"testing"
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"gopl.io/ch9/memo2"
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"gopl.io/ch9/memotest"
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)
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var httpGetBody = memotest.HTTPGetBody
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func Test(t *testing.T) {
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m := memo.New(httpGetBody)
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memotest.Sequential(t, m)
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}
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func TestConcurrent(t *testing.T) {
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m := memo.New(httpGetBody)
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memotest.Concurrent(t, m)
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}
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@ -1,23 +0,0 @@
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// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
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// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
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package memo_test
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import (
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"testing"
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"gopl.io/ch9/memo3"
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"gopl.io/ch9/memotest"
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)
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var httpGetBody = memotest.HTTPGetBody
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func Test(t *testing.T) {
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m := memo.New(httpGetBody)
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memotest.Sequential(t, m)
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}
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func TestConcurrent(t *testing.T) {
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m := memo.New(httpGetBody)
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memotest.Concurrent(t, m)
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}
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@ -1,23 +0,0 @@
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// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
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// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
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package memo_test
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import (
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"testing"
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"gopl.io/ch9/memo4"
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"gopl.io/ch9/memotest"
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)
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var httpGetBody = memotest.HTTPGetBody
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func Test(t *testing.T) {
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m := memo.New(httpGetBody)
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memotest.Sequential(t, m)
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}
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func TestConcurrent(t *testing.T) {
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m := memo.New(httpGetBody)
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memotest.Concurrent(t, m)
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}
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