go\u8bed\u8a00\u5b9e\u73b0\u9501<\/a><\/p>\nwaitgroup<\/h2>\n
\u4fe1\u53f7\u91cf\uff0cWait\u4f1a\u5361\u4f4f\u3002\u7b49\u5f85\u6240\u6709goroutine\u6267\u884c\u5b8c\u6210\u518d\u6267\u884cWait\u4e4b\u540e\u7684\u5185\u5bb9<\/p>\n
\/**\n * Createby GoLand\n * User xzw jsjxzw@163.com\n * Date 2021\/6\/25\n * Time \u4e0b\u53483:37\n *\/\n\npackage main\n\nimport (\n \"sync\"\n \"sync\/atomic\"\n)\n\nvar counter int64\n\nfunc incr() {\n for i := 0; i < 10; i++ {\n \/\/ \u6b64\u5904\u4f7f\u7528 atomic \u539f\u8bed cas \uff08compare and swap\uff09\n atomic.AddInt64(&counter, 1)\n }\n}\n\nfunc main() {\n var wg sync.WaitGroup\n for i := 0; i < 10000; i++ {\n wg.Add(1)\n go func() {\n defer wg.Done()\n incr()\n }()\n }\n wg.Wait()\n println(counter)\n}\n<\/code><\/pre>\natomic \u539f\u8bed<\/h2>\n
![\"image-20210708162500635\"](\"https:\/\/oss.wyxxt.org.cn\/images\/2021\/09\/18\/image-20210708162500635.png\")
<\/p>\n
chan<\/h2>\n
channel size \u4e3a\u591a\u5c11\u5e76\u53d1\u91cf\u5c31\u662f\u591a\u5c11,\u4e3a1\u4e32\u884c<\/p>\n
\/**\n * Createby GoLand\n * User xzw jsjxzw@163.com\n * Date 2021\/6\/25\n * Time \u4e0b\u53483:48\n *\/\n\npackage main\n\nimport \"sync\"\n\ntype Lock struct {\n c chan struct{}\n}\n\nfunc NewLock() Lock {\n var l Lock\n l.c = make(chan struct{}, 1)\n l.c <- struct{}{}\n return l\n}\nfunc (l Lock) Lock() bool {\n lockResult := false\n select {\n case <-l.c:\n lockResult = true\n default:\n }\n return lockResult\n}\nfunc (l Lock) UnLock() {\n l.c <- struct{}{}\n}\n\nvar counter int\n\nvar l = NewLock()\n\nfunc incr() {\n if !l.Lock() {\n incr()\n return\n }\n for i := 0; i < 10; i++ {\n counter++\n }\n l.UnLock()\n}\n\nfunc main() {\n var wg sync.WaitGroup\n\n for i := 0; i < 1000; i++ {\n wg.Add(1)\n go func() {\n defer wg.Done()\n incr()\n }()\n }\n wg.Wait()\n println(counter)\n}\n<\/code><\/pre>\nmutex<\/h2>\n
https:\/\/juejin.cn\/post\/6986473832202633229#heading-7<\/p>\n
sync.Mutex \u4e92\u65a5\u9501<\/p>\n
type Mutex struct {\n state int32\n sema uint32 \/\/ \u4fe1\u53f7\u91cf\u53d8\u91cf\uff0c\u7528\u6765\u63a7\u5236\u7b49\u5f85 goroutine \u7684\u963b\u585e\u4f11\u7720\u548c\u5524\u9192\n}\n\/\/ state \u6700\u4f4e\u4e09\u4f4d \n\/\/ 001 mutexLocked\n\/\/ 010 mutexWoken\n\/\/ 100 mutexStarving\n\/\/ state\u603b\u5171\u662f32\u4f4d\u957f\u5ea6\uff0c\u6240\u4ee5\u5269\u4e0b\u7684\u4f4d\u7f6e\uff0c\u7528\u6765\u8868\u793a\u53ef\u4ee5\u67091<<(32-3)\u4e2aGoroutine \u7b49\u5f85\u4e92\u65a5\u9501\u7684\u91ca\u653e\uff1a\n\nconst (\n mutexLocked = 1 << iota \/\/ mutex is locked \u6b21\u6570iota\u4e3a0\n mutexWoken \/\/ 010 2 \u662f\u5426\u5524\u9192 1 << iota\n mutexStarving \/\/ 100 4 \u662f\u5426\u9965\u997f 1 << iota\n mutexWaiterShift = iota \/\/ \u6b64\u5904iota\u4e3a3\uff0ciota\u5728\u4e00\u4e2aconst\u5185\u7d2f\u8ba1\n starvationThresholdNs = 1e6\n)\n<\/code><\/pre>\nLock<\/h3>\nfunc (m *Mutex) Lock() {\n \/\/ Fast path: grab unlocked mutex.\n if atomic.CompareAndSwapInt32(&m.state, 0, mutexLocked) {\n if race.Enabled {\n race.Acquire(unsafe.Pointer(m))\n }\n return\n }\n \/\/ Slow path (outlined so that the fast path can be inlined)\n m.lockSlow()\n}\n<\/code><\/pre>\nlockSlow<\/h3>\nfunc (m *Mutex) lockSlow() {\n \/\/ \u7b49\u5f85\u65f6\u95f4\n var waitStartTime int64\n \/\/ \u9965\u997f\u6807\u8bb0\n starving := false\n \/\/ \u5524\u9192\u6807\u8bb0\n awoke := false\n \/\/ \u81ea\u65cb\u6b21\u6570\n iter := 0\n \/\/ \u5f53\u524d\u9501\u72b6\u6001\n old := m.state\n for {\n \/\/ \u9501\u662f\u975e\u9965\u997f\u72b6\u6001\uff0c\u9501\u8fd8\u6ca1\u6709\u91ca\u653e\uff0c\u5c1d\u8bd5\u81ea\u65cb\n if old&(mutexLocked|mutexStarving) == mutexLocked && runtime_canSpin(iter) {\n \/\/ awoke\u672a\u5524\u9192 \u6ca1\u6709\u5176\u4ed6\u6b63\u5728\u5524\u9192\u7684\u8282\u70b9 \u5f53\u524d\u6709\u6b63\u5728\u7b49\u5f85\u7684goroutine \n if !awoke && old&mutexWoken == 0 && old>>mutexWaiterShift != 0 &&\n \/\/ CAS \u8bbe\u7f6e state \u7684 mutexWoken\u72b6\u6001\u4f4d\u4e3a1\n atomic.CompareAndSwapInt32(&m.state, old, old|mutexWoken) {\n \/\/ CAS\u6210\u529f\uff0c\u5524\u9192awoke\u4e3atrue\n awoke = true\n }\n \/\/ \u81ea\u65cb\n runtime_doSpin()\n \/\/ \u81ea\u65cb\u6b21\u6570\u52a01\n iter++\n \/\/ \u8bbe\u7f6e\u5f53\u524d\u9501\u7684\u72b6\u6001\n old = m.state\n continue\n }\n new := old\n \/\/ \u975e\u9965\u997f\u72b6\u6001\n if old&mutexStarving == 0 {\n \/\/ \u9501\u72b6\u6001\u4f4d\u8bbe\u4e3a1\n new |= mutexLocked\n }\n \/\/ \u5982\u679c\u9501\u65e7\u72b6\u6001\u662f\u88ab\u9501\u5b9a\u6216\u8005\u5904\u4e8e\u9965\u997f\u72b6\u6001\uff0c\u5219waiter\u52a0\u4e00\uff0c\u8868\u793a\u4e00\u4e2a\u7b49\u5f85\u8ba1\u6570\n if old&(mutexLocked|mutexStarving) != 0 {\n new += 1 << mutexWaiterShift\n }\n \/\/ \u5982\u679c\u5f53\u524dgoroutine\u662f\u9965\u997f\u6807\u8bb0\u5e76\u4e14\u5df2\u7ecf\u4e0a\u9501\uff0c\u90a3\u4e48\u9501 mutexStarving \u72b6\u6001\u4e3a\u8bbe\u7f6e\u4e3a1\n if starving && old&mutexLocked != 0 {\n new |= mutexStarving\n }\n \/\/ \u5982\u679c\u5f53\u524dgoroutine\u662f\u5524\u9192\u6807\u8bb0\n if awoke {\n \/\/ \u9501\u72b6\u6001\u4e3a\u672a\u5524\u9192\uff0c\u5f02\u5e38\u60c5\u51b5\n if new&mutexWoken == 0 {\n throw(\"sync: inconsistent mutex state\")\n }\n \/\/ \u6e05\u9664\u5524\u9192\u6807\u8bb0\u4f4d\n new &^= mutexWoken\n }\n \/\/ CAS \u8bbe\u7f6e\u65b0\u72b6\u6001\n if atomic.CompareAndSwapInt32(&m.state, old, new) {\n \/\/ \u5982\u679c\u539f\u6765\u72b6\u6001\u6ca1\u6709\u4e0a\u9501\u4e5f\u6ca1\u6709\u9965\u997f\n if old&(mutexLocked|mutexStarving) == 0 {\n break \/\/ locked the mutex with CAS\n }\n \/\/ \u5230\u8fd9\u91cc\u65f6\uff0c\u4ee3\u8868\u6ca1\u6709\u83b7\u5f97\u9501\n queueLifo := waitStartTime != 0\n \/\/ \u5982\u679c\u7b49\u5f85\u65f6\u95f4\u4e3a0\uff0c\u521d\u59cb\u5316\u7b49\u5f85\u65f6\u95f4\n if waitStartTime == 0 {\n waitStartTime = runtime_nanotime()\n }\n \/\/ \u963b\u585e\u7b49\u5f85,\u5f53\u524d goroutine \u8fdb\u884c\u4f11\u7720\n runtime_SemacquireMutex(&m.sema, queueLifo, 1)\n \/\/ \u5524\u9192\u4e4b\u540e\u68c0\u67e5\u9501\u662f\u5426\u5e94\u8be5\u5904\u4e8e\u9965\u997f\u72b6\u6001\uff08\u7b49\u5f85\u65f6\u95f4\u8d85\u8fc71ms\uff09\uff0c\u5e76\u8bbe\u7f6e starving \u53d8\u91cf\n starving = starving || runtime_nanotime()-waitStartTime > starvationThresholdNs\n old = m.state\n \/\/ \u5982\u679c\u5df2\u7ecf\u5904\u4e8e\u9965\u997f\u72b6\u6001\n if old&mutexStarving != 0 {\n \/\/ \u5df2\u9501\u6216\u5df2\u5524\u9192 \u6216\u8005 0 \u4e2a goroutine \u7b49\u5f85\u4e92\u65a5\u9501\u7684\u91ca\u653e\uff0c\u5f02\u5e38\n if old&(mutexLocked|mutexWoken) != 0 || old>>mutexWaiterShift == 0 {\n throw(\"sync: inconsistent mutex state\")\n }\n \/\/ \u4e0e\u4e0b\u9762\u7684atomic.AddInt32($m.state, delta)\u7ed3\u5408\u7406\u89e3\n \/\/ \u7b49\u5f85\u4e92\u65a5\u9501\u91ca\u653e\u7684 goroutine - 1\n \/\/ \u4e0a\u9501\n delta := int32(mutexLocked - 1<<mutexWaiterShift)\n \/\/ \u5982\u679c\u5f53\u524d goroutine \u4e0d\u662f\u9965\u997f\u72b6\u6001\uff0c\u6216\u8005\u6709\u4e14\u53ea\u6709 1 \u4e2a goroutine \u7b49\u5f85\u4e92\u65a5\u9501\u7684\u91ca\u653e\n if !starving || old>>mutexWaiterShift == 1 {\n \/\/ \u9965\u997f\u6a21\u5f0f\u4f4d-1\uff08\u79fb\u9664\u9965\u997f\u6a21\u5f0f\uff09\n delta -= mutexStarving\n }\n \/\/ atomic add \u64cd\u4f5c\uff0c\u8bbe\u7f6e\u72b6\u6001,\u62a2\u9501\n atomic.AddInt32(&m.state, delta)\n break\n }\n awoke = true\n iter = 0\n } else {\n old = m.state\n }\n }\n\n if race.Enabled {\n race.Acquire(unsafe.Pointer(m))\n }\n}\n<\/code><\/pre>\n![\"img\"](\"https:\/\/oss.wyxxt.org.cn\/images\/2021\/09\/18\/e9f912e7bc7c646cc9110cf492bca019.png\")
<\/p>\n
Unlock<\/p>\n
![\"20201218225221\"](\"https:\/\/oss.wyxxt.org.cn\/images\/2021\/09\/18\/20201218225221.png\")
<\/p>\n
\/**\n * Createby GoLand\n * User xzw jsjxzw@163.com\n * Date 2021\/6\/25\n * Time \u4e0b\u53483:42\n *\/\n\npackage main\n\nimport \"sync\"\n\nvar counter int\nvar l sync.Mutex\n\nfunc incr() {\n l.Lock()\n for i := 0; i < 10; i++ {\n counter++\n }\n l.Unlock()\n}\nfunc main() {\n var wg sync.WaitGroup\n for i := 0; i < 1000; i++ {\n wg.Add(1)\n go func() {\n defer wg.Done()\n incr()\n }()\n }\n wg.Wait()\n println(counter)\n}\n\n<\/code><\/pre>\nRWMutex<\/h2>\n
https:\/\/segmentfault.com\/a\/1190000039712353<\/p>\n
once<\/h2>\n\/**\n * Createby GoLand\n * User xzw jsjxzw@163.com\n * Date 2021\/6\/25\n * Time \u4e0b\u53483:59\n *\/\n\npackage main\n\nimport (\n \"fmt\"\n \"sync\"\n)\n\nvar counter int\n\nfunc incr() {\n for i := 0; i < 10; i++ {\n counter++\n }\n}\n\nfunc main() {\n var wg sync.WaitGroup\n var once sync.Once\n for i := 0; i < 1000; i++ {\n wg.Add(1)\n go func() {\n defer wg.Done()\n once.Do(incr)\n }()\n }\n wg.Wait()\n fmt.Println(counter)\n}\n\n<\/code><\/pre>\nsync.map<\/h2>\n
\u7ebf\u7a0b\u5b89\u5168\u7684map\uff0c\u6027\u80fd\u8f83\u4f4e<\/p>\n
![\"image-20210709102704809\"](\"https:\/\/oss.wyxxt.org.cn\/images\/2021\/09\/18\/image-20210709102704809.png\")
<\/p>\n
\/**\n * Createby GoLand\n * User xzw jsjxzw@163.com\n * Date 2021\/6\/25\n * Time \u4e0b\u53484:03\n *\/\n\npackage main\n\nimport (\n \"fmt\"\n \"sync\"\n \"sync\/atomic\"\n)\n\nvar counter int64\n\nfunc main() {\n var sm sync.Map\n var wg sync.WaitGroup\n for i := 0; i < 1000; i++ {\n wg.Add(1)\n go func() {\n defer wg.Done()\n n := atomic.AddInt64(&counter, 1)\n sm.Store(n, n*n)\n }()\n }\n wg.Wait()\n if v, ok := sm.Load(int64(1)); ok {\n fmt.Println(v)\n }\n\n sm.Range(func(k, v interface{}) bool {\n fmt.Print(k)\n fmt.Print(\":\")\n fmt.Print(v)\n fmt.Println()\n return true\n })\n\n}\n\n<\/code><\/pre>\n![\"image-20210701111029768\"](\"https:\/\/oss.wyxxt.org.cn\/images\/2021\/09\/18\/image-20210701111029768.png\")
<\/p>\n","protected":false},"excerpt":{"rendered":"
goroutine\u8c03\u5ea6 gorountine\u662f\u4e00\u4e2a\u7528\u6237\u6001\u7ea7\u522b\u7684\u7c7b\u7ebf\u7a0b\uff0c\u6240\u4ee5\u5b83\u7684\u5806\u6808\u4e5f\u5fc5\u7136\u662f\u5728\u7528\u6237\u6001\u7684\u8c03\u5ea6\u5668\u4e2d\u8fdb […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[15],"tags":[398],"class_list":["post-3542","post","type-post","status-publish","format-standard","hentry","category-15","tag-go"],"_links":{"self":[{"href":"https:\/\/wyxxt.org.cn\/index.php?rest_route=\/wp\/v2\/posts\/3542","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wyxxt.org.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wyxxt.org.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wyxxt.org.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/wyxxt.org.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3542"}],"version-history":[{"count":6,"href":"https:\/\/wyxxt.org.cn\/index.php?rest_route=\/wp\/v2\/posts\/3542\/revisions"}],"predecessor-version":[{"id":3791,"href":"https:\/\/wyxxt.org.cn\/index.php?rest_route=\/wp\/v2\/posts\/3542\/revisions\/3791"}],"wp:attachment":[{"href":"https:\/\/wyxxt.org.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3542"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wyxxt.org.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3542"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wyxxt.org.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3542"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}