{"id":10006268,"date":"2022-08-21T18:20:04","date_gmt":"2022-08-21T10:20:04","guid":{"rendered":"https:\/\/ityet.com\/?p=10006268"},"modified":"2022-08-21T18:20:04","modified_gmt":"2022-08-21T10:20:04","slug":"%e9%9d%a2%e8%af%95%e5%ae%98%ef%bc%9a%e5%93%a5%e4%bb%acgo%e8%af%ad%e8%a8%80%e7%9a%84%e8%af%bb%e5%86%99%e9%94%81%e4%ba%86%e8%a7%a3%e5%a4%9a%e5%b0%91%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/itmax.cn\/?p=10006268","title":{"rendered":"\u9762\u8bd5\u5b98\uff1a\u54e5\u4eecGo\u8bed\u8a00\u7684\u8bfb\u5199\u9501\u4e86\u89e3\u591a\u5c11\uff1f"},"content":{"rendered":"

\u524d\u8a00<\/h2>\n
\n

\u54c8\u55bd\uff0c\u5927\u5bb6\u597d\uff0c\u6211\u662fasong<\/code>\u3002<\/p>\n

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Golang\u7248\u672c\uff1a1.118<\/strong><\/p>\n

\u8bfb\u5199\u9501\u7b80\u4ecb<\/h2>\n

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\u4e3a\u4ec0\u4e48\u8981\u6709\u8bfb\u9501<\/h3>\n

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\u4e3e\u4e2a\u4f8b\u5b50\u8bf4\u660e\uff0c\u5728Golang<\/code>\u4e2d\u53d8\u91cf\u7684\u8d4b\u503c\u4e0d\u662f\u5e76\u53d1\u5b89\u5168\u7684\uff0c\u6bd4\u5982\u5bf9\u4e00\u4e2aint<\/code>\u578b\u53d8\u91cf\u6267\u884ccount++<\/code>\u64cd\u4f5c\uff0c\u5728\u5e76\u53d1\u4e0b\u6267\u884c\u5c31\u4f1a\u51fa\u73b0\u9884\u671f\u4e4b\u5916\u7684\u7ed3\u679c\uff0c\u56e0\u4e3acount++<\/code>\u64cd\u4f5c\u5206\u4e3a\u4e09\u90e8\u5206\uff1a\u8bfb\u53d6count<\/code>\u7684\u503c\u3001\u5c06count<\/code>\u7684\u503c\u52a01<\/code>\uff0c\u7136\u540e\u518d\u5c06\u7ed3\u679c\u8d4b\u503c\u7ed9count<\/code>\uff0c\u8fd9\u4e0d\u662f\u4e00\u4e2a\u539f\u5b50\u6027\u64cd\u4f5c\uff0c\u672a\u52a0\u9501\u65f6\u5728\u591a\u4e2a\u7ebf\u7a0b\u540c\u65f6\u5bf9\u8be5\u53d8\u91cf\u6267\u884ccount++<\/code>\u64cd\u4f5c\u4f1a\u9020\u6210\u6570\u636e\u4e0d\u4e00\u81f4\uff0c\u901a\u8fc7\u52a0\u4e0a\u5199\u9501\u53ef\u4ee5\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\uff0c\u4f46\u662f\u5728\u8bfb\u53d6\u7684\u65f6\u5019\u6211\u4eec\u4e0d\u52a0\u8bfb\u9501\u4f1a\u600e\u4e48\u6837\u5462\uff1f\u5199\u4e2a\u4f8b\u5b50\u6765\u770b\u4e00\u4e0b\uff0c\u53ea\u52a0\u5199\u9501\uff0c\u4e0d\u52a0\u8bfb\u9501\uff1a<\/p>\n

package main\n\nimport "sync"\n\nconst maxValue = 3\n\ntype test struct {\n    rw sync.RWMutex\n    index int\n}\n\nfunc (t *test) Get() int {\n    return t.index\n}\n\nfunc (t *test)Set() {\n    t.rw.Lock()\n    t.index++\n    if t.index >= maxValue{\n        t.index =0\n    }\n    t.rw.Unlock()\n}\n\nfunc main()  {\n    t := test{}\n    sw := sync.WaitGroup{}\n    for i:=0; i < 100000; i++{\n        sw.Add(2)\n        go func() {\n            t.Set()\n            sw.Done()\n        }()\n        go func() {\n            val := t.Get()\n            if val >= maxValue{\n                print("get value error| value=", val, "\/n")\n            }\n            sw.Done()\n        }()\n    }\n    sw.Wait()\n}<\/code><\/pre>\n
\u8fd0\u884c\u7ed3\u679c\uff1a<\/p>\n
get value error| value=3\nget value error| value=3\nget value error| value=3\nget value error| value=3\nget value error| value=3\n.....<\/code><\/pre>\n
\u6bcf\u6b21\u8fd0\u884c\u7ed3\u679c\u90fd\u662f\u4e0d\u56fa\u5b9a\u7684\uff0c\u56e0\u4e3a\u6211\u4eec\u6ca1\u6709\u52a0\u8bfb\u9501\uff0c\u5982\u679c\u5141\u8bb8\u540c\u65f6\u8bfb\u548c\u5199\uff0c\u8bfb\u53d6\u5230\u7684\u6570\u636e\u6709\u53ef\u80fd\u5c31\u662f\u4e2d\u95f4\u72b6\u6001\uff0c\u6240\u4ee5\u6211\u4eec\u53ef\u4ee5\u603b\u7ed3\u51fa\u6765\u8bfb\u9501\u662f\u5f88\u6709\u5fc5\u8981\u7684\uff0c\u8bfb\u9501\u53ef\u4ee5\u9632\u6b62\u8bfb\u5230\u5199\u4e2d\u95f4\u7684\u503c\u3002<\/p>\n
\u8bfb\u5199\u9501\u7684\u63d2\u961f\u7b56\u7565<\/h3>\n
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\u5047\u8bbe\u73b0\u5728\u67095\u4e2agoroutine<\/code>\u5206\u522b\u662fG1<\/code>\u3001G2<\/code>\u3001G3<\/code>\u3001G4<\/code>\u3001G5<\/code>\uff0c\u73b0\u5728G1<\/code>\u3001G2<\/code>\u83b7\u53d6\u8bfb\u9501\u6210\u529f\uff0c\u8fd8\u6ca1\u91ca\u653e\u8bfb\u9501\uff0cG3<\/code>\u8981\u6267\u884c\u5199\u64cd\u4f5c\uff0c\u83b7\u53d6\u5199\u9501\u5931\u8d25\u5c31\u4f1a\u963b\u585e\u7b49\u5f85\uff0c\u5f53\u524d\u963b\u585e\u5199\u9501\u7684\u8bfb\u9501goroutine<\/code>\u6570\u91cf\u4e3a2\uff1a<\/p>\n
\"\"<\/p>\n
\u540e\u7eedG4<\/code>\u8fdb\u6765\u60f3\u8981\u83b7\u53d6\u8bfb\u9501\uff0c\u8fd9\u65f6\u5979\u5c31\u4f1a\u5224\u65ad\u5982\u679c\u5f53\u524d\u6709\u5199\u9501\u7684goroutine<\/code>\u6b63\u5728\u963b\u585e\u7b49\u5f85\uff0c\u4e3a\u4e86\u907f\u514d\u5199\u9501\u9965\u997f\uff0c\u90a3\u8fd9\u4e2aG4<\/code>\u4e5f\u4f1a\u8fdb\u5165\u963b\u585e\u7b49\u5f85\uff0c\u540e\u7eedG5<\/code>\u8fdb\u6765\u60f3\u8981\u83b7\u53d6\u5199\u9501\uff0c\u56e0\u4e3aG3<\/code>\u5728\u5360\u7528\u4e92\u65a5\u9501\uff0c\u6240\u4ee5G5<\/code>\u4f1a\u8fdb\u5165\u81ea\u65cb\/\u4f11\u7720 \u963b\u585e\u7b49\u5f85\uff1b<\/p>\n
\"\"<\/p>\n
\u73b0\u5728G1<\/code>\u3001G2<\/code>\u91ca\u653e\u4e86\u8bfb\u9501\uff0c\u5f53\u91ca\u653e\u8bfb\u9501\u662f\u5224\u65ad\u5982\u679c\u963b\u585e\u5199\u9501goroutine\u7684\u8bfb\u9501goroutine\u6570\u91cf\u4e3a0\u4e86\u5e76\u4e14\u6709\u5199\u9501\u7b49\u5f85\u5c31\u4f1a\u5524\u9192\u6b63\u5728\u963b\u585e\u7b49\u5f85\u7684\u5199\u9501G3<\/code>\uff0cG3<\/code>\u5f97\u5230\u4e86\u5524\u9192\uff1a<\/p>\n
\"\"<\/p>\n
G3<\/code>\u5904\u7406\u5b8c\u5199\u64cd\u4f5c\u540e\u4f1a\u91ca\u653e\u5199\u9501\uff0c\u8fd9\u4e00\u6b65\u4f1a\u540c\u65f6\u5524\u9192\u7b49\u5f85\u7684\u8bfb\u9501\/\u5199\u9501\u7684goroutine<\/code>\uff0c\u81f3\u4e8eG4<\/code>\u3001G5<\/code>\u8c01\u80fd\u5148\u83b7\u53d6\u9501\u5c31\u770b\u8c01\u6bd4\u8f83\u5feb\u4e86\uff0c\u5c31\u50cf\u62a2\u5ab3\u5987\u4e00\u6837\uff0c\u5148\u4e0b\u624b\u7684\u5148\u5f97\u5440\u3002<\/p>\n
\u8bfb\u5199\u9501\u7684\u5b9e\u73b0<\/h2>\n
\u63a5\u4e0b\u6765\u6211\u4eec\u5c31\u6df1\u5165\u6e90\u7801\u5206\u6790\u4e00\u4e0b\uff0c\u5148\u770b\u4e00\u4e0bRWMutex<\/code>\u7ed3\u6784\u90fd\u6709\u5565\uff1a<\/p>\n
type RWMutex struct {\n    w           Mutex  \/\/ held if there are pending writers\n    writerSem   uint32 \/\/ semaphore for writers to wait for completing readers\n    readerSem   uint32 \/\/ semaphore for readers to wait for completing writers\n    readerCount int32  \/\/ number of pending readers\n    readerWait  int32  \/\/ number of departing readers\n}<\/code><\/pre>\n