\u539f\u5b50\u64cd\u4f5c\uff1a\u4e00\u4e2a\u6216\u591a\u4e2a\u64cd\u4f5c\u5728 CPU \u6267\u884c\u8fc7\u7a0b\u4e2d\u4e0d\u88ab\u4e2d\u65ad\u7684\u7279\u6027
\n\u5f53\u6211\u4eec\u8bf4\u539f\u5b50\u64cd\u4f5c\u65f6\uff0c\u9700\u8981\u5206\u6e05\u695a\u9488\u5bf9\u7684\u662f GPU\u6307\u4ee4\u7ea7\u522b\u8fd8\u662f\u9ad8\u7ea7\u8bed\u8a00\u7ea7\u522b
\n\u4ec0\u4e48\u662f\u539f\u5b50\u64cd\u4f5c
\n\u6bd4\u5982\uff1a\u7ecf\u5178\u7684\u94f6\u884c\u8f6c\u8d26\u573a\u666f\uff0c\u662f\u8bed\u8a00\u7ea7\u522b\u7684\u539f\u5b50\u64cd\u4f5c\uff1b
\n\u800c\u5f53\u6211\u4eec\u8bf4 volatile\u4fee\u9970\u7684\u53d8\u91cf\u7684\u590d\u5408\u64cd\u4f5c\uff0c\u5176\u539f\u5b50\u6027\u4e0d\u80fd\u88ab\u4fdd\u8bc1\uff0c\u6307\u7684\u662fCPU \u6307\u4ee4\u7ea7\u522b\u3002
\n\u4e8c\u8005\u7684\u672c\u8d28\u662f\u4e00\u81f4\u7684\u3002
\n\u201c\u539f\u5b50\u64cd\u4f5c\u201d\u7684\u5b9e\u8d28\u5176\u5b9e\u5e76\u4e0d\u662f\u6307\u201c\u4e0d\u53ef\u5206\u5272\u201d\uff0c\u8fd9\u53ea\u662f\u5916\u5728\u8868\u73b0\uff0c\u672c\u8d28\u5728\u4e8e\u591a\u4e2a\u8d44\u6e90\u4e4b\u95f4\u6709\u4e00\u81f4\u6027\u7684\u8981\u6c42\uff0c\u64cd\u4f5c\u7684\u4e2d\u95f4\u6001\u5bf9\u5916\u4e0d\u53ef\u89c1\u3002
\n\u6bd4\u5982\uff1a\u5728 32 \u4f4d\u673a\u5668\u4e0a\u5199 64 \u4f4d\u7684 long \u53d8\u91cf\u6709\u4e2d\u95f4\u72b6\u6001\uff08\u53ea\u5199\u4e86 64 \u4f4d\u4e2d\u768432\u4f4d\uff09\uff1b\u94f6\u884c\u8f6c\u8d26\u64cd\u4f5c\u4e2d\u4e5f\u6709\u4e2d\u95f4\u72b6\u6001\uff08A \u5411B \u8f6c\u8d26\uff0cA \u6263\u94b1\u4e86\uff0cB \u8fd8\u6ca1\u6765\u5f97\u53ca\u52a0\u94b1)
\n\u539f\u5b50\u64cd\u4f5c\u7684\u5b9e\u73b0\u65b9\u5f0f
\nJava \u4f7f\u7528\u9501\u548c\u81ea\u65cb CAS \u5b9e\u73b0\u539f\u5b50\u64cd\u4f5c
\n\u5e76\u53d1\u5305\u4e2d\u63d0\u4f9b\u4e86\u5f88\u591a\u5e38\u7528\u7684\u539f\u5b50\u7c7b\u6765\u652f\u6301\u539f\u5b50\u64cd\u4f5c\uff1a
\n1\u3001AtomicInteger
\n2\u3001AtomicLong
\n3\u3001AtomicBoolean
\n4\u3001AtomicReference
\n5\u3001LongAdder
\nCAS \u662f\u5e76\u53d1\u5305\u7684\u57fa\u77f3\uff0c\u4f46\u7528 CAS\u6709\u4e09\u4e2a\u95ee\u9898\uff1a
\n1\u3001ABA \u95ee\u9898
\n\u6839\u6e90\uff1aCAS \u7684\u672c\u8d28\u662f\u5bf9\u53d8\u91cf\u7684 current value,\u671f\u671b\u503c expected value \u8fdb\u884c\u6bd4\u8f83\uff0c\u4e8c\u8005\u76f8\u7b49\u65f6\uff0c\u518d\u5c06\u7ed9\u5b9a\u503cgiven update value \u8bbe\u4e3a\u5f53\u524d\u503c\u3002
\n\u56e0\u6b64\u4f1a\u5b58\u5728\u4e00\u79cd\u573a\u666f\uff0c\u53d8\u91cf\u503c\u539f\u6765\u662f A\uff0c\u53d8\u6210\u4e86 B\uff0c\u53c8\u53d8\u6210\u4e86 A\uff0c\u4f7f\u7528 CAS \u68c0\u67e5\u65f6\u4f1a\u53d1\u73b0\u503c\u5e76\u672a\u53d8\u5316\uff0c\u5b9e\u9645\u4e0a\u662f\u53d8\u5316\u4e86\u3002
\n\u5bf9\u4e8e\u6570\u503c\u7c7b\u578b\u7684\u53d8\u91cf\uff0c\u6bd4\u5982 int\uff0c\u8fd9\u79cd\u95ee\u9898\u5173\u7cfb\u4e0d\u5927\uff0c\u4f46\u5bf9\u4e8e\u5f15\u7528\u7c7b\u578b\uff0c\u5219\u4f1a\u4ea7\u751f\u5f88\u5927\u5f71\u54cd\u3002
\nABA\u95ee\u9898\u89e3\u51b3\u601d\u8def\uff1a\u7248\u672c\u53f7\u3002\u5728\u53d8\u91cf\u524d\u52a0\u7248\u672c\u53f7\uff0c\u6bcf\u6b21\u53d8\u91cf\u66f4\u65b0\u65f6\u5c06\u7248\u672c\u53f7\u52a01,A -> B -> A\uff0c\u5c31\u53d8\u6210 1A ->2B ->3A\u3002
\nJDK5 \u4e4b\u540eAtomic\u5305\u4e2d\u63d0\u4f9b\u4e86AtomicStampedReference.compareAndSet() \u6765\u89e3\u51b3ABA\u95ee\u9898\u3002
\n2\u3001\u5faa\u73af\u65f6\u95f4\u957f\u5219\u5f00\u9500\u5927
\n\u81ea\u65cbCAS \u82e5\u957f\u65f6\u95f4\u4e0d\u6210\u529f\uff0c\u4f1a\u5bf9 CPU \u9020\u6210\u8f83\u5927\u5f00\u9500\u3002\u4e0d\u8fc7\u6709\u7684 JVM\u53ef\u652f\u6301 CPU\u7684 pause \u6307\u4ee4\u7684\u8bdd\uff0c\u6548\u7387\u53ef\u6709\u4e00\u5b9a\u63d0\u5347\u3002
\npause \u4f5c\u7528\uff1a
\n\u5ef6\u8fdf\u6d41\u6c34\u7ebf\u6307\u4ee4(de-pipoline)\uff0c\u4f7f CPU \u4e0d\u81f3\u4e8e\u6d88\u8017\u8fc7\u591a\u6267\u884c\u8d44\u6e90\u3002
\n\u53ef\u907f\u514d\u9000\u51fa\u5faa\u73af\u65f6\u56e0\u5185\u5b58\u987a\u5e8f\u51b2\u7a81(memorey order violation )\u5f15\u8d77CPU\u6d41\u6c34\u7ebf\u88ab\u6e05\u7a7a(CPU pipeline flush),\u4ece\u800c\u63d0\u9ad8 CPU \u7684\u6267\u884c\u6548\u7387\u3002
\n3\u3001\u53ea\u80fd\u4fdd\u8bc1\u4e00\u4e2a\u5171\u4eab\u53d8\u91cf\u7684\u539f\u5b50\u64cd\u4f5c
\nCAS \u53ea\u80fd\u5bf9\u5355\u4e2a\u5171\u4eab\u53d8\u91cf\u5982\u662f\u64cd\u4f5c\uff0c\u5bf9\u591a\u4e2a\u5171\u4eab\u53d8\u91cf\u64cd\u4f5c\u65f6\u5219\u65e0\u6cd5\u4fdd\u8bc1\u539f\u5b50\u6027\uff0c\u6b64\u65f6\u53ef\u4ee5\u7528\u9501\u3002
\n\u53e6\u5916\uff0c\u4e5f\u53ef\u201c\u53d6\u5de7\u201d\uff0c\u5c06\u591a\u4e2a\u5171\u4eab\u53d8\u91cf\u5408\u6210\u4e00\u4e2a\u5171\u4eab\u53d8\u91cf\u6765\u64cd\u4f5c\u3002\u6bd4\u5982a=2,b=t,\u5408\u5e76\u8d77\u6765 ab=2t,\u7136\u540e\u7528 CAS \u64cd\u4f5c ab.
\nJDK5 \u63d0\u4f9b AtomicReference \u4fdd\u8bc1\u5f15\u7528\u5bf9\u8c61\u95f4\u7684\u539f\u5b50\u6027\uff0c\u5b83\u53ef\u5c06\u591a\u4e2a\u53d8\u91cf\u653e\u5728\u4e00\u4e2a\u5bf9\u8c61\u4e2d\u6765\u8fdb\u884c CAS \u64cd\u4f5c\u3002
\n\u539f\u5b50\u7c7b\uff1aAtomicBoolean\uff0cAtomicInteger\uff0cAtomicLong\uff0cAtomicReference
\n\u539f\u5b50\u6570\u7ec4\uff1aAtomicIntegerArray\uff0cAtomicLongArray\uff0cAtomicReferenceArray
\n\u539f\u5b50\u5c5e\u6027\u66f4\u65b0\u5668\uff1aAtomicLongFieldUpdater\u3001AtomicIntegerFieldUpdater,AtomicReferenceFieldUpdater
\n\u89e3\u51b3 ABA \u95ee\u9898\u7684\u539f\u5b50\u7c7b\uff1aAtomicMarkableReference\uff08\u901a\u8fc7\u5f15\u5165\u4e00\u4e2abooolean\u6765\u53cd\u6620\u4e2d\u95f4\u6709\u6ca1\u6709\u53d8\u8fc7\uff09\uff0cAtomicStampedReference\uff08\u901a\u8fc7\u5f15\u5165\u4e00\u4e2aint\u7d2f\u52a0\u6765\u53cd\u6620\u4e2d\u95f4\u6709\u6ca1\u6709\u53d8\u8fc7\uff09<\/p>\n","protected":false},"excerpt":{"rendered":"
\u539f\u5b50\u64cd\u4f5c\uff1a\u4e00\u4e2a\u6216\u591a\u4e2a\u64cd\u4f5c\u5728 CPU \u6267\u884c\u8fc7\u7a0b\u4e2d\u4e0d\u88ab\u4e2d\u65ad\u7684\u7279\u6027 \u5f53\u6211\u4eec\u8bf4\u539f\u5b50\u64cd\u4f5c\u65f6\uff0c\u9700\u8981\u5206\u6e05\u695a\u9488\u5bf9\u7684\u662f GPU\u6307 […]<\/p>\n","protected":false},"author":8,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[99],"tags":[],"class_list":["post-8908","post","type-post","status-publish","format-standard","hentry","category-javabase"],"_links":{"self":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/8908","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/comments?post=8908"}],"version-history":[{"count":1,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/8908\/revisions"}],"predecessor-version":[{"id":8909,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/8908\/revisions\/8909"}],"wp:attachment":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/media?parent=8908"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/categories?post=8908"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/tags?post=8908"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}