{"id":451,"date":"2013-11-01T17:38:48","date_gmt":"2013-11-01T09:38:48","guid":{"rendered":"http:\/\/www.gpfeng.com\/?p=451"},"modified":"2013-11-01T19:38:45","modified_gmt":"2013-11-01T11:38:45","slug":"pthread-mutex%e4%b8%8egcc-atomic%e6%80%a7%e8%83%bd%e6%b5%8b%e8%af%95","status":"publish","type":"post","link":"http:\/\/www.gpfeng.com\/?p=451","title":{"rendered":"Pthread mutex\u4e0eGCC atomic\u6027\u80fd\u6d4b\u8bd5"},"content":{"rendered":"<h3>\u95ee\u9898\u80cc\u666f<\/h3>\n<p>\u4e4b\u524d\u5bf9\u8fd9\u4e00\u5757\u53ea\u6709\u4e00\u4e2a\u521d\u6b65\u7684\u7406\u89e3\uff0c\u9605\u8bfb\u8fc7\u4e00\u4e9b\u6587\u7ae0\uff0c\u5927\u6982\u77e5\u9053pthread\u4e2dmutex\u4e00\u6b21\u52a0\u9501\u65f6\u95f4\u572810~100ns\u4e4b\u95f4\uff0c\u76f4\u89c9\u4e0a\u8ba4\u4e3a\u8fd9\u4e2a\u6548\u7387\u975e\u5e38\u9ad8\u4e86\uff0c\u6700\u8fd1\u505aMySQL\u9ad8\u5e76\u53d1\u4f18\u5316\u5de5\u4f5c\u540e\uff0c\u53d1\u73b0\u81ea\u5df1\u77e5\u9053\u7684\u592a\u5c11\uff0c\u4ee5\u81f4\u6d6a\u8d39\u4e86\u4e0d\u5c11\u65f6\u95f4\uff0c\u9042\u51b3\u5b9a\u901a\u8fc7\u6d4b\u8bd5\u603b\u7ed3\u4e00\u4e0b\u6700\u8fd1\u5b66\u4e60\u5230\u7684\u4e1c\u897f<\/p>\n<p>mutex\u7684\u4e3b\u8981\u4f5c\u7528\u662f\u4fdd\u8bc1\u539f\u5b50\u6027\u64cd\u4f5c\uff0cpthread\u5b9e\u73b0\u63d0\u4f9b\u7684\u4e00\u5957api\u975e\u5e38\u7b80\u6d01\uff0c\u5bf9\u4e8e\u4e00\u822c\u7684\u5e94\u7528\u80af\u5b9a\u662f\u591f\u4e86\uff0c\u4f46\u662f\u5bf9\u4e8eDatabase\u8fd9\u79cd\u5bf9\u6027\u80fd\u6709\u53d8\u6001\u8981\u6c42\u7684\u7cfb\u7edf\uff0c\u5c24\u5176\u662f\u5728\u9ad8\u5e76\u53d1\u4e0b\uff0c\u9700\u8981\u8fdb\u4e00\u6b65\u4f18\u5316\uff0c\u8fd9\u65f6\u9700\u8981\u7528\u5230gcc\u63d0\u4f9b\u7684__sync_xxx_and_fetch\u7cfb\u5217\u51fd\u6570\u4e86\uff0c\u5177\u4f53\u53c2\u8003\uff1a<a href=\"http:\/\/pic.dhe.ibm.com\/infocenter\/compbg\/v121v141\/index.jsp?topic=%2Fcom.ibm.xlcpp121.bg.doc%2Fcompiler_ref%2Fbif_gcc_atomic_lock_test_set.html\">GCC Atomic Memory Access and built-in functions<\/a>\uff0c\u8fd9\u7cfb\u5217\u51fd\u6570\u4f7f\u7528\u5185\u5b58\u5c4f\u969c\u4fdd\u8bc1\u5bf9\u5185\u5b58\u5355\u5143\u7684\u539f\u5b50\u64cd\u4f5c\uff0c\u6027\u80fd\u8f83pthread\u597d\uff0c\u672c\u6587\u901a\u8fc7\u4e00\u7cfb\u5217\u6d4b\u8bd5\u5f97\u51fa\u5b9a\u91cf\u7ed3\u8bba<br \/>\n<!--more--><\/p>\n<h3>\u6d4b\u8bd5\u573a\u666f<\/h3>\n<p>\u56db\u4e2a\u57fa\u672c\u573a\u666f\uff0c\u901a\u8fc7\u4e0d\u540c\u7ebf\u7a0b\u6570\u5f97\u5230\u591a\u7ec4\u6d4b\u8bd5\u6570\u636e<br \/>\n<strong>\u573a\u666f\u4e00<\/strong>\uff1apthread_mutex_lock\/pthread_mutex_unlock\u4e4b\u95f4\u4e0d\u6267\u884c\u4efb\u4f55\u4ee3\u7801<br \/>\n<strong>\u573a\u666f\u4e8c<\/strong>\uff1apthread_mutex_lock\/pthread_mutex_unlock\u4e4b\u95f4\u6267\u884c\u4e00\u6b21sum++\u64cd\u4f5c<br \/>\n<strong>\u573a\u666f\u4e09<\/strong>\uff1apthread_mutex_lock\/pthread_mutex_unlock\u4e4b\u95f4\u6267\u884c\u591a\u53e5\u4ee3\u7801<br \/>\n<strong>\u573a\u666f\u56db<\/strong>\uff1a\u4f7f\u7528__sync_add_and_fetch\u539f\u5b50\u6267\u884csum++\u64cd\u4f5c<\/p>\n<h3>\u786c\u4ef6\u73af\u5883<\/h3>\n<p>Intel(R) Xeon(R) CPU           E5420  @ 2.50GHz<\/p>\n<pre lang=\"shell\">\r\nArchitecture:          x86_64\r\nCPU op-mode(s):        32-bit, 64-bit\r\nByte Order:            Little Endian\r\nCPU(s):                8\r\nOn-line CPU(s) list:   0-7\r\nThread(s) per core:    1\r\nCore(s) per socket:    4\r\nCPU socket(s):         2\r\nNUMA node(s):          1\r\nVendor ID:             GenuineIntel\r\nCPU family:            6\r\nModel:                 23\r\nStepping:              10\r\nCPU MHz:               2493.847\r\nBogoMIPS:              4987.52\r\nVirtualization:        VT-x\r\nL1d cache:             32K\r\nL1i cache:             32K\r\nL2 cache:              6144K\r\nNUMA node0 CPU(s):     0-7\r\n<\/pre>\n<h3>\u6d4b\u8bd5\u4ee3\u7801<\/h3>\n<pre lang=\"c\">\r\n#include <stdio.h>\r\n#include <stdlib.h>\r\n#include <pthread.h>\r\n#include <time.h>\r\n\r\n#define MAX_THREADS 10000\r\n\r\nlong sum = 0;\r\nlong sum1 = 0;\r\n\r\npthread_barrier_t barr;\r\npthread_mutex_t   lock = PTHREAD_MUTEX_INITIALIZER;\r\n\r\nvoid *thread_add_func0(void * param)\r\n{\r\n  pthread_barrier_wait(&barr);\r\n  int i;\r\n  for (i = 0; i < *((int*)param); i++)\r\n  { \r\n    pthread_mutex_lock(&#038;lock);\r\n    pthread_mutex_unlock(&#038;lock);\r\n  }\r\n}\r\n\r\nvoid *thread_add_func1(void * param)\r\n{\r\n  pthread_barrier_wait(&#038;barr);\r\n  int i;\r\n  for (i = 0; i < *((int*)param); i++)\r\n  { \r\n    pthread_mutex_lock(&#038;lock);\r\n    sum++;\r\n    pthread_mutex_unlock(&#038;lock);\r\n  }\r\n}\r\n\r\nvoid *thread_add_func2(void * param)\r\n{\r\n  pthread_barrier_wait(&#038;barr);\r\n  int i;\r\n  int j = 0;\r\n  for (i = 0; i < *((int*)param); i++)\r\n  { \r\n    pthread_mutex_lock(&#038;lock);\r\n    if (j == 0)\r\n    {\r\n      sum += 3;\r\n      j = 1;\r\n    } \r\n    else\r\n    {\r\n      sum -= 1;\r\n      j = 0;\r\n    }\r\n    pthread_mutex_unlock(&#038;lock);\r\n  }\r\n}\r\n\r\nvoid *thread_add_func3(void * param)\r\n{\r\n  pthread_barrier_wait(&#038;barr);\r\n  int i;\r\n  for (i = 0; i < *((int*)param); i++)\r\n    __sync_add_and_fetch(&#038;sum, 1);\r\n}\r\n\r\nvoid test_func(void* (*func)(void *), int threads, int loop, const char *name)\r\n{\r\n  pthread_barrier_init(&#038;barr, NULL, threads + 1);\r\n\r\n  pthread_t tids[MAX_THREADS];\r\n\r\n  int i;\r\n  sum = 0;\r\n\r\n  for (i = 0; i < threads; i++)\r\n    pthread_create(&#038;tids[i], NULL, func, (void*)&#038;loop);\r\n\r\n  pthread_barrier_wait(&#038;barr);\r\n  time_t start = time(NULL);\r\n\r\n  for (i = 0; i < threads; i++)\r\n    pthread_join(tids[i], NULL);\r\n\r\n  printf(\"%s:\\tsum: %d, time: %d seconds\\n\", \r\n         name, sum, time(NULL) - start);\r\n}\r\n\r\nint main(int argc, char *argv[])\r\n{\r\n  if (argc < 2)\r\n    return 1;\r\n\r\n  int threads = atoi(argv[1]);\r\n\r\n  if (threads <=0 || threads > MAX_THREADS)\r\n    return 1;\r\n\r\n  int loop = 1000000000 \/ threads;\r\n\r\n  printf(\"threads: %d, loops per thread: %d\\n\", threads, loop);\r\n  \r\n  test_func(thread_add_func0, threads, loop, \"mutex-void\");\r\n  test_func(thread_add_func1, threads, loop, \"mutex-sum\");\r\n  test_func(thread_add_func2, threads, loop, \"mutex-sum-2\");\r\n  test_func(thread_add_func3, threads, loop, \"gcc atomic add\");\r\n\r\n  printf(\"\\n\");\r\n\r\n  return 0;\r\n}\r\n<\/pre>\n<h3>\u6d4b\u8bd5\u7ed3\u679c<\/h3>\n<pre lang=\"shell\">\r\n.\/a.out 1 && .\/a.out 10 && .\/a.out 100 && .\/a.out 1000 && .\/a.out 10000\r\nthreads: 1, loops per thread: 1000000000\r\nmutex-void:     sum: 0, time: 38 seconds\r\nmutex-sum:      sum: 1000000000, time: 39 seconds\r\nmutex-sum-2:    sum: 1000000000, time: 39 seconds\r\ngcc atomic add: sum: 1000000000, time: 16 seconds\r\n\r\nthreads: 10, loops per thread: 100000000\r\nmutex-void:     sum: 0, time: 115 seconds\r\nmutex-sum:      sum: 1000000000, time: 118 seconds\r\nmutex-sum-2:    sum: 1000000000, time: 122 seconds\r\ngcc atomic add: sum: 1000000000, time: 28 seconds\r\n\r\nthreads: 100, loops per thread: 10000000\r\nmutex-void:     sum: 0, time: 104 seconds\r\nmutex-sum:      sum: 1000000000, time: 107 seconds\r\nmutex-sum-2:    sum: 1000000000, time: 110 seconds\r\ngcc atomic add: sum: 1000000000, time: 27 seconds\r\n\r\nthreads: 1000, loops per thread: 1000000\r\nmutex-void:     sum: 0, time: 102 seconds\r\nmutex-sum:      sum: 1000000000, time: 105 seconds\r\nmutex-sum-2:    sum: 1000000000, time: 109 seconds\r\ngcc atomic add: sum: 1000000000, time: 27 seconds\r\n\r\nthreads: 10000, loops per thread: 100000\r\nmutex-void:     sum: 0, time: 94 seconds\r\nmutex-sum:      sum: 1000000000, time: 96 seconds\r\nmutex-sum-2:    sum: 1000000000, time: 101 seconds\r\ngcc atomic add: sum: 1000000000, time: 27 seconds\r\n<\/pre>\n<h3>\u7ed3\u679c\u5206\u6790<\/h3>\n<p>1. \u5355\u7ebf\u7a0b\u72b6\u6001\u4e0bpthread\u5e93\u4e00\u6b21lock+unlock\u5927\u6982\u6d88\u801740ns<br \/>\n2. \u9664\u4e86\u5355\u7ebf\u7a0b\u5916\uff0c\u5176\u5b83\u4e09\u7ec4\u6570\u636e\u57fa\u672c\u76f8\u540c\uff0c\u8fd9\u8bf4\u660epthread\u5e93\u5728\u5e76\u53d1\u589e\u52a0\u65f6\u5e76\u4e0d\u4f1a\u6027\u80fd\u6025\u5267\u4e0b\u964d\uff0c\u4e00\u6b21lock+unlock\u6d88\u8017100ns\u5de6\u53f3<br \/>\n3. mutex-void\/mutex-sum\/mutex-sum-2\u7ed3\u679c\u5bf9\u8fb9\u53ef\u4ee5\u770b\u51fa\uff0c\u5185\u5b58\u5b58\u53d6\u6307\u4ee4\u6d88\u8017\u65f6\u95f4\u5927\u6982\u662fpthread\u4e00\u6b21lock+unlock\u76841\/30<br \/>\n4. GCC atomic\u64cd\u4f5c\u6548\u7387\u975e\u5e38\u9ad8\uff0c\u5c24\u5176\u662f\u5728\u5e76\u53d1\u4e0b\u73af\u5883\u4e0b\uff0c\u6027\u80fd\u5927\u6982\u662fpthread\u5e93\u76844~5\u500d<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u95ee\u9898\u80cc\u666f \u4e4b\u524d\u5bf9\u8fd9\u4e00\u5757\u53ea\u6709\u4e00\u4e2a\u521d\u6b65\u7684\u7406\u89e3\uff0c\u9605\u8bfb\u8fc7\u4e00\u4e9b\u6587\u7ae0\uff0c\u5927\u6982\u77e5\u9053pthread\u4e2dmutex\u4e00\u6b21\u52a0\u9501\u65f6\u95f4\u572810 &hellip; <a href=\"http:\/\/www.gpfeng.com\/?p=451\" class=\"more-link\">\u7ee7\u7eed\u9605\u8bfb<span class=\"screen-reader-text\">Pthread mutex\u4e0eGCC atomic\u6027\u80fd\u6d4b\u8bd5<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false}}},"categories":[2],"tags":[],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p3tPZp-7h","jetpack_sharing_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"http:\/\/www.gpfeng.com\/index.php?rest_route=\/wp\/v2\/posts\/451"}],"collection":[{"href":"http:\/\/www.gpfeng.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.gpfeng.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.gpfeng.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.gpfeng.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=451"}],"version-history":[{"count":7,"href":"http:\/\/www.gpfeng.com\/index.php?rest_route=\/wp\/v2\/posts\/451\/revisions"}],"predecessor-version":[{"id":459,"href":"http:\/\/www.gpfeng.com\/index.php?rest_route=\/wp\/v2\/posts\/451\/revisions\/459"}],"wp:attachment":[{"href":"http:\/\/www.gpfeng.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=451"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.gpfeng.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=451"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.gpfeng.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=451"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}