{"id":7436,"date":"2026-07-22T12:23:56","date_gmt":"2026-07-22T04:23:56","guid":{"rendered":"https:\/\/i007.cc\/wordpress\/?p=7436"},"modified":"2026-07-22T12:23:56","modified_gmt":"2026-07-22T04:23:56","slug":"c-%e6%80%a7%e8%83%bd%e6%b5%8b%e9%87%8f%e5%b7%a5%e5%85%b7%e5%85%a8%e6%99%af","status":"publish","type":"post","link":"https:\/\/i007.cc\/wordpress\/archives\/7436","title":{"rendered":"C++ \u6027\u80fd\u6d4b\u91cf\u5de5\u5177\u5168\u666f"},"content":{"rendered":"

<\/h3>\n
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\ud83d\udd37 \u4e00\u3001\u6309\u573a\u666f\u5206\u7c7b<\/h3>\n
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\u5fae\u89c2\u6d4b\u91cf\uff08\u5355\u884c\u4ee3\u7801\/\u51fd\u6570\u7ea7\uff09  \u2192  Chrono \u8ba1\u65f6\u3001Google Benchmark\r\n\u5b8f\u89c2\u6027\u80fd\u5206\u6790\uff08\u627e\u74f6\u9888\uff09        \u2192  perf\u3001gprof\u3001Valgrind\/Callgrind\r\n\u5185\u5b58\u95ee\u9898\u6392\u67e5                  \u2192  Valgrind\/Memcheck\u3001AddressSanitizer\r\n\u53ef\u89c6\u5316\u5206\u6790                    \u2192  perf + FlameGraph\u3001VTune<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
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\ud83d\udd37 \u4e8c\u3001\u6700\u57fa\u7840\uff1astd::chrono<\/code> \u624b\u52a8\u8ba1\u65f6<\/h3>\n
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cpp<\/div>\n
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#include <chrono>\r\n#include <iostream>\r\n\r\nvoid heavyFunction() {\r\n    std::vector<int> v(1000000);\r\n    std::iota(v.begin(), v.end(), 0);\r\n    std::sort(v.rbegin(), v.rend());\r\n}\r\n\r\nint main() {\r\n    auto start = std::chrono::high_resolution_clock::now();\r\n    \r\n    heavyFunction();\r\n    \r\n    auto end = std::chrono::high_resolution_clock::now();\r\n    auto duration = std::chrono::duration_cast<std::chrono::microseconds>(end - start);\r\n    \r\n    std::cout << \"\u8017\u65f6: \" << duration.count() << \" \u5fae\u79d2\" << std::endl;\r\n}<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
\u26a0\ufe0f \u5e38\u89c1\u9677\u9631\uff1a\u7f16\u8bd1\u5668\u4f18\u5316\u628a\u4ee3\u7801”\u4f18\u5316\u6ca1\u4e86”<\/h4>\n
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cpp<\/div>\n
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auto start = std::chrono::high_resolution_clock::now();\r\nint result = expensiveComputation();\r\nauto end = std::chrono::high_resolution_clock::now();\r\n\/\/ \u274c \u5982\u679c result \u6ca1\u88ab\u7528\u5230\uff0c\u7f16\u8bd1\u5668\u53ef\u80fd\u76f4\u63a5\u628a\u6574\u4e2a\u8ba1\u7b97\u5220\u6389\uff01<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
\u89e3\u51b3\uff1a\u7528 volatile<\/code> \u6216\u786e\u4fdd\u7ed3\u679c\u88ab\u4f7f\u7528\uff1a<\/p>\n
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cpp<\/div>\n
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volatile int result = expensiveComputation();  \/\/ \u963b\u6b62\u4f18\u5316\u6389\r\n\/\/ \u6216\u8005\r\nstd::cout << result;  \/\/ \u786e\u4fdd\u7f16\u8bd1\u5668\u4e0d\u80fd\u4f18\u5316\u6389\u8ba1\u7b97<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
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\ud83d\udd37 \u4e09\u3001\u4e13\u4e1a\u57fa\u51c6\u6d4b\u8bd5\uff1aGoogle Benchmark<\/h3>\n
chrono<\/code> \u624b\u52a8\u8ba1\u65f6\u4e0d\u53ef\u9760<\/strong>\uff08\u53ea\u8dd1\u4e00\u6b21\uff0c\u53d7\u7cfb\u7edf\u6296\u52a8\u5f71\u54cd\u5f88\u5927\uff09\u3002\u751f\u4ea7\u7ea7\u505a\u6cd5\u662f\u7528\u4e13\u95e8\u7684\u57fa\u51c6\u6d4b\u8bd5\u5e93\uff0c\u81ea\u52a8\u591a\u6b21\u8fd0\u884c\u3001\u7edf\u8ba1\u3001\u6d88\u9664\u566a\u58f0\u3002<\/p>\n
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cpp<\/div>\n
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#include <benchmark\/benchmark.h>\r\n\r\nstatic void BM_VectorPushBack(benchmark::State& state) {\r\n    for (auto _ : state) {        \/\/ \u81ea\u52a8\u5faa\u73af\u591a\u6b21\uff0c\u76f4\u5230\u7edf\u8ba1\u7a33\u5b9a\r\n        std::vector<int> v;\r\n        for (int i = 0; i < 1000; i++) {\r\n            v.push_back(i);\r\n        }\r\n        benchmark::DoNotOptimize(v);  \/\/ \u9632\u6b62\u7f16\u8bd1\u5668\u4f18\u5316\u6389\r\n    }\r\n}\r\nBENCHMARK(BM_VectorPushBack);\r\n\r\nstatic void BM_VectorReserve(benchmark::State& state) {\r\n    for (auto _ : state) {\r\n        std::vector<int> v;\r\n        v.reserve(1000);   \/\/ \u5bf9\u6bd4\uff1a\u9884\u5206\u914d vs \u4e0d\u9884\u5206\u914d\r\n        for (int i = 0; i < 1000; i++) {\r\n            v.push_back(i);\r\n        }\r\n        benchmark::DoNotOptimize(v);\r\n    }\r\n}\r\nBENCHMARK(BM_VectorReserve);\r\n\r\nBENCHMARK_MAIN();<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
\u8f93\u51fa\u793a\u4f8b\uff1a<\/p>\n
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Benchmark                  Time             CPU   Iterations\r\nBM_VectorPushBack       3245 ns         3240 ns       215000\r\nBM_VectorReserve        1820 ns         1818 ns       384000<\/pre>\n
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\u4e00\u773c\u770b\u51fa<\/strong>\uff1areserve()<\/code> \u9884\u5206\u914d\u8ba9\u6027\u80fd\u63d0\u5347\u8fd1\u4e00\u500d\u2014\u2014\u8fd9\u6b63\u662f\u57fa\u51c6\u6d4b\u8bd5\u7684\u4ef7\u503c\uff1a\u7528\u6570\u636e\u8bf4\u8bdd\uff0c\u800c\u4e0d\u662f\u731c<\/strong>\u3002<\/p>\n<\/blockquote>\n
\u8fdb\u9636\uff1a\u53c2\u6570\u5316\u6d4b\u8bd5\u4e0d\u540c\u8f93\u5165\u89c4\u6a21<\/h4>\n
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cpp<\/div>\n
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static void BM_Sort(benchmark::State& state) {\r\n    int n = state.range(0);   \/\/ \u6d4b\u8bd5\u4e0d\u540c\u89c4\u6a21\r\n    std::vector<int> v(n);\r\n    for (auto _ : state) {\r\n        std::iota(v.begin(), v.end(), 0);\r\n        std::sort(v.rbegin(), v.rend());\r\n    }\r\n}\r\nBENCHMARK(BM_Sort)->Arg(1000)->Arg(10000)->Arg(100000);\r\n\/\/ \u4e00\u6b21\u6027\u770b\u5230\u4e0d\u540c\u89c4\u6a21\u4e0b\u7684\u6027\u80fd\u66f2\u7ebf\uff0c\u5224\u65ad\u7b97\u6cd5\u590d\u6742\u5ea6\u662f\u5426\u7b26\u5408\u9884\u671f<\/pre>\n
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\ud83d\udd37 \u56db\u3001\u7cfb\u7edf\u7ea7\u6027\u80fd\u5256\u6790\uff1aperf<\/code>\uff08Linux\uff09<\/h3>\n
chrono<\/code>\/Benchmark \u544a\u8bc9\u4f60”\u6162<\/strong>“\uff0c\u4f46\u4e0d\u77e5\u9053”\u4e3a\u4ec0\u4e48\u6162\u3001\u6162\u5728\u54ea\u4e00\u884c<\/strong>“\u3002perf<\/code> \u80fd\u7cbe\u786e\u5b9a\u4f4d\u70ed\u70b9\u51fd\u6570\u3002<\/p>\n
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bash<\/div>\n
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# \u7f16\u8bd1\u65f6\u4fdd\u7559\u8c03\u8bd5\u4fe1\u606f\uff08\u5173\u952e\uff01\u5426\u5219\u770b\u4e0d\u5230\u51fd\u6570\u540d\/\u884c\u53f7\uff09\r\ng++ -O2 -g myprogram.cpp -o myprogram\r\n\r\n# \u91c7\u6837\u8fd0\u884c\u65f6\u7684\u6027\u80fd\u6570\u636e\r\nperf record -g .\/myprogram\r\n\r\n# \u67e5\u770b\u70ed\u70b9\u62a5\u544a\r\nperf report<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
\u8f93\u51fa\u7c7b\u4f3c\uff1a<\/p>\n
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Overhead  Symbol\r\n  45.2%   sortAlgorithm()      \u2190 45%\u7684\u65f6\u95f4\u82b1\u5728\u8fd9\u91cc\uff01\r\n  22.1%   memoryAllocation()\r\n  12.3%   std::vector::push_back<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
\u706b\u7130\u56fe\u53ef\u89c6\u5316\uff08\u66f4\u76f4\u89c2\uff09<\/h4>\n
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bash<\/div>\n
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git clone https:\/\/github.com\/brendangregg\/FlameGraph\r\n\r\nperf record -g .\/myprogram\r\nperf script | .\/FlameGraph\/stackcollapse-perf.pl | .\/FlameGraph\/flamegraph.pl > flame.svg<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
\u706b\u7130\u56fe\u4e2d\uff0c\u6a2a\u5411\u5bbd\u5ea6 = \u8017\u65f6\u5360\u6bd4<\/strong>\uff0c\u4e00\u773c\u770b\u51fa\u54ea\u4e2a\u51fd\u6570\u8c03\u7528\u94fe\u6700\u8017\u65f6\u3002<\/p>\n
\n
\ud83d\udd37 \u4e94\u3001\u5185\u5b58\u95ee\u9898\u6392\u67e5\uff1aValgrind<\/h3>\n
Memcheck\uff1a\u68c0\u6d4b\u5185\u5b58\u6cc4\u6f0f\u3001\u8d8a\u754c\u8bbf\u95ee<\/h4>\n
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bash<\/div>\n
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g++ -g myprogram.cpp -o myprogram\r\nvalgrind --leak-check=full .\/myprogram<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
\u8f93\u51fa\uff1a<\/p>\n
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==12345== HEAP SUMMARY:\r\n==12345==     in use at exit: 40 bytes in 1 blocks\r\n==12345== LEAK SUMMARY:\r\n==12345==    definitely lost: 40 bytes in 1 blocks\r\n==12345==    at 0x... malloc\r\n==12345==    by 0x... main (myprogram.cpp:15)   \u2190 \u7cbe\u786e\u5b9a\u4f4d\u6cc4\u6f0f\u884c\u53f7\uff01<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
Callgrind\uff1a\u51fd\u6570\u8c03\u7528\u6b21\u6570 + \u8017\u65f6\u5206\u6790<\/h4>\n
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bash<\/div>\n
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valgrind --tool=callgrind .\/myprogram\r\nkcachegrind callgrind.out.12345   # \u56fe\u5f62\u754c\u9762\u67e5\u770b\u8c03\u7528\u56fe<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
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\u7f3a\u70b9<\/strong>\uff1aValgrind \u4f1a\u8ba9\u7a0b\u5e8f\u6162 10-50 \u500d\uff08\u6a21\u62df\u6267\u884c\u73af\u5883\uff09\uff0c\u4e0d\u9002\u5408\u5b9e\u65f6\u6027\u80fd\u6d4b\u8bd5\uff0c\u53ea\u9002\u5408”\u627e\u95ee\u9898”\u3002<\/p>\n<\/blockquote>\n
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\ud83d\udd37 \u516d\u3001\u66f4\u8f7b\u91cf\u7684\u5185\u5b58\u68c0\u6d4b\uff1aAddressSanitizer (ASan)<\/h3>\n
\u6bd4 Valgrind \u5feb\u5f97\u591a\uff08\u53ea\u6162 2 \u500d\u5de6\u53f3\uff09\uff0c\u7f16\u8bd1\u65f6\u542f\u7528\uff1a<\/p>\n
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bash<\/div>\n
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g++ -g -fsanitize=address myprogram.cpp -o myprogram\r\n.\/myprogram<\/pre>\n
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cpp<\/div>\n
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int main() {\r\n    int* p = new int[10];\r\n    p[10] = 5;  \/\/ \u8d8a\u754c\u5199\u5165\r\n    delete[] p;\r\n}<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
\u8fd0\u884c\u65f6\u76f4\u63a5\u62a5\u9519\u5e76\u5b9a\u4f4d\uff1a<\/p>\n
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==12345==ERROR: AddressSanitizer: heap-buffer-overflow\r\n    #0 main (myprogram.cpp:3)   \u2190 \u7cbe\u786e\u6307\u51fa\u7b2c3\u884c\u8d8a\u754c<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
\u8fd8\u6709\u914d\u5957\u7684\uff1a<\/p>\n
    \n
  • -fsanitize=thread<\/code>\uff08TSan<\/strong>\uff09\uff1a\u68c0\u6d4b\u6570\u636e\u7ade\u4e89\uff08\u591a\u7ebf\u7a0b bug \u795e\u5668\uff09<\/li>\n
  • -fsanitize=undefined<\/code>\uff08UBSan<\/strong>\uff09\uff1a\u68c0\u6d4b\u672a\u5b9a\u4e49\u884c\u4e3a\uff08\u6574\u6570\u6ea2\u51fa\u7b49\uff09<\/li>\n<\/ul>\n
    \n
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    <\/div>\n<\/div>\n
    bash<\/div>\n
    \n
    # \u68c0\u6d4b\u591a\u7ebf\u7a0b\u6570\u636e\u7ade\u4e89\r\ng++ -g -fsanitize=thread myprogram.cpp -o myprogram<\/pre>\n
     <\/p>\n<\/div>\n<\/div>\n
    \n
    \ud83d\udd37 \u4e03\u3001CPU \u7f13\u5b58\/\u6307\u4ee4\u7ea7\u5206\u6790\uff1aIntel VTune\uff08\u66f4\u4e13\u4e1a\u7ea7\uff09<\/h3>\n
    \u9002\u5408\u6781\u81f4\u4f18\u5316\u573a\u666f\uff08\u9ad8\u9891\u4ea4\u6613\u3001\u6e38\u620f\u5f15\u64ce\uff09\uff0c\u80fd\u5206\u6790\uff1a<\/p>\n
      \n
    • CPU \u7f13\u5b58\u547d\u4e2d\u7387\uff08L1\/L2\/L3 miss\uff09<\/li>\n
    • \u5206\u652f\u9884\u6d4b\u5931\u8d25\u7387<\/li>\n
    • SIMD \u5411\u91cf\u5316\u662f\u5426\u751f\u6548<\/li>\n<\/ul>\n
      \n
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      <\/div>\n<\/div>\n
      bash<\/div>\n
      \n
      vtune -collect hotspots .\/myprogram<\/pre>\n
       <\/p>\n<\/div>\n<\/div>\n
      \u56fe\u5f62\u754c\u9762\u5c55\u793a\u5177\u4f53\u5230\u6c47\u7f16\u6307\u4ee4\u7ea7\u522b<\/strong>\u7684\u8017\u65f6\u5206\u5e03\uff0c\u9002\u5408”\u538b\u69a8\u6700\u540e5%\u6027\u80fd”\u7684\u573a\u666f\u3002<\/p>\n
      \n
      \ud83d\udd37 \u5de5\u5177\u9009\u62e9\u901f\u67e5\u8868<\/h3>\n
      \n\n\n\n\n\n\n\n\n\n\n
      \u76ee\u6807<\/th>\n\u5de5\u5177<\/th>\n<\/tr>\n<\/thead>\n
      \u5feb\u901f\u770b\u67d0\u6bb5\u4ee3\u7801\u8017\u65f6<\/td>\nstd::chrono<\/code><\/td>\n<\/tr>\n
      \u4e25\u8c28\u5bf9\u6bd4\u4e0d\u540c\u5b9e\u73b0\u7684\u6027\u80fd<\/td>\nGoogle Benchmark<\/td>\n<\/tr>\n
      \u627e\u6574\u4e2a\u7a0b\u5e8f\u7684\u6027\u80fd\u74f6\u9888<\/td>\nperf<\/code> + \u706b\u7130\u56fe<\/td>\n<\/tr>\n
      \u5185\u5b58\u6cc4\u6f0f \/ \u8d8a\u754c<\/td>\nValgrind \/ AddressSanitizer<\/td>\n<\/tr>\n
      \u591a\u7ebf\u7a0b\u6570\u636e\u7ade\u4e89<\/td>\nThreadSanitizer<\/td>\n<\/tr>\n
      \u6781\u81f4\u5e95\u5c42\u4f18\u5316\uff08\u7f13\u5b58\/\u6307\u4ee4\uff09<\/td>\nIntel VTune<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n
      \n
      \ud83d\udd37 \u5b9e\u6218\u6d41\u7a0b\u5efa\u8bae<\/h3>\n
      \n
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      <\/div>\n<\/div>\n
      \n
      1. \u5148\u7528 std::chrono \u7c97\u7565\u5b9a\u4f4d\"\u54ea\u4e2a\u529f\u80fd\u6162\"\r\n        \u2193\r\n2. \u7528 perf + \u706b\u7130\u56fe \u627e\u5230\u5177\u4f53\"\u54ea\u4e2a\u51fd\u6570\/\u54ea\u884c\u4ee3\u7801\"\u662f\u74f6\u9888\r\n        \u2193\r\n3. \u9488\u5bf9\u74f6\u9888\u5199 Google Benchmark\uff0c\u91cf\u5316\u5bf9\u6bd4\u4f18\u5316\u524d\u540e\u6548\u679c\r\n        \u2193\r\n4. \u7528 ASan\/TSan \u786e\u4fdd\u4f18\u5316\u6ca1\u5f15\u5165\u5185\u5b58\/\u5e76\u53d1 bug<\/pre>\n
       <\/p>\n<\/div>\n<\/div>\n
      \n
      \u4e00\u53e5\u8bdd\u603b\u7ed3<\/h3>\n
      \n
      chrono<\/code> \u7528\u4e8e”\u77e5\u9053\u6162\u4e0d\u6162”\uff0cperf<\/code>\/\u706b\u7130\u56fe\u7528\u4e8e”\u77e5\u9053\u6162\u5728\u54ea”\uff0cGoogle Benchmark \u7528\u4e8e”\u8bc1\u660e\u4f18\u5316\u6709\u6ca1\u6709\u7528”\uff0cValgrind\/Sanitizer \u7528\u4e8e”\u786e\u4fdd\u4f18\u5316\u6ca1\u641e\u51fa\u65b0bug”<\/strong> \u2014\u2014 \u56db\u8005\u914d\u5408\uff0c\u624d\u662f\u5b8c\u6574\u7684\u6027\u80fd\u4f18\u5316\u95ed\u73af\u3002<\/p>\n<\/blockquote>\n
      \u60f3\u6df1\u5165\u54ea\u4e2a\u65b9\u5411\uff1f\u6bd4\u5982 cache-friendly \u6570\u636e\u7ed3\u6784\u8bbe\u8ba1<\/strong>\uff08\u5982\u4f55\u5199\u51fa CPU \u7f13\u5b58\u53cb\u597d\u7684\u4ee3\u7801\uff09\u6216\u8005 SIMD \u5411\u91cf\u5316\u4f18\u5316<\/strong>\uff1f<\/p>\n","protected":false},"excerpt":{"rendered":"
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