stl::vectorのパフォーマンス

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#include <iostream>
#include <vector>
#include <algorithm>
#include <boost/timer.hpp>

struct E {
    unsigned int id;
    unsigned char value[1024];
};

struct NonOptimize {
    NonOptimize(const size_t num) : n(num) { }

    inline void operator()() const {
        std::vector&lt;E&gt; v;
        for (size_t i = 0; i &lt; n; ++i) {
            E e = {i};
            v.push_back(e);
        }
    }

    const size_t n;
};

struct ConstructWithSize {
    ConstructWithSize(const size_t num) : n(num) { }

    inline void operator()() const {
        std::vector&lt;E&gt; v(n);
        for (size_t i = 0; i &lt; n; ++i) {
            E e = {i};
            v[i] = e;
        }
    }

    const size_t n;
};

struct Reserved {
    Reserved(const size_t num) : n(num) { }

    inline void operator()() const {
        std::vector&lt;E&gt; v;
        v.reserve(n);
        for (size_t i = 0; i &lt; n; ++i) {
            E e = {i};
            v.push_back(e);
        }
    }

    const size_t n;
};

template &lt;typename F&gt;
inline std::vector&lt;double&gt;&amp; mesure(F&amp; func, std::vector&lt;double&gt;* elapsed) {
    typedef std::vector&lt;double&gt; Results;
    boost::timer timer;

    for (Results::iterator i(elapsed-&gt;begin()), end(elapsed-&gt;end()); i != end; ++i) {
        timer.restart();
        func();
        *i = timer.elapsed();
    }
    return *elapsed;
}

std::ostream&amp; operator&lt;&lt;(std::ostream&amp; os, const std::vector&lt;double&gt;&amp; elapsed) {
    typedef std::vector&lt;double&gt; Results;
    Results::const_iterator max = std::max_element(elapsed.begin(), elapsed.end());
    Results::const_iterator min = std::min_element(elapsed.begin(), elapsed.end());
    double sum(0);;
    for (Results::const_iterator i(elapsed.begin()), end(elapsed.end()); i != end; ++i) {
        if (i != max &amp;&amp; i != min) {
            sum += *i;
        }
    }
    os &lt;&lt; "MAX: " &lt;&lt; *max &lt;&lt; ", MIN:" &lt;&lt; *min &lt;&lt; ", AVG:" &lt;&lt; (sum / (elapsed.size() - 2));
    return os;
}

int main(int argc, char **argv) {
    static const size_t NUM(50000);
    boost::timer timer;

    NonOptimize f1(NUM);
    ConstructWithSize f2(NUM);
    Reserved f3(NUM);

    std::cout &lt;&lt; argv[0] &lt;&lt; std::endl;
    std::vector&lt;double&gt; elapsed(10);
    std::cout &lt;&lt; mesure(f1, &amp;elapsed) &lt;&lt; std::endl;
    std::cout &lt;&lt; mesure(f2, &amp;elapsed) &lt;&lt; std::endl;
    std::cout &lt;&lt; mesure(f3, &amp;elapsed) &lt;&lt; std::endl;

    return 0;
}

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all: main_gnu main_llvm_gnu

main_gnu: main.cc
	g++ $(CXXFLAGS) $< -o $@

main_llvm_gnu: main.cc
	llvm-g++ $(CXXFLAGS) $< -o $@

.PHONY: clean
clean:
	@rm -fv main_gnu main_llvm_gnu

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$ make; ./main_gnu; ./main_llvm_gnu
g++ -O3 -Wall main.cc -o main_gnu
llvm-g++ -O3 -Wall main.cc -o main_llvm_gnu
./main_gnu
MAX: 0.29, MIN:0.26, AVG:0.27875
MAX: 0.18, MIN:0.14, AVG:0.15125
MAX: 0.13, MIN:0.11, AVG:0.1175
./main_llvm_gnu
MAX: 0.25, MIN:0.24, AVG:0.2425
MAX: 0.15, MIN:0.13, AVG:0.13875
MAX: 0.11, MIN:0.1, AVG:0.105