std::set::upper_bound与std::upper_bound性能差距有多大?

测试

#include <benchmark/benchmark.h>
#include <set>
#include <stdlib.h>

void initStdSet(std::set<int> &container){
   
   
    // std::set<int> bkt;
    for(int i = 0; i != 10000; ++i){
   
   
        container.emplace(rand());
    }
}

// base
static void BM_CXXStdSetCreation(benchmark::State& state){
   
   
    std::set<int> bkt;
    initStdSet(bkt);
    for(auto _ : state){