Warum ist std::mutex in Visual C++ so viel schlimmer als std::shared_mutex? ⇐ C++

[Anonymous]

Führte Folgendes in Visual Studio 2022 im Release-Modus aus:

Code: Select all

#include 
#include 
#include 
#include 

std::mutex mx;
std::shared_mutex smx;

constexpr int N = 100'000'000;

int main()
{
auto t1 = std::chrono::steady_clock::now();
for (int i = 0; i != N; i++)
{
std::unique_lock l{ mx };
}
auto t2 = std::chrono::steady_clock::now();
for (int i = 0; i != N; i++)
{
std::unique_lock l{ smx };
}
auto t3 = std::chrono::steady_clock::now();

auto d1 = std::chrono::duration_cast(t2 - t1);
auto d2 = std::chrono::duration_cast(t3 - t2);

std::cout