C++ main loop stutters occasionally

I encountered a problem where my game-loop stuttered approximating once a second (variable intervals). A single frame then takes over 60ms whereas all others require less than 1ms.

After simplifying a lot I ended with the following program which reproduces the bug. It only measures the frame time and reports it.

#include <iostream>
#include "windows.h"

int main()
{
    unsigned long long frequency, tic, toc;
    QueryPerformanceFrequency((LARGE_INTEGER*)&frequency);
    QueryPerformanceCounter((LARGE_INTEGER*)&tic);
    double deltaTime = 0.0;
    while( true )
    {
        //if(deltaTime > 0.01)
        std::cerr << deltaTime << std::endl;
        QueryPerformanceCounter((LARGE_INTEGER*)&toc);
        deltaTime = (toc - tic) / double(frequency);
        tic = toc;
        if(deltaTime < 0.01) deltaTime = 0.01;
    }
}

Again one frame in many is much slower than the others. Adding the if let the error vanish (cerr is never called then). My original problem didn't contain any cerr/cout. However, I consider this as a reproduction of the same error.

cerr is flushed in every iteration, so this is not what happens to create single slow frames. I know from a profiler (Very Sleepy) that the stream internally uses a lock/critical section, but this shouldn't change anything because the program is singlethreaded.

What causes single iterations to stall that much?