How much overhead is there when creating a thread?

Question

I just reviewed some really terrible code - code that sends messages on a serial port by creating a new thread to package and assemble the message in a new thread for every

Answer 1

It is indeed very system dependent, I tested @Nafnlaus code:

#include 

int main(int argc, char** argv)
{
  for (volatile int i = 0; i < 500000; i++)
    std::thread([](){}).detach();
  return 0;
}

On my Desktop Ryzen 5 2600:

windows 10, compiled with MSVC 2019 release adding std::chrono calls around it to time it. Idle (only Firefox with 217 tabs):

It took around 20 seconds (20.274, 19.910, 20.608) (also ~20 seconds with Firefox closed)

Ubuntu 18.04 compiled with:

g++ main.cpp -std=c++11 -lpthread -O3 -o thread

timed with:

time ./thread

It took around 5 seconds (5.595, 5.230, 5.297)

The same code on my raspberry pi 3B compiled with:

g++ main.cpp -std=c++11 -lpthread -O3 -o thread

timed with:

time ./thread

took around 15 seconds (16.225, 14.689, 16.235)