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

On any sane implementation, the cost of thread creation should be proportional to the number of system calls it involves, and on the same order of magnitude as familiar system calls like open and read. Some casual measurements on my system showed pthread_create taking about twice as much time as open("/dev/null", O_RDWR), which is very expensive relative to pure computation but very cheap relative to any IO or other operations which would involve switching between user and kernel space.