How to profile my C++ application on linux

Question

I would like to profile my c++ application on linux. I would like to find out how much time my application spent on CPU processing vs time spent on block by IO/being idle.

Answer 1

See this post.

And this post.

Basically, between the time the program starts and when it finishes, it has a call stack. During I/O, the stack terminates in a system call. During computation, it terminates in a typical instruction.

Either way, if you can sample the stack at random wall-clock times, you can see exactly why it's spending that time.

The only remaining point is - thousands of samples might give a sense of confidence, but they won't tell you much more than 10 or 20 samples will.