title: What does frame_dummy mean in the context of profiling?
body: <p>In the process of using gprof to profile a C++ program I've written, I've noticed that the vast majority of execution time is spent in the function "frame_dummy". More precisely, the first entry in the flat profile from the output of gprof shows 76.38% of sample time spent in and 24611191 calls to a function with name frame_dummy.</p>
  
  <p>In short, I am trying to understand both what frame_dummy refers to -- as I do not have any function named as such -- as well as what this means for my optimization efforts.</p>
  
  <p>Though it is unlikely to be relevant, I should add that this program is designed to solve Poisson's equation using the multigrid algorithm, and employs MPI to parallelize the task. However, though MPI function calls are present, the gprof output mentioned above is derived from running only a single process. I should also note that my program has no dependencies aside from MPI and was compiled with g++ 4.6.1.</p>