title: When writing openCL code, how does it perform on a single-core machine without a GPU?
body: <p>Hey all,
  I Am currently porting a raytracer from FORTRAN 77 to C for a research project.</p>
  
  <p>After having ported the essentials, the question is how we proceed to parallelization.<br>
  In the lab, I have access to a couple of different Opteron machines, with between 2 and 8 cores, but no GPUs (for now).
  We are running 64b gentoo.</p>
  
  <p>A GPGPU version would be (very) desirable, but with only one programmer on the project, maintaining separate  non-GPU and GPU versions isn't an option.<br>
  Also, the code will be GPLed, and we'd like to see it being used by others that may have vastly different hardware.</p>
  
  <p>So the entire program has to be easy to compile/run without having a GPU or even a multicore system.<br>
  OpenCl seems like a good option, as it can be run on machines without GPUs, but how will this code perform on a single-core or 32b system?<br>
  Would it be possible to write the code in such a way that it can easily be compiled without openCL?</p>