Activities

• Continuing the porting-process of the SWRAD modules
• Running benchmarks (of entire WRF simulations) on different resources
• Working on final presentation

   

Problems

• To get some results on different systems, Gabriel was able to run the simulations on his home computer, which has an nVidia 250 gt, and an Intel Core2Duo CPU. This configuration actually got worse performance for both the CPU and GPU versions of the test. This is a very bizarre outcome, considering that his computer is more powerful in every observable regard. The operation system distribution being used was the same as well. Furthermore, the GPU results were around 15% slower than the CPU results. He tried running a gprof analysis, but the execution failed.

   

• Another difficulty that I've found about working with cuda is that, even though blinking on the screen gives an indication that there is a problem with the code that is causing a runtime error, but the location of the runtime error is very vague. For exaple, while using our testing technique in which we only run certain sections of the code, commenting out certain portions causes this ``blink.'' However, this has shown some of the shortcomings of this porting approach that perhaps porting first to C would have helped with. For example, if I have a partial swrad kernel that simply sets one of the output variables to a static variable, the code runs fine. However, if I start modifying other variables, in a subroutine, even if I don't make any changes to the same output variable, the ``blinkage'' occurs and the variable's values are unset. If I set the variable's values to some function of the other variables, the code works fine. This makes the porting process difficult, since we need to modify small sections of code at a time to compare our results to the Fortran results.

   

Plans

• Continue with the porting
• Run tests on Teragrid

   

Some Final Pictures

Picture during my final presentation

Picture of Gabriel and I working at Esteban's Media Lab