CS 385 Lab 11, Spring 2009

[Back to CS 385 schedule]

This is the last programming lab. Subsequent "labs" are based only on reading material and will be due at 1:00 PM on Monday 5/4, Wednesday 5/6, and Monday 5/11.

In this lab, you will modify your code from Lab 10 to optimize the reduction operation.

Infrastructure

You should log into your cwolf account and then ssh to rickroll from cwolf. All your cwolf files are visible on rickroll. You may also do this assignment at home if you have a CUDA-capable graphics card; if you do, mention in your initial comment that you worked at home and note the model of your graphics card (e.g. NVidia GeForce 9800 GT).

To compile programs, type nvcc -o outputfile sourcefile.cu
If you run into problems other than syntax errors, the likely culprit is your environment variables. You may need to source your ~/.bash_profile again.

Directions

Your file should be called yourlastnameL11.cu and should contain the following:

Your source code from Lab 10
At least one of the optimizations described in this document, or another optimization of your choice. You may overwrite your Lab 10 code as necessary.

Timing

In your initial comment, include the following time measurements (and list the value of N you used for them):

3 time measurements for the sequential code and their average. You can copy this from Lab 10.
3 time measurements and their average for each of at 2 different CUDA configurations (different block dimensions/grid dimensions), using the sequential reduction. You can copy this from Lab 10.
3 time measurements and their average for each of at 2 different CUDA configurations (different block dimensions/grid dimensions), using the parallel reduction from Lab 10.
3 time measurements and their average for each of at 2 different CUDA configurations (different block dimensions/grid dimensions), using your newly optimized parallel reduction.

In addition, include an explanation of your optimization and the performance results you saw.

Submitting your file

Make sure that your file is correctly named and then copy it to ~srivoire/cs385/submit. Wait 2 minutes, and then check that it was correctly submitted by visiting http://rivoire.cs.sonoma.edu/cs385/lab11sub.txt.