Programming Parallel Computers

Aalto 2024

CP4: GPU baseline ★

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What you will need to do in this task

Please read the general instructions for this exercise first. Here are the additional instructions specific to this task:

Implement a simple baseline solution for the GPU. Make sure it works correctly and that it is reasonably efficient. Make sure that all performance-critical parts are executed on the GPU; you can do some lightweight preprocessing and postprocessing also on the CPU. Remember to check all CUDA operations for errors. In this task, you are permitted to use single-precision floating point numbers.

What I will try to do with your code

I will first run all kinds of tests to see that your code works correctly. You can try it out locally by running ./grading test, but please note that your code has to compile and work correctly not only on your own computer but also on our machines.

If all is fine, I will run the benchmarks. You can try it out on your own computer by running ./grading benchmark, but of course the precise running time on your own computer might be different from the performance on our grading hardware.

Benchmarks

Name Parameters
benchmarks/1a nx = 1000, ny = 1000
the input contains 1000 × 1000 pixels, and the output should contain 1000 × 1000 pixels
benchmarks/1b nx = 999, ny = 999
the input contains 999 × 999 pixels, and the output should contain 999 × 999 pixels
benchmarks/1c nx = 1001, ny = 1001
the input contains 1001 × 1001 pixels, and the output should contain 1001 × 1001 pixels
benchmarks/2a nx = 1000, ny = 4000
the input contains 4000 × 1000 pixels, and the output should contain 4000 × 4000 pixels
benchmarks/2b nx = 1000, ny = 4000
the input contains 4000 × 1000 pixels, and the output should contain 4000 × 4000 pixels

Grading

In this task your submission will be graded using benchmarks/2b: the input contains 4000 × 1000 pixels, and the output should contain 4000 × 4000 pixels.

The point thresholds are as follows. If you submit your solution no later than on Sunday, 19 May 2024, at 23:59:59 (Helsinki), your score will be:

Running timePoints
≤ 5.000 sec 1
≤ 3.000 sec 2
≤ 2.000 sec 3
≤ 1.000 sec 4
≤ 0.500 sec 5

If you submit your solution after the deadline, but before the course ends on Sunday, 02 June 2024, at 23:59:59 (Helsinki), your score will be:

Running timePoints
≤ 3.000 sec 1
≤ 2.000 sec 2
≤ 0.500 sec 3