Multiple GPUs in CUDA 3.2 and issues with Cuda 4.0

Question

I am new to multiple GPUs. I have written a code for a single GPU and want to further speed up by use of multiple GPUs. I am working with two GTX 470 with MS VS 2008 and cuda toolkit 4.0

I am facing two problems.

First problem is my code somehow doesn't run fine with 4.0 build rules and works fine for 3.2 build rules. Also the SDK example of multiGPU doesn't build on VS2008 giving error

error C3861: 'cudaDeviceReset': identifier not found

My second problem is, if I have to work with 3.2 then according to the documentation, threads have to be launched separately and separate allocations to be made etc. What is the easiest library for launching threads for multiple gpus and can you please give some example for my setup for access to multiple GPUs.

Answer 1

The answer to the first question is that you are clearly linking an older version of the CUDA runtime library. cudaDeviceReset is a new addition to the API introduced in CUDA 4.0. So double check the build rules and make sure you really are pointing the linker at the CUDA 4.0 toolkit and not an earlier version

The second part of your question sounds like a "hai plz give me teh code" question, and that isn't really what this place is for. I will, however, give you a link to GPUWorker (code currently available here), which is a boost threads based multigpu framework that was originally part of the HOOMD molecular dynamics package. It should give you some hints on how to do a multithreaded, multigpu code, even if GPUWorker turns out to not be directly applicable to your needs.