Question about compiling and 100% cpu usage

Im kinda noob at this GPGPU (for now :) ) and have few questions:

  1. when i run fluidsGL compiled as release i get (on the top of the window) 512x512 and when compiled as emurelease only 64x64 (as i understand code is the same, but why is in emurelease case only 64x64?))

  2. why is cpu at 100% when running fluidsGL as release (as i understand it should be computing on graphics card, is this the cause of printing image on screen, or something related to the bandwidth?)?

  3. why i get at example “alignedTypes” all TEST FAILED, while in emurelease mode i get TEST PASSED?

  4. why i get segmentation failed at some examples running compiled as release (it works fine if i run executable which was compiled as emurelease)?

  5. how exactly ‘make’ with emurelease compile programs, it simulate all gf8 functions or … (why is soo much slower)?

Thanks for reply.

PS: I appologize if questions seems stupid :">

As you pointed out later in this post, emurelease is very slow. Would you really want it to run 512x512? :)

When the CPU is waiting for the GPU to finish computing or to finish a DMA operation, it uses 100% of the CPU. This will reportedly be fixed in a future release, though NVIDIA has not indicated exactly when.

emurelease runs on the CPU instead of the GPU. So it is possible to see differences. But I haven’t run into these problems you mentioned. Maybe you can give details of your hardware/software environment.

Yes, it simulates the GPU threads on the CPU. In fact, you can see hundreds of threads being launched on the CPU when a kernel is executed.

Thanks for fast reply.

Well my graphic card is low-end performance, soo it this might be the case.
Geforce 8400 gs 256mb
AMD 64 x2
2gb ram
runing on 64-bit ubuntu gusty gibbon

Ubuntu was never qualified for use with CUDA-1.0. Ubuntu will be qualified for the next CUDA release.