Hi Mani, you're absolutely right, I must have had tomatoes on my eyes... :-/
Thanks and best regards, Karli On 02/23/2014 05:48 PM, Mani Chandra wrote:
I forgot to mention that it is indeed the code I sent in January, but I also attached it in the first email in this thread. Cheers, Mani On Feb 23, 2014 10:42 AM, "Mani Chandra" <[email protected] <mailto:[email protected]>> wrote: Hi Karl, I have attached the code already in my last email. It is the last attachment. The memory leak has been fixed. Thanks! Cheers, Mani On Feb 23, 2014 5:57 AM, "Karl Rupp" <[email protected] <mailto:[email protected]>> wrote: Hi Mani, thanks for the quick feedback. > I tested the updated implementation of the viennacl bindings in petsc-dev/next and I get rather poor performance when using viennacl on either cpu or gpu. I am using the TS module (type:theta) with a simple advection equation in 2D with resolution 256x256 and 8 variables. Good, this has about 500k unknowns, so OpenCL kernel launch overhead should not be a show-stopper. I tested with the following cases: 1) Single cpu with petsc's old aij mat and vec implementation 2) Viennacl mat and vec and using VecViennaCLGetArrayRead/Write in the residual evaluation function on an intel cpu with intel's opencl. 3) Viennacl mat and vec and using VecViennaCLGetArrayRead/Write in the residual evaluation function on an nvidia gpu. The first case is the fastest and the other cases are 2-3 times slower. Attached are the log summaries for each cases and the code I used to test with. I am running using the following command: time ./petsc_opencl -ts_monitor -snes_monitor -ts_dt 0.01 -ts_max_steps 10 -ts_type theta -log_summary As Matt already noted, the bottleneck here is the frequent copy from/to the device. I see 90% of the time spent in MatFDColorApply, so this is where we need to look at. Is there any chance you can send me the code to reproduce this directly? Is it the same you sent me back in January? Btw: Mani, does the memory still get filled up on the GPU for larger time steps? Best regards, Karli
