[petsc-users] Why does GPU solve the large sparse matrix equations only a little faster than CPU?

[Xiangze Zeng]

Dear Matt,


My CPU is Intel Xeon E5-2609, GPU is Nvidia GF100 [Quadro 4000]. 
The size of the system is 2522469 x 2522469, and the number non-0 elements is 71773925, about 0.000012 of the total. 
The output of -log_summary is in the attachment. The G_log_summary is the output when using GPU, C_log_summary when using CPU. 


Zeng Xiangze


在 2012-08-03 22:28:07，"Matthew Knepley" <knepley at gmail.com> 写道：
On Fri, Aug 3, 2012 at 9:18 AM, Xiangze Zeng <zengshixiangze at 163.com> wrote:

Dear all,


When I use the CPU solve the equations, it takes 78 minutes, when I change to use GPU, it uses 64 minutes, only 15 minutes faster. I see some paper say when using PETCs with GPU to solve the large sparse matrix equations, it can be several times faster? What's the matter?


For all performance questions, we at least need the output of -log_summary. However, we would also need to know


  - The size and sparsity of your system


  - The CPU and GPU you used (saying anything without knowing this is impossible)


   Matt
 
Thank you!


Sincerely,
Zeng Xiangze








--
What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.
-- Norbert Wiener
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20120804/893a5743/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: C_log_summary
Type: application/octet-stream
Size: 10079 bytes
Desc: not available
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20120804/893a5743/attachment.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: G_log_summary
Type: application/octet-stream
Size: 10430 bytes
Desc: not available
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20120804/893a5743/attachment-0001.obj>