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

[Azamat Mametjanov]

What happens if you try to re-run with "--with-debugging=no"?

On Fri, Aug 3, 2012 at 10:00 PM, Xiangze Zeng <zengshixiangze at 163.com>wrote:

> 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
>
>
>
>
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