Re: [ESPResSo-users] CUDA error: out of memory

[Florian Fahrenberger]

Hi Markus!

>> Can I use more than 1 GPU for a simulation?
> Yes, and that is what you are doing. 

Stefan, you misread. :o) More than one GPU, not more than 1GB...

At the current state, you can not use GPU clusters. It may become a
feature in the future, as more and more people are interested in it.

Cheers,

Florian

You get the error because your GPU memory is full! If you need more than
200^3 you need a GPU with more memory as we cannot do multi-gpu (yet).
> Cheers
> Stefan
> 
>>
>> Markus
>>
>>
>> On 02.08.2013 11:17, Stefan Kesselheim wrote:
>>> Hi Markus,
>>> yes, that is quite right. We need 19xN single precision float numbers per 
>>> LB cell, times two, because we stream from one lattice to a second lattice 
>>> to avoid race conditions.
>>> 200**3 cells *19 populations * 4 byte * 2 buffers=1216MB,
>>> We need a bit more to save forces and so I'd conclude you have a 2GB GPU.
>>> Cheers
>>> Stefan
>>>
>>> On Aug 2, 2013, at 11:01 AM, Markus Gusenbauer <address@hidden> wrote:
>>>
>>>> Hi all,
>>>>
>>>> is the number of nodes with the LBM on GPU limited by hardware? When I 
>>>> choose too large simulation size, I get a CUDA out of memory error.
>>>> Right now I am limited to around 8,320,000 nodes (200x200x208), after that 
>>>> it crashes.
>>>>
>>>> Example:
>>>>
>>>> setmd time_step 0.1
>>>> setmd skin 0.2
>>>> thermostat off
>>>>
>>>> set boxX 200
>>>> set boxY 200
>>>> set boxZ 208
>>>>
>>>> setmd box_l $boxX $boxY $boxZ
>>>>
>>>> lbfluid gpu grid 1 dens 1.0 visc 1.5 tau 0.1 friction 0.5
>>>>
>>>> set cycle 0
>>>> while { $cycle<100 } {
>>>>    puts "$cycle / 100 \r";
>>>>
>>>>    for { set i 1 } { $i < [expr $boxX-1]} { incr i } {
>>>>        for { set j 1 } { $j < [expr $boxY-1] } { incr j } {
>>>>            for { set k 0 } { $k < 1 } { incr k } {
>>>>                lbnode $i $j $k set u 0.0 0.0 0.001
>>>>            }
>>>>        }
>>>>    }
>>>>
>>>>    integrate 1
>>>>    incr cycle
>>>> }
>>>>
>>>>
>>>> Thanks!
>>>>
>>>> Markus
>>>>
> 
> 
>