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Author Topic: Hardware/Processing optimization  (Read 6335 times)

mwittnebel

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Hardware/Processing optimization
« on: July 25, 2014, 11:10:46 AM »
Hello everybody,

I have some questions to optimizing our hardware configuration for the next processing machine.
First of all i post all of my hardware and Software components:

Hardware
CPU: i7 3930K with 4.2GHz (42x100)
RAM: 32GB (4x8GB DDR3 1600 Kingston CL11) (max load normally between 20-30GB)
GPU: 2x R9 R290
Storage: 1SSD & 1HDD


Software
OS: Win 7 Ultimate (updated)
PhotoScan Pro: 1.0.4 build 1847 (64bit) - 0/12 CPU (Dense Cloud)
Catalyst Version 14.4
Driver Packaging Version: 14.10.1006-140417a-171099C



Now my questions.
Is it possible to increase the load for the GPUs in the "Dense Cloud reconstruction" step ?
In this step is the CPU load on 50-70% and the load for the GPU is very irregular 0-100%.

Also on some steps the CPU load is very disappointing(under 80%) especially if ram usage is increasing or decreasing. I will add a load graph of my system in the future to visualize my request.
Is there a bottleneck in my hardware setup or is this a software related problem ?
I would like to get the optimal load on my system to get the most out of this hardware.( time is money ;) )

Tanks for your attention and i hope we have a good discussion on this topic.
« Last Edit: July 25, 2014, 12:30:46 PM by mwittnebel »

Marcel

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Re: Hardware/Processing optimization
« Reply #1 on: July 26, 2014, 11:54:47 PM »
Not all parts of the process are multi-threaded. If the CPU is not fully utilized it could be because it's running a calculation that just uses one thread/core.

As long as you are not running out of memory there aren't really any bottlenecks. Photoscan just needs a long time on large projects.

David Cockey

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Re: Hardware/Processing optimization
« Reply #2 on: July 27, 2014, 01:24:42 AM »
My understanding is PhotoScan observes the actual performance of the CPU and GPU, and then adjusts the load on each to optimize overall speed.

Lambo

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Re: Hardware/Processing optimization
« Reply #3 on: July 28, 2014, 07:41:57 AM »
Yes, Marcel and David are right and also dont forget to disable 1 CPU core per graphics card in the Photoscan settings, so for your system you should disable 2 Cores.
That way Photoscan will access as much as it can of the GPU's that are MUCH faster than your CPU's.
Also not all the parts of the process use the CPU at its fullest
If I am not mistaken (anyone correct me if I am wrong please) the Aligning part uses mostly the CPU, the Dense Cloud generation uses mostly the GPU and the Mesh generation uses mostly the CPU again.
Leo

David Cockey

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Re: Hardware/Processing optimization
« Reply #4 on: July 28, 2014, 10:54:03 PM »
Align Photos does not use GPU.
Create Dense Cloud uses both CPU and GPU.
Build Mesh does not use GPU.

"Disabling" CPU cores does not actually disable specific cores. All cores continue to be used. I experimented with "disabling" various numbers of cores and did not find major differences in execution time. The AgiSoft advice of "disabling" 1 physical core per GPU appeared to be best. For a i7 4 core / 8 hyperthread CPU that means disabling 2 of 8 "cores".


an198317

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Re: Hardware/Processing optimization
« Reply #5 on: July 29, 2014, 12:40:24 AM »
I did multiple test and found the same thing David found. I was thinking why Generating Mesh can't use GPU, which is the slowest part of the processing.

Wishgranter

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Re: Hardware/Processing optimization
« Reply #6 on: July 29, 2014, 11:33:47 AM »
Because Meshing part need load complete model in  RAM - multiple GBs. So  if we have say 32-64 GB on  GPUs then it can be done on GPU..... its not a easy  to solve problem..... 
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