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Author Topic: Slow alignment time - compare between computers  (Read 3356 times)

kgrover

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Slow alignment time - compare between computers
« on: September 14, 2016, 06:16:10 PM »
I have an issue with our main processing workstation right now, with much slower performance of it to a laptop of mine, but only for certain processes in Agisoft. The attached image outlines the two areas, with the Alignment time being much slower on my desktop than my laptop.

The desktop is a dual Xeon E5-2650 V2 with a Quadro K5200 and 128GB of RAM, whereas my laptop has in I7-3740QM with a Quadro K4000M with 32GB of RAM. Both running Windows 7 Enterprise.

Every other process is much faster on my desktop, except for the Alignment Time. The matching time is faster, but not the alignment.

I am not sure why this would be so much different, and I have also played with all the OpenCL settings as well.

Any ideas would be appreciated.

Kevin

aloerch

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Re: Slow alignment time - compare between computers
« Reply #1 on: September 21, 2016, 02:15:49 AM »
Hi,

I'm going to go out on a limb here and suggest that what you are experiencing is probably a difference in clockspeed of the desktop CPU versus laptop CPU. Here's a bit of background:

1. Photoscan does not use the GPU's for the alignment process, that is 100% CPU based.
2. You do not specify the number of cores or clockspeeds of either the laptop or desktop, but because the alignment process is 100% CPU based, this could be the reason for the difference.

Also, it could just be that your anti-virus was running on the desktop and not the laptop during processing... or updates were being downloaded/installed, or the moon was passing through the 8th house of Jupiter (lol)?

O_and_N

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Re: Slow alignment time - compare between computers
« Reply #2 on: September 21, 2016, 11:45:19 AM »
Im new to this but will try.
You have 2x8 core cpus at base clock of 2.6ghz and a 4 core laptop cpu at 2.7ghz.

Two things of my mind.
On how many ram sticks are the 128gb separated?
Find some free soft that displays cpu speed on your screen and do a alignment again.This time observe if the cores of the 2 xeons go in to turbo booost mode surpasing the 2.6ghz base clock and going up towards 3.0-3.4ghz on all cores.

Try this first.

kgrover

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Re: Slow alignment time - compare between computers
« Reply #3 on: September 21, 2016, 04:56:59 PM »
Thanks for the comments guys, but I have done a number of checks on my desktop and all things seem to spec out fine on it. I ran a benchmarking program I found, and the dual CPU benchmarks over twice the rating of my laptop, so it seems to be fine as well. I also had my IT guys swap out my old RAM (64GB), but it operates the same as my 128GB.

I was wondering about Anti-Virus, etc., but it is weird to me that the Alignment step is the only process that is slower than my laptop, and just the one step of the Alignment Time. In looking at the CPU usage during this step it is running 100 percent of all cores as well.

Just to check, I also just reran an old project from a year ago that was done on the same desktop, and I am now seeing that same much slower alignment time as well. See the attached screenshot. The matching time is virtually identical, but the old "Alignment Time" was 3 minutes and 7 seconds, while the new was 26 minutes 21 seconds.

I am not sure if I just have some incompatibility on my desktop right now, but still see it as odd that it is only that one step that it is having a serious issue with.

Kevin

Alexey Pasumansky

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Re: Slow alignment time - compare between computers
« Reply #4 on: September 21, 2016, 05:13:40 PM »
Hello Kevin,

Can you please provide the log files related to the Align Photos operation for both computers? Please also inform us if all the CPU cores are shown as 100% utilized in the Task Monitor, and whether hyper-threading is enabled.
Best regards,
Alexey Pasumansky,
Agisoft LLC

kgrover

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Re: Slow alignment time - compare between computers
« Reply #5 on: September 21, 2016, 07:22:41 PM »
Hi Alexey,

I have attached the log files for both my desktop and laptop, and there was a big difference between the two.

Desktop - 10min, 46 seconds Matching Time, 43 minutes, 6 seconds alignment time
Laptop - 17min, 22 seconds matching time, 14 minutes, 28 seconds alignment time

Same processing parameters of 136 images, high accuracy with reference preselection, key point limit 40,000 and tie point limit of 15,000.

Yes, hyperthreading is enabled on both machines and utilizing all cores/threads to 100 percent.

Kevin

kgrover

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Re: Slow alignment time - compare between computers
« Reply #6 on: October 04, 2016, 09:25:27 PM »
Hi Alexey, any update or feedback on this??

I am still having the same issues with this dataset and others.

Kevin