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Author Topic: CPU Usage Drop  (Read 7167 times)

IanJohnson

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CPU Usage Drop
« on: June 30, 2011, 06:50:05 PM »

Often while generating a mesh on smooth, CPU usage will drop to 1-5%, and the process will never complete (maybe if I left it for days it would).  I thought it was caused by running out of memory, but I've seen it happen near the limit, but not exceeding.  Memory usage still varies, and there is an occasional spike, or one core might run at 20% for a little bit and drop off again.

This always seems to happen at 46% completion.  I dread 46%, and if it makes the jump to 82% I know the mesh will most likely complete.

It is currently doing it on a chunk with 69 10MP photos on a 3 core AMD with 8GB of RAM in Win7.  It's done the same thing on my work computer, with is a MacPro with 8 cores and 8GB RAM.


janosch1234

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Re: CPU Usage Drop
« Reply #1 on: June 30, 2011, 11:23:57 PM »
Hi Ian,

the 46% ->82% jump is normal i guess. I think there are no substeps in this calculationphase that inform the progress dialogue, but dont worry its calculating.

If you are calculating 69 10MP in one chunk in high setting, then you could be probably right that this could last days.
The meshgeneration phase is not multithreaded, so if one one core is at 100% thats normal. I guess that 8 gb could be not sufficient in this case too, but i am not sure about that)

You can always estimate when you do a quick check with a 2 steps lower setting. (a step lower means the image will have a resolution 1/2 in x and 1/2 in y. )
E.g. if you want to calculate with high and estimate the calculationtime, take the low-setting and then multiply the processing time by 16.
(And if you run out of memory the factor will be way much higher of course)

Best regards
Jan


« Last Edit: June 30, 2011, 11:33:34 PM by Jan Wesbuer »

IanJohnson

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Re: CPU Usage Drop
« Reply #2 on: June 30, 2011, 11:46:37 PM »

I'll try with the lower setting, though I am already doing medium.  I haven't been successful doing anything at high with 10MP on 8GB.   I know that mesh generation isn't mulithreaded, and I can see the one core being used on the Mac, but the PC always shows all 3 cores running full.  I don't know if it is a quirk with task manager or what.

I wish there was a good way to predict memory use.  I want the chunks to be as big as possible, and not limit the number of possible photos that might contain a point.  Every time I guess wrong, it's a few hours lost.

janosch1234

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Re: CPU Usage Drop
« Reply #3 on: July 01, 2011, 12:16:09 AM »
you are right, thats probably not a bad suggestion:
Would be nice if PS calculates, based on the number of photos in a chunk (& megapixel) and the settings, the maximum memory usage and warns the user if the physical limit will be possibly reached. (something like a "your calculation will possibly need x gb of ram, your have only y of physical ram available, do you really want to continue" yes/no).

Regards
Jan
btw.: I am right now on 46% after 4,5h and still waiting for the jump to 82%  ;)
« Last Edit: July 01, 2011, 01:10:17 AM by Jan Wesbuer »