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HOUDINI NOT USING ALL OF THE RAM


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Hello,

 

I am using Houdini 12.5, and doing some pyro simulations. Earlier the speed was fine. But recently Houdini is using only 2 GB of RAM while I have 16 GB installed.This makes the simulation tremendously slow, even playing on timeline with a division size of 3 takes several minutes to calculate. 

 

I searched for the appropriate reasons, but none of them solved the issue. Can anyone please tell me what must be the issue?? 

 

Thank you.

-Swapniel.M

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As stated above, your sim doesn't need more than the RAM it uses. Check if you didn't accidentally change a crucial parameter that is responsible for your simulation being slow, which can happen easily when working with Pyro. There's also a slight chance some capital letters on your machine might have eaten up the RAM as they are sooo huge. ;)

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@Phlok: Thanks for the reply. :)

 I checked that other sims are pretty fast which are heavier than this one. I don't know which parameter led to the slow simulation. I'll try to find that.

But how can capital letters eat up my RAM. I'm sorry but I didn't get this one.  :unsure:

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having a quick look at your scene your problem is with the division size on your fluid source node.  With such large spheres moving out at that speed will slow down your cook time.  try using smaller spheres as your source, and you can always write out your fluid source node before reading it into dops and it won't slow down your sim.

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Yes indeed my spheres were big. And reducing them have enhanced the speed a bit. Thanks for this one. :)  

But if Houdini is taking so much time to cook, why doesn't it use the available RAM and CPU. Here only 2-3 GB RAM is getting used, and on the other hand, Houdini hangs. I don't get the point of not using the available power and getting hang by itself.  :(

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there seem to be a general misconception I've heard around that 'using all Ram' equates to being faster and better.  It's the opposite in reality - using less Ram is much more efficient. More Ram usage means more data to move between the CPU and Ram sticks, which is slower, and also more Ram usage means more data for the Cpu to process, which is slower.

 

In regards to using more of the Cpu cores, that depends on how the algorithms can be split between the various processes in the CPU. This doesn't happen automatically and has to be programmed to work. e.g. if your algorithm is running across 6 cores the data may have to arrive in completion in the correct order to be useful.  More complex process like simulations require more work to make it multi-threadable. 

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there seem to be a general misconception I've heard around that 'using all Ram' equates to being faster and better.  It's the opposite in reality - using less Ram is much more efficient. More Ram usage means more data to move between the CPU and Ram sticks, which is slower, and also more Ram usage means more data for the Cpu to process, which is slower.

 

In regards to using more of the Cpu cores, that depends on how the algorithms can be split between the various processes in the CPU. This doesn't happen automatically and has to be programmed to work. e.g. if your algorithm is running across 6 cores the data may have to arrive in completion in the correct order to be useful.  More complex process like simulations require more work to make it multi-threadable. 

 

Sir, I have understood your point which was very straight forward. I don't have much knowledge of how background process works when a simulation is in process. Since I'm more into simulations, Can you please share more of your knowledge on how to efficiently use the available CPU,RAM,etc and get the better results in a relatively less time. Because, many times it happens that even to render flipbook of a not much denser simulation(lowres), either the software hangs, or disc space gets low, or some other memory issues. Then it gets impossible to get the desired results. Since I love Houdini, I would like to learn more about this software. 

 

I'm sorry if I sound kiddish, may be because of my little experience.

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Not totally sure there is a fire and forget solution to speeding things up - I would start by running tests. begin with a 10x10x10 volume area with only a few divisions, then test with more or less divisions, etc. An iterative trial and error approach is a solution.

 

Also I would learn more about computer architecture, the way a computer works for shifting and processing data - you will then be able to run it more efficiently - this is critical if you want to be a professional cgi artist. Probably very helpful to check out online computer science courses. Everything slots into place then :)

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Not totally sure there is a fire and forget solution to speeding things up - I would start by running tests. begin with a 10x10x10 volume area with only a few divisions, then test with more or less divisions, etc. An iterative trial and error approach is a solution.

 

Also I would learn more about computer architecture, the way a computer works for shifting and processing data - you will then be able to run it more efficiently - this is critical if you want to be a professional cgi artist. Probably very helpful to check out online computer science courses. Everything slots into place then :)

 

I got it. Thanks Marty.  :)

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As stated above, your sim doesn't need more than the RAM it uses. Check if you didn't accidentally change a crucial parameter that is responsible for your simulation being slow, which can happen easily when working with Pyro. There's also a slight chance some capital letters on your machine might have eaten up the RAM as they are sooo huge. ;)

Liked your post for the last line  :D

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Hello,

I would like to bring into notice(for beginners like me) some points which I came to know after SreckoM, Phlok, Sierra62 and marty replied to me on this thread.

 

Surely my machine was not at fault,neither was the software. It was the emitter and specifically the division size. At this speed, and with my less division size, the voxel count went to 11 millions within 4-5 frames, which is really insane and indirectly forcing my machine to say -"Hey! I'm not going to calculate that. " :P . So emitter need not be high detailed every time. 

 

Thank you all for replying. :)

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