CPU Node limitation (on some CPU) #32907

New Issue

mickaël bourgeoisat · 2012-10-17T18:10:05+02:00

2012-10-17 18:10:05 +02:00

%%%Hi !
If we use more than 100 nodes in cycles, they are only exploited under GPU, but not under CPU !
But only on some cpu !!!
On a P7450 and an I7 960 the bug happen, but under a i5 2550K not !!!!

I've spoken with Brecht during the bconf, and he suggested to me to push the info in this bug tracker, so here it is.

This bug have been seen under a 2.63.22 (graphicall/444) a 2.64 and a 2.64a from blender.org
here is the scene : http://octopod-studio.com/divers/physcallycorrectmatexamples001.blend
There is different case on every suzanne in the test scene ... but look at the middle one.
If you put an hdr in the world or not don't change anything.
here it come also two render test images.
Regards.
Myke.

%%%

%%%Hi ! If we use more than 100 nodes in cycles, they are only exploited under GPU, but not under CPU ! But only on some cpu !!! On a P7450 and an I7 960 the bug happen, but under a i5 2550K not !!!! I've spoken with Brecht during the bconf, and he suggested to me to push the info in this bug tracker, so here it is. This bug have been seen under a 2.63.22 (graphicall/444) a 2.64 and a 2.64a from blender.org here is the scene : http://octopod-studio.com/divers/physcallycorrectmatexamples001.blend There is different case on every suzanne in the test scene ... but look at the middle one. If you put an hdr in the world or not don't change anything. here it come also two render test images. Regards. Myke. %%%

mickaël bourgeoisat commented

2012-10-17 18:10:05 +02:00

Changed status to: 'Open'

Thomas Dinges commented

2012-10-18 11:55:16 +02:00

%%%Hi,
I can see the difference between CPU and GPU.

But I don't get why it is different on several CPUs.
Do the different systems have different Operating systems, same build or different Blender builds? Thanks. %%%

%%%Hi, I can see the difference between CPU and GPU. But I don't get why it is different on several CPUs. Do the different systems have different Operating systems, same build or different Blender builds? Thanks. %%%

mickaël bourgeoisat commented

2012-10-20 11:32:55 +02:00

%%%Hi !
I've tested with sames builds on 3 computers, with the official 2.64 , 2.64a and a 2.63.22 (r50896) it's the same results with each build.
I think the problem is comming from two specifications of the CPU.
First : with real cores on a second generation I5 no problem. But on hypertreading first generation , there is some problems.
With older cpu (core2duo) the problem occured systematically ...
Every machine are under seven 64 pro (same version).
So ... Perhaps it's coming from the instruction set on the cpu... Or memory manadgement problem between the system and the cpu...
i think we can't find the real reason without a complete debug/trace of execution (can't make this, i'm not at this level of programming ! )
Perhaps the problem is more deep in blender, because i've got same problems on baking on fx, simulations give not the same results !
Regards ...
Myke
%%%

%%%Hi ! I've tested with sames builds on 3 computers, with the official 2.64 , 2.64a and a 2.63.22 (r50896) it's the same results with each build. I think the problem is comming from two specifications of the CPU. First : with real cores on a second generation I5 no problem. But on hypertreading first generation , there is some problems. With older cpu (core2duo) the problem occured systematically ... Every machine are under seven 64 pro (same version). So ... Perhaps it's coming from the instruction set on the cpu... Or memory manadgement problem between the system and the cpu... i think we can't find the real reason without a complete debug/trace of execution (can't make this, i'm not at this level of programming ! ) Perhaps the problem is more deep in blender, because i've got same problems on baking on fx, simulations give not the same results ! Regards ... Myke %%%

Brecht Van Lommel commented

2012-10-24 11:48:26 +02:00

%%%Just a small note that I can redo the problem, and know what's causing it. It's not a trivial fix so may take a few days before I get time to work on it.%%%

mickaël bourgeoisat commented

2012-10-24 11:50:41 +02:00

%%%Hi brecht !
Thanks a lot for your job !
Regards
Myke%%%

%%%Hi brecht ! Thanks a lot for your job ! Regards Myke%%%

Brecht Van Lommel commented

2012-11-26 22:59:29 +01:00

%%%Sorry this took so long, but fix is in svn now. There's still some hardcoded limits, mainly due to GPU, but it should be able to handle more complex node setups now.%%%

Brecht Van Lommel commented

2012-11-26 22:59:29 +01:00

Changed status from 'Open' to: 'Resolved'

Brecht Van Lommel closed this issue

2012-11-26 22:59:29 +01:00

mickaël bourgeoisat commented

2012-11-28 09:29:47 +01:00

%%%Thanks a lot brecht :) we'll test it asap ...
%%%

%%%Thanks a lot brecht :) we'll test it asap ... %%%

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CPU Node limitation (on some CPU) #32907