[Bf-cycles] Blender Viewport performance issue after Cycles render (since changing to CUDA Toolkit 5.0)

Thomas Dinges blender at dingto.org
Sun Jun 23 20:05:22 CEST 2013

please report issues to our bug tracker and not to the mailing list, 
much easier to track problems there. :)

Am 23.06.2013 20:00, schrieb David Black:
> On 23/06/2013 18:03, Brecht Van Lommel wrote:
>> I have no idea how this is possible, all the toolkit changes is code
>> that runs on the NVidia graphics card, not how it interacts with other
>> graphics drivers. So perhaps it's another recent change in Cycles or
>> elsewhere in Blender that is causing this?
> Apologies, not Toolkit 5.0 related, after performing your tests below 
> discovered it goes back further.
>> * What is the version number of the build before the toolkit change
>> that still gave good performance (to narrow down the revisions)?
> *blender-2.67-r57293-win64* is okay, Viewport performance same before 
> and after F12 Cycles render.
> *blender-2.67-r57348-mingw64* Is okay except for border render issue, 
> otherwise same as above.
> *blender-2.67-r57476-win64* First versions (I have) that shows the 
> issue, Viewport performance same as previous version until F12 Cycles 
> render, then very slow jerky Viewport performance.
>> * Does this really only happen with GPU rendering, CPU rendering does
>> not show the same issue?
> Interesting test idea. Same issue after either GPU or CPU F12 Cycles 
> render
>> * What is performance like with VBO's switched off before rendering
>> (in case the rendering somehow switches them off)?
> Not as smooth, around 10-15fps but still faster than after rendering, 
> which then feels around 2fps.
>> * What is the performance like with the NVidia card, is it also 2fps
>> or somewhere in between?
> Not yet tested, once wiring configurations are changed will email 
> results. Thought quick reply with above answers would be appreciated.
>> * Is a Blender restart needed or does reopening the scene solve the issue too?
> Interesting, reopening the same scene without restarting Blender also 
> solves the issue, until an F12 Cycles render is performed.
> David
>> Can anyone else confirm this problem?
>> On Sun, Jun 23, 2013 at 5:36 PM, David Black<db4tech at yahoo.co.uk>  wrote:
>>> Hi Brecht,
>>> Just discovered an interesting issue, seems to have been introduced since
>>> Blender changed to CUDA Toolkit 5.0. Not related to Cycles render speeds,
>>> which consequently have received a great boost after code re-factoring.
>>> Issue is connected with Viewport performance after performing a Cycles
>>> render.
>>> Issue outlined below:
>>> Upon opening a complex scene, with a heavy particle system (particles
>>> Viewport setting of 1, Child particles 0), Viewport navigation (VOBs
>>> enabled) with an Intel HD 4000 (part of i7 CPU) is extremely fluid, like
>>> 30fps or more, (much slower on GTX 580 due to double sided Normals
>>> restrictions).
>>> With recent Blender versions, everything is fine until a F12 Cycles render
>>> is performed (does not happen with Viewport render), after which Viewport
>>> navigation becomes extremely sluggish, feels like 2fps. Hiding the heavy
>>> particle object returns full Viewport performance, once object is unhidden
>>> Viewport is back to a crawl. Closing and opening Blender with the same scene
>>> and everything is back to normal, until the next F12 render is performed.
>>> Blender versions prior to Toolkit 5.0 changes, Viewport performance remains
>>> just as fluid after a F12 Cycles render, also tested Blender 2.67b.
>>> Today's BuildBot version (official) blender-2.67-r57660-win64 produces the
>>> sluggish Viewport issue after a F12 Cycles render.
>>> David
>>> --
>>> 3d-designs-davidblack.blogspot.com
>>> _______________________________________________
>>> Bf-cycles mailing list
>>> Bf-cycles at blender.org
>>> http://lists.blender.org/mailman/listinfo/bf-cycles
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Thomas Dinges
Blender Developer, Artist and Musician


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