[vtkusers] Llvmpipe threads collapses the system when capturing a screenshot

[Patricio Palma C.]

Thanks David.!

I’ve continued debugging and I’ve noticed my VTK code works fine with Mesa
10.6.5 gallium 0.4 on llvmpipe (llvm 3.6)

Could it be a bug in Mesa 17.0.6 gallium 0.4 on llvmpipe (llvm 4.0) the
cause of this issue?

At this moment downgrade is not an option as I also need AVX support which
is available only from Mesa 11.1.

Should I try the latest Mesa version or is there a favorited Mesa version
to use with VTK ?

Regards
Patricio


El El jue, 22 de feb. de 2018 a las 21:03, David Gobbi <
david.gobbi at gmail.com> escribió:

> Hi Patricio,
>
> The primary thing that vtkWindowToImageFilter does is call glReadPixels()
> via vtkOpenGLRenderWindow::GetPixelData().  So you can try
> debugging/profiling the vtkOpenGLRenderWindow.cxx code at the point where
> it calls glReadPixels() to see if that is where the llvmpipe threads are
> being created.
>
>  - David
>
>
> On Thu, Feb 22, 2018 at 4:07 PM, Patricio Palma C. <patriciop at gmail.com>
> wrote:
>
>> Hi All
>>
>>    I’m using vtkWindowToImageFilter to export screenshots of a
>> vtkXOpenGLRenderWindow. It works, but every time a screenshot is created,
>> 15 new llvmpipe threads are spawned and they are not finalized by the app.
>> I noticed this because after a while the number of threads reached the
>> limit (about 5500) and no more threads can be spawned.
>>
>> This application is running linux RH 6.6 / VTK 7.1 / mesa 17.0.6
>>
>>
>>
>> Source code extract:
>>
>>
>>
>> vtkSmartPointer<vtkRenderer> osRenderer =
>> vtkSmartPointer<vtkRenderer>::New();
>>
>> vtkSmartPointer<vtkXOpenGLRenderWindow> renWin =
>> vtkSmartPointer<vtkXOpenGLRenderWindow>::New();
>>
>>
>>
>> renWin->SetOffScreenRendering(true);
>>
>> renWin->AddRenderer(osRenderer);
>>
>> renWin->SetSize(pictureSize.width(), pictureSize.height());
>>
>>
>>
>> // copyActors from QVTKWidget2
>>
>>
>>
>> vtkSmartPointer<vtkWindowToImageFilter> filter =
>> vtkSmartPointer<vtkWindowToImageFilter>::New();
>>
>> filter->SetInput(renWin);
>>
>> filter->SetInputBufferTypeToRGB();
>>
>> filter->SetMagnification(1);
>>
>> filter->Update();
>>
>>
>>
>> vtkSmartPointer<vtkImageData> image = filter->GetOutput();
>>
>> …
>>
>> (continue using image)
>>
>> At this moment I’m using an empty RenderWindow, I thought actors could
>> have a problem so I commented that out but the problem persists.
>>
>> After some testing I’ve noticed that the problem arise after calling
>> filter->Update(). If this line is commented, no picture is generated but
>> the threads are finalized.
>>
>> Any ideas on how can I track this issue or where should I continue
>> looking for an issue in my code?
>>
>>
>> Regards
>>
>> Patricio
>> --
>> Patricio Palma C.
>>
>
> --
Patricio Palma C.
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