QOpenglWidget memory leak
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"Just like the program I provided, using Qt 5.15.2, Visual Studio 2019 (2022), a 4K display, and Intel integrated graphics, after compiling and running, when you hover the mouse back and forth between the top two buttons, continuously and rapidly repeating this action, you can observe that the program's memory usage keeps increasing until it crashes."
code is here https://github.com/huxingqun/problems/tree/main/Qt/TestOpenGLWidget
@xingqun Not sure what you expect? That somebody analyses your code and tells you what the problem is? Did you do any analysis on your own already? There are tools to search for memory leaks.
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@xingqun Not sure what you expect? That somebody analyses your code and tells you what the problem is? Did you do any analysis on your own already? There are tools to search for memory leaks.
wrote on 19 Feb 2024, 14:48 last edited by@jsulm The code logic should be fine. I encountered this memory leak issue in another project, so I wrote this demo to validate it further. I found that there is also a memory leak in this demo. Currently, I've used Visual Studio's memory tool to analyze it, but haven't identified the problem. Therefore, I'd like to seek help on this matter.
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@jsulm The code logic should be fine. I encountered this memory leak issue in another project, so I wrote this demo to validate it further. I found that there is also a memory leak in this demo. Currently, I've used Visual Studio's memory tool to analyze it, but haven't identified the problem. Therefore, I'd like to seek help on this matter.
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@xingqun your qt code is simple. It is likely openGL related leak. Test your code on Linux with valgrind and you may be able to find something
Especially in void NVOpenGLWidget::paintGL()
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@JoeCFD Have you encountered any memory issues when mixing QOpenGLWidget and QWidget? I've noticed memory leaks even when using the official Qt demo.
@xingqun said in QOpenglWidget memory leak:
I've noticed memory leaks even when using the official Qt demo.
Please provide a minimal, compilable example to reproduce this leak.
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"Just like the program I provided, using Qt 5.15.2, Visual Studio 2019 (2022), a 4K display, and Intel integrated graphics, after compiling and running, when you hover the mouse back and forth between the top two buttons, continuously and rapidly repeating this action, you can observe that the program's memory usage keeps increasing until it crashes."
code is here https://github.com/huxingqun/problems/tree/main/Qt/TestOpenGLWidget
wrote on 24 Feb 2024, 08:02 last edited by@xingqun HI I recommened you to use gdb. Becauase it helps to get where exactly crash happens. In one of the my project i have found the crash using it.
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@xingqun said in QOpenglWidget memory leak:
I've noticed memory leaks even when using the official Qt demo.
Please provide a minimal, compilable example to reproduce this leak.
wrote on 25 Feb 2024, 04:06 last edited by@Christian-Ehrlicher You can compile and run this project. I'm using Qt 5.15.2 + VS2019. Then, compile and run it in Qt Creator. After running, maximize the software, then continuously drag the graphic back and forth with the mouse to keep it refreshing constantly. This way, you can observe the memory continuously increasing in the Task Manager.
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wrote on 25 Feb 2024, 06:27 last edited by
Not sure if the memory leak reported here was on the CPU side or GPU side but at least regarding GPU memory there are definitely bugs in the implementation and I've seen issues on X11, NV, Qt5.
This is what I found at the time.
https://forum.qt.io/topic/92179/xorg-vram-leak-because-of-qt-opengl-application/12
https://community.khronos.org/t/xorg-vram-leak-because-of-qt-opengl-application/76910/2
https://bugreports.qt.io/browse/QTBUG-69429 -
Not sure if the memory leak reported here was on the CPU side or GPU side but at least regarding GPU memory there are definitely bugs in the implementation and I've seen issues on X11, NV, Qt5.
This is what I found at the time.
https://forum.qt.io/topic/92179/xorg-vram-leak-because-of-qt-opengl-application/12
https://community.khronos.org/t/xorg-vram-leak-because-of-qt-opengl-application/76910/2
https://bugreports.qt.io/browse/QTBUG-69429wrote on 25 Feb 2024, 13:49 last edited by@SamiV123
Here are a few observations we made during debugging from our end:The higher the screen resolution, the faster the memory leak occurs. This was the direct cause we identified for the issue. When our client's computer with a 4K resolution runs our application, it experiences a memory leak leading to a crash. Therefore, we reproduced the problem using a 4K resolution. Both our custom demo and the official Qt demo consistently exhibit this behavior.
We used Visual Studio's memory snapshot for analysis but didn't find any leaked stack traces.
On machines with NVIDIA dedicated graphics cards, setting the software mode to high performance, thereby ensuring it primarily uses the dedicated GPU for OpenGL rendering, prevents memory leaks.
On machines with Intel integrated graphics, memory accumulation and leaks occur.
I suspect this could be due to the integrated graphics struggling to handle the data, resulting in memory accumulation. However, this is just my speculation. Currently, this issue is quite challenging, and we haven't found a solution yet. -
@SamiV123
Here are a few observations we made during debugging from our end:The higher the screen resolution, the faster the memory leak occurs. This was the direct cause we identified for the issue. When our client's computer with a 4K resolution runs our application, it experiences a memory leak leading to a crash. Therefore, we reproduced the problem using a 4K resolution. Both our custom demo and the official Qt demo consistently exhibit this behavior.
We used Visual Studio's memory snapshot for analysis but didn't find any leaked stack traces.
On machines with NVIDIA dedicated graphics cards, setting the software mode to high performance, thereby ensuring it primarily uses the dedicated GPU for OpenGL rendering, prevents memory leaks.
On machines with Intel integrated graphics, memory accumulation and leaks occur.
I suspect this could be due to the integrated graphics struggling to handle the data, resulting in memory accumulation. However, this is just my speculation. Currently, this issue is quite challenging, and we haven't found a solution yet. -
@SamiV123
Here are a few observations we made during debugging from our end:The higher the screen resolution, the faster the memory leak occurs. This was the direct cause we identified for the issue. When our client's computer with a 4K resolution runs our application, it experiences a memory leak leading to a crash. Therefore, we reproduced the problem using a 4K resolution. Both our custom demo and the official Qt demo consistently exhibit this behavior.
We used Visual Studio's memory snapshot for analysis but didn't find any leaked stack traces.
On machines with NVIDIA dedicated graphics cards, setting the software mode to high performance, thereby ensuring it primarily uses the dedicated GPU for OpenGL rendering, prevents memory leaks.
On machines with Intel integrated graphics, memory accumulation and leaks occur.
I suspect this could be due to the integrated graphics struggling to handle the data, resulting in memory accumulation. However, this is just my speculation. Currently, this issue is quite challenging, and we haven't found a solution yet.wrote on 26 Feb 2024, 20:07 last edited by JoeCFD@xingqun I did quick test with valgrind
==================5.15.2 on Ubuntu 22.04
==556545== LEAK SUMMARY:
==556545== definitely lost: 256 bytes in 1 blocks
==556545== indirectly lost: 32 bytes in 1 blocks
==556545== possibly lost: 0 bytes in 0 blocks
==556545== still reachable: 613,875 bytes in 10,922 blocks
==556545== suppressed: 0 bytes in 0 blocks
==556545== Reachable blocks (those to which a pointer was found) are not shown.
==556545== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==556545==
==556545== For lists of detected and suppressed errors, rerun with: -s
==556545== ERROR SUMMARY: 3 errors from 3 contexts (suppressed: 0 from 0)==================6.6.2 on Ubuntu 22.04
==557606== HEAP SUMMARY:
==557606== in use at exit: 346,588 bytes in 3,812 blocks
==557606== total heap usage: 232,769 allocs, 228,957 frees, 1,005,388,571 bytes allocated
==557606==
==557606== LEAK SUMMARY:
==557606== definitely lost: 0 bytes in 0 blocks
==557606== indirectly lost: 0 bytes in 0 blocks
==557606== possibly lost: 0 bytes in 0 blocks
==557606== still reachable: 344,572 bytes in 3,791 blocks
==557606== suppressed: 0 bytes in 0 blocks
==557606== Reachable blocks (those to which a pointer was found) are not shown.
==557606== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==557606==
==557606== For lists of detected and suppressed errors, rerun with: -s
==557606== ERROR SUMMARY: 6 errors from 4 contexts (suppressed: 0 from 0)You may try a higher version of Qt5 or switch to Qt6.
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