[Interest] Qt3D memory leaks
william.crocker at analog.com
william.crocker at analog.com
Thu Apr 13 23:57:08 CEST 2017
On 04/13/2017 02:43 PM, Igor Mironchik wrote:
>
>
> 13.04.2017 20:36, Sean Harmer пишет:
>>
>>
>> On 13/04/2017 16:31, Igor Mironchik wrote:
>>> Hi,
>>>
>>>
>>> 13.04.2017 17:55, Igor Mironchik пишет:
>>>>
>>>> Am I right that QEntity doesn't delete its children on destruction and
>>>> just removes them from scene?
>>>
>>> I asked this in context of QEntity::addComponent()...
>>>
>>> Seems that entity doesn't delete anything. And documentation is unclear
>>> in it:
>>>
>>> voidQEntity::addComponent(QComponent <qt3dcore-qcomponent.html>*comp)
>>>
>>> Adds a new reference to the component comp.
>>>
>>> Note: If the Qt3DCore::QComponent <qt3dcore-qcomponent.html> has no
>>> parent, the Qt3DCore::QEntity <qt3dcore-qentity.html> will set itself as
>>> its parent thereby taking ownership of the component.
>>>
>>>
>>> As I can guess it doesn't take ownership. Because of it I have few leaks
>>> at exit but not in restart of tree...
>>
>> The entity takes ownership of any components that are parentless when added.
>> This is done using the usual QObject ownership mechanism so the components
>> will be deleted by the entity when it is being destroyed just like any other
>> QObject parent. There may be a leaks elsewhere but I don't think this is it.
>> There were some leaks related to VAOs fixed around the time of the 5.8.0
>> release. I can't recall if they made it into 5.8.0 or not off the top of my
>> head. Please try with a build from the 5.9 branch in git.
>
> Yes, you are right. QEntity really deletes all children. I checked it.
>
> Then I have no idea what it can be. Every restart of the 5 years tree loses ~30
> - 40 MB of memory.
>
You could use a "memory-in-use" analysis tool.
Contact UNICOM. Get an evaluation copy of Purify(Plus). :-)
1 - Call purify_clear_inuse().
2 - Do your thing.
3 - Call purify_new_inuse().
4 - Study the report and see who allocated memory.
Bill
>
>>
>> Cheers,
>>
>> Sean
>>
>>>
>>>>
>>>>>
>>>>> Are those numbers for Linux or Windows?
>>>>>
>>>>>>
>>>>>>
>>>>>> 13.04.2017 15:39, william.crocker at analog.com пишет:
>>>>>>> On 04/13/2017 08:34 AM, Igor Mironchik wrote:
>>>>>>>> Hi,
>>>>>>>>
>>>>>>>> Strange, I launch 3Dtree on Linux under valgrind:
>>>>>>>>
>>>>>>>> ==4321== HEAP SUMMARY:
>>>>>>>> ==4321== in use at exit: 439,965 bytes in 6,185 blocks
>>>>>>>> ==4321== total heap usage: 2,207,719 allocs, 2,201,534 frees,
>>>>>>>> 1,241,469,509
>>>>>>>> bytes allocated
>>>>>>>> ==4321==
>>>>>>>> ==4321== LEAK SUMMARY:
>>>>>>>> ==4321== definitely lost: 1,080 bytes in 10 blocks
>>>>>>>> ==4321== indirectly lost: 7,609 bytes in 55 blocks
>>>>>>>> ==4321== possibly lost: 416 bytes in 1 blocks
>>>>>>>> ==4321== still reachable: 430,860 bytes in 6,119 blocks
>>>>>>>> ==4321== suppressed: 0 bytes in 0 blocks
>>>>>>>>
>>>>>>>
>>>>>>> Check the virtual image size on Linux,
>>>>>>> just to make sure it is not growing as well.
>>>>>>> That is the bottom line.
>>>>>>>
>>>>>>>> But on my Windows OS after each restart of tree I receive plus
>>>>>>>> ~100MB additional
>>>>>>>> memory.
>>>>>>>>
>>>>>>>> As I can see this memory still reachable. But why 3Dtree allocates
>>>>>>>> more and more
>>>>>>>> memory and doesn't use freed one?
>>>>>>>>
>>>>>>>> 13.04.2017 9:58, Sean Harmer пишет:
>>>>>>>>> Hi,
>>>>>>>>>
>>>>>>>>> On 13/04/2017 07:09, Igor Mironchik wrote:
>>>>>>>>>> Hello,
>>>>>>>>>>
>>>>>>>>>> 3Dtree has been updated. Now autumn is animated. Removed hand-made
>>>>>>>>>> classes of leaf geometry and mesh. Now example uses ready mesh
>>>>>>>>>> prepared
>>>>>>>>>> in Blender. Modified a little constants of the tree. Example
>>>>>>>>>> looks nice.
>>>>>>>>>> This is a benchmark of your video card, because leafs and
>>>>>>>>>> branches are
>>>>>>>>>> stand alone objects (QEntity). For example 5 years tree has ~ 900
>>>>>>>>>> objects. My Intel Pentium with Intel HD graphics normally paint
>>>>>>>>>> only 5
>>>>>>>>>> years tree, 6 years tree starts to slow down.
>>>>>>>>>
>>>>>>>>> Yes, at present each entity with a material/geometry renderer
>>>>>>>>> combo gets
>>>>>>>>> translated to an OpenGL draw call. We are looking to add batching
>>>>>>>>> (similar to
>>>>>>>>> how Qt Quick 2 works) but it's not there yet.
>>>>>>>>>
>>>>>>>>> If you don't need to address each individual leaf/branch in your
>>>>>>>>> object model.
>>>>>>>>> E.g. if you're just rendering them, then you can get *much*
>>>>>>>>> better performance
>>>>>>>>> by using instanced rendering.
>>>>>>>>>
>>>>>>>>> Essentially you have one entity representing all leaves. This
>>>>>>>>> entity contains
>>>>>>>>> the material and geometry renderer as normal. The positions and
>>>>>>>>> any other
>>>>>>>>> custom properties that vary between instances (rotation, leaf
>>>>>>>>> size, leaf
>>>>>>>>> colour etc) should be placed into an additional attribute/buffer
>>>>>>>>> and provided
>>>>>>>>> to the geometry renderer. On this attribute, set the divisor
>>>>>>>>> property to 1
>>>>>>>>> meaning that 1 piece of data maps to 1 instance of the leave in
>>>>>>>>> the scene.
>>>>>>>>> With this approach you will be able to render 10,000's leaves in
>>>>>>>>> a single draw
>>>>>>>>> call. It maps through to a call to glDrawElementsInstanced() in
>>>>>>>>> case you want
>>>>>>>>> to read up on it. Essentially you're moving the for loop over
>>>>>>>>> each leaf on to
>>>>>>>>> the GPU.
>>>>>>>>>
>>>>>>>>> Typically, you'd have your data for the leaves in an array in C++
>>>>>>>>> and use this
>>>>>>>>> to populate the leaf instance buffer.
>>>>>>>>>
>>>>>>>>> The plan is to have a batcher that uses this instancing facility.
>>>>>>>>>
>>>>>>>>> Cheers,
>>>>>>>>>
>>>>>>>>> Sean
>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> And one more - now you can rotate the tree with the left mouse
>>>>>>>>>> button.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> 11.04.2017 12:15, Igor Mironchik пишет:
>>>>>>>>>>>
>>>>>>>>>>> Hi,
>>>>>>>>>>>
>>>>>>>>>>> I fixed a little 3Dtree. Now branches positions are correct. And I
>>>>>>>>>>> know that not all leafs is visible (this is because leaf
>>>>>>>>>>> geometry is
>>>>>>>>>>> implemented as plain which renders only on one side).
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> 10.04.2017 13:20, Igor Mironchik пишет:
>>>>>>>>>>>>
>>>>>>>>>>>> Hello,
>>>>>>>>>>>>
>>>>>>>>>>>> I guess that Qt3D has huge memory leaks.
>>>>>>>>>>>>
>>>>>>>>>>>> You can check it on this example:
>>>>>>>>>>>> https://github.com/igormironchik/3Dtree
>>>>>>>>>>>>
>>>>>>>>>>>> It's 3D tree, that grows year by year.
>>>>>>>>>>>>
>>>>>>>>>>>> By default tree will grow 5 years (5 minutes).
>>>>>>>>>>>>
>>>>>>>>>>>> When tree grown you can restart tree. And here I delete all
>>>>>>>>>>>> resources:
>>>>>>>>>>>>
>>>>>>>>>>>> void
>>>>>>>>>>>>
>>>>>>>>>>>> MainWindowPrivate::createTree()
>>>>>>>>>>>> {
>>>>>>>>>>>> if(m_tree)
>>>>>>>>>>>> {
>>>>>>>>>>>> for(constauto&e:m_rootEntity->childNodes())
>>>>>>>>>>>> e->deleteLater();
>>>>>>>>>>>> }
>>>>>>>>>>>> m_tree=newBranch(m_startPos,m_endPos,c_startBranchRadius,
>>>>>>>>>>>> true,m_rootEntity);
>>>>>>>>>>>> m_tree->setAge(0.0f);
>>>>>>>>>>>> m_tree->updatePosition();
>>>>>>>>>>>> m_tree->placeLeafs();
>>>>>>>>>>>> }
>>>>>>>>>>>>
>>>>>>>>>>>> But a lot of memory are eaten.
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
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