[Development] Proposal for "container-oriented deterministic memory manager"

Phil Bouchard philippeb8 at gmail.com
Sun Dec 25 06:49:48 CET 2016

On 12/25/2016 12:25 AM, Konstantin Tokarev wrote:
>> Greetings,
>> I am a QML developer and it came to my attention that the animation is
>> sluggish because of the internal garbage collector.
> Do you have any proofs that GC is to blame here?

My app works fine below a certain threshold but as soon as I reach a 
certain level of complexity, the animation of the app randomly starts 
skipping frames.  I know the GC randomly kicks in so it fits the same 

>> I know about the
>> QtQuickCompiler that could speed up the rendering but it still uses a
>> garbage collector.
>> I wrote myself a "container-oriented deterministic memory manager"
>> called "root_ptr" that could definitely speed up animation of QML objects:
>> https://github.com/philippeb8/root_ptr
> Any numbers for "definitely speed up"?

Well as you can see on the aforementioned link, root_ptr is as fast as 
the best usage of shared_ptr but detects cycles and uses the same amount 
of memory per pointer.

Furthermore it is "deterministic" so it's not going to randomly slow 
down the animation of your app.  Also it is "container-oriented" meaning 
once the "root_ptr" of a container is deleted, all of its child ptrs 
gets instantly deleted, bringing down all potential cycles.  So the 
deletion of a Javascript page will not leave any dangling memory block 

I have talked previously to the WebKit group but their implementation is 
too complex to simply "swap" the memory manager.  So I was hoping the 
QtQuickCompiler generates a cleaner memory manager that could be swapped 
relatively easily.

>> Is that something that could be easily integrated into the
>> QtQuickCompiler? If so would there be any interests to integrate root_ptr?
>> Sincerely,
>> -Phil
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