IDXGIDevice3::Trim method (dxgi1_3.h)

Trims the graphics memory allocated by the IDXGIDevice3 DXGI device on the app's behalf.

For apps that render with DirectX, graphics drivers periodically allocate internal memory buffers in order to speed up subsequent rendering requests. These memory allocations count against the app's memory usage for PLM and in general lead to increased memory usage by the overall system.

Starting in Windows 8.1, apps that render with Direct2D and/or Direct3D (including CoreWindow and XAML interop) must call Trim in response to the PLM suspend callback. The Direct3D runtime and the graphics driver will discard internal memory buffers allocated for the app, reducing its memory footprint.

Calling this method does not change the rendering state of the graphics device and it has no effect on rendering operations. There is a brief performance hit when internal buffers are reallocated during the first rendering operations after the Trim call, therefore apps should only call Trim when going idle for a period of time (in response to PLM suspend, for example).

Apps should ensure that they call Trim as one of the last D3D operations done before going idle. Direct3D will normally defer the destruction of D3D objects. Calling Trim, however, forces Direct3D to destroy objects immediately. For this reason, it is not guaranteed that releasing the final reference on Direct3D objects after calling Trim will cause the object to be destroyed and memory to be deallocated before the app suspends.

Similar to ID3D11DeviceContext::Flush, apps should call ID3D11DeviceContext::ClearState before calling Trim. ClearState clears the Direct3D pipeline bindings, ensuring that Direct3D does not hold any references to the Direct3D objects you are trying to release.

It is also prudent to release references on middleware before calling Trim, as that middleware may also need to release references to Direct3D objects.

Syntax

void Trim();

Return value

None

Requirements

See also

IDXGIDevice3