Problems on NVIDIA - System

Vulkan
1

Hello guys,
i am programming a rendering engine with vulkan on my desktop pc using a AMD Radeon HD 7870.
Everything works fine on that system, but when i run the application on my laptop (using a gtx 765M), i have a horrible problem(s).
1.) The Application continously allocate memory on the heap and the FPS decreases with time aswell.

I investigated this and actually the “vkQueuePresentKHR()”-function causes this problem.
The Main-Difference between my Laptop and my Desktop is, that my Laptop is using the VK_PRESENT_MODE_MAILBOX (my desktop: immediate) mode.
I tryed the following to fix it:

  • change the amount of Swapchain-Images for the mail-box mode:
    –> Effect: Increasing Swapchain-Images until max-value of 8 decreases fps significantly (8: 5 FPS),
    Memory Leak still appears on VkQueuePresentKHR
  • using VK_PRESENT_MODE_FIFO_KHR and VK_PRESENT_MODE_FIFO_RELAXED_KHR:
    –> My second problem was gone, still “vkQueuePresentKHR” causes the memory leak

So my second problem is (i assume the first error somehow causes this), is that my GUI is sometimes flickering.
I am rendering the GUI with a separate renderpass which loads the same framebuffer attachment and use blending to draw the quads over the scene.
This flickering is gone when using one of the two swapchain-modes or when capping the fps to less than 60.
Interesting effect: When i clear the framebuffer attachment in the GUI-Renderpass (instead of load), the flickering actually causes to make the 3d-szene visible for a moment, which should definitely not happen.

I hope you can help me to figure out whats going on here.

Thanks in Advance
SH

2

do you have some kind of sync between the two renderpasses (pipeline barrier, subpass, dependency from/to external,…)?

3

mh no i havent, i tryed to sync my two command buffers (one for the 3D-szene, the other for the GUI… of course for each swapchain-image) with a semaphore, but things got more worse than before. Flickering all over the place and frame-times increases significantly.
I will reading the spec to synchronisation again and try a little bit soon.

Anyone here have an idea, why “vkQueuePresentKHR” causes the memory leak?

4

You might want to try backing up to driver version 365.19. With versions 368.xx, we’ve seen memory leaks, poor frame rates, and frame rates that decline over time.

5

Weird, today i recognized that the gui-flickering is only present when i build in Visual Studio on x86 but not on x64.

I try another driver and will inform you if that was the reason.

6

Oh cmon, thats sucks ._. works perfectly fine with 365.19…

And i spent hours of debugging xD