VK_KHR_descriptor_update_template support

[Ankit Navik]

Hi, 

Angle uses DescriptorSet as default, 
I am thinking of VK_KHR_descriptor_update_template support require to be added. which can reduces the CPU overhead. 
what would be involved in implementing and supporting it? 

I understood the current DescriptorSet has caching mechanism which might be already reducing the CPU overhead. Am I right? so I am thinking loud that what would be involved if VK_KHR_descriptor_update_template implemented and how much impact would be? 
 
Also, I've seen a few post on web that VK_EXT_descriptor_buffer can entirely changes/replace DescriptorSet or DescriptorUpdateTemplate. Hence thinking out loud especially ROI. 

Regards, 
Ankit

[Shahbaz Youssefi]

Hi,

I don't think we can really know that without trying. FWIW, we have a tracking issue for this at anglebug.com/42264241, you could use to discuss this in a more centralized way.

VK_KHR_descriptor_update_template is promoted to Vulkan 1.1, which is ANGLE's minimum required version. It's probably not too hard to set it up in ANGLE, and measure the benefits. You are welcome to give that a try.

W.r.t VK_EXT_descriptor_buffer, it's not an extension some mobile vendors can support, but using it in ANGLE could still be beneficial on those that do (and it can get us prepared for some other future stuff coming in Vulkan). Does it need compiler changes too? Either way, my suggestion would be to use descriptor update templates right away, and then look at descriptor buffer.

To answer the ROI question directly, yes I believe both should be beneficial.