Ppsspp: [Discuss] OpenGL and Vulkan Threading

[zminhquanz]

When i use OpenGL with new GL Threading Manager , it's use two thread of CPU , some time performance reach same speed on Vulkan or higher in some scenario

But on Vulkan API , it's low level API and higher perfomance than OpenGL , but it's use almost one thread , on second thread it's using very little

[hrydgard]

It's just faster (much less CPU cost) to generate Vulkan command buffers than it is to issue OpenGL commands. So overall with Vulkan you'll see lower CPU consumption, and especially on NVIDIA drivers, the Vulkan drawing thread will just not have very much to do as it's so cheap to generate vulkan command buffers. On mobile drivers you'll find that it's more "even".

You're right that this means that there could be room for moving over more things to the rendering thread in Vulkan. There are a few, like "descriptor set" management, and that's a possible improvement for the future, but the main thread is mostly busy doing CPU emulation and PSP command buffer interpretation, and those have to stay on the CPU thread.

[fahadfoyjur]

How to enable multi thread , for android ?? Any option ,??

[hrydgard]

@fahadfoyjur It's always enabled. You can't turn it off.

[zminhquanz]

@hrydgard =)) , So , if you doing that correct , Vulkan API using more than 2 thread on OpenGL ( 3-4 core , something like that )

[fahadfoyjur]

You are so hard working for us that this is our biggest achievement
:-)
hrydgard . Thanks

[unknownbrackets]

Going to close, since it was noted this behavior is expected.

If there's specific ideas for moving things to the Vulkan render thread, we should open specific issues (or pull requests) for them.

-[Unknown]