Microsoft has released Work Graphs technology, which is part of the latest version of DirectX 12. This technology will relieve the CPU by moving task scheduling to the video card, which will theoretically give a performance boost to systems with low-power CPUs.
Now the final image on the screen is formed by the joint efforts of the CPU and GPU, but sometimes the CPU does not have time to prepare tasks for calculation on the GPU, as a result the video card is idle, waiting for new instructions. Work Graphs technology is designed to make the GPU more autonomous so that it can submit work tasks to itself and reduce the number of calls to the CPU.
With Work Graphs, game developers can optimize producer-to-consumer pipelines that efficiently move heavy workloads from the CPU to the GPU. In this system, a thread running on the GPU (producer) can register a request to do other work (consumer). Work will be scheduled by the GPU as soon as there is free space, and this thread can also become a consumer if necessary. Simply put, instead of waiting for each step of the calculation to complete, the CPU can create a sequence of tasks that the GPU will perform without having to contact the CPU each time.
The interaction between the central and graphic processors is expected to be further accelerated thanks to the GPU Upload Heaps function from Shader Model 6.8 – it allows the CPU and GPU to exchange data much faster, due to the absence of the need to transfer data from video memory to the central processor via the PCI bus. This feature uses ResizableBAR technology, which allows the CPU to write data to video memory with minimal delay.
Work Graphs and Shader Model 6.8 are now available to game developers via Agility SDK 1.613. This SDK can already be used with the latest AMD and NVIDIA drivers. Work Graphs is supported on NVIDIA Ampere and Ada Lovelace GPUs (GeForce RTX 3000 and RTX 4000) with driver version 551.76 or later installed. As for AMD, Work Graphs currently only works on GPUs with RDNA3 architecture (Radeon RX 7000 video cards). Updated drivers supporting the new SDK from Intel have not yet been released.
It is worth noting that updating the video driver alone will not improve performance – Work Graphs technology must be implemented in games, which means game developers must also support the initiative.
NVIDIA has also published a technical demo to evaluate Work Graphs. The video above shows its work – at about 1:20 you can see a noticeable increase in productivity due to the new technology. The test used GeForce RTX 4090 video cards and the Ryzen 7 7700X processor.
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