Mod: This is a thread started in the console space in 2013. A recent new post led to a new conversation. I think it's worth posting here so the AMD experts can explain what their hardware can and can't do. I will copy over some of the arguments from PM.
I know this sound silly but it seems like it's exactly what Sony is planning to do with the 8 ACE's.
It's a few things that I have read over the last year or so that's leading me to believe this is what they are doing I'll try to go back & find all the quotes later but for now I have a question.
If Sony was to config the 64 command queues to make the pipelines emulate real fixed function pipelines could they work just as efficient as real fixed function hardware?
Update June 2016:
PS4 has Hardware Schedulers & they are the reconfigable processors that has been talked about even before the PS4 was revealed , this is the reason why re-projection for VR can be done with little effect on the GPU because they are able to re-config the HWS to run reprojection on the GPU as if it was a processor made for reprojection by controlling how it run on the GPU. Look back at the quotes I put in bold from Cerny in this thread.
For normal code it's fixed function but the functions can be changed by low level microcode that's not something that game devs will be able to do freely it will be done by Sony for adding functions like reprojection & Raytraced audio.
http://www.tomshardware.com/reviews/amd-radeon-rx-480-polaris-10,4616.html
I know this sound silly but it seems like it's exactly what Sony is planning to do with the 8 ACE's.
It's a few things that I have read over the last year or so that's leading me to believe this is what they are doing I'll try to go back & find all the quotes later but for now I have a question.
If Sony was to config the 64 command queues to make the pipelines emulate real fixed function pipelines could they work just as efficient as real fixed function hardware?
Update June 2016:
PS4 has Hardware Schedulers & they are the reconfigable processors that has been talked about even before the PS4 was revealed , this is the reason why re-projection for VR can be done with little effect on the GPU because they are able to re-config the HWS to run reprojection on the GPU as if it was a processor made for reprojection by controlling how it run on the GPU. Look back at the quotes I put in bold from Cerny in this thread.
Those aren't fixed-function pipelines. They are 1) schedulers, not pipelines, with no application in graphics rendering other than organising the rendering pieces. 2) programmable, not fixed-function.
For normal code it's fixed function but the functions can be changed by low level microcode that's not something that game devs will be able to do freely it will be done by Sony for adding functions like reprojection & Raytraced audio.
A single Graphics Command Processor up front is still responsible for dispatching graphics queues to the Shader Engines. So too are the Asynchronous Compute Engines tasked with handling compute queues. Only now AMD says its command processing logic consists of four ACEs instead of eight, with two Hardware Scheduler units in place for prioritized queues, temporal/spatial resource management and offloading CPU kernel mode driver scheduling tasks. These aren’t separate or new blocks per se, but rather an optional mode the existing pipelines can run in. Dave Nalasco, senior technology manager for graphics at AMD, helps clarify their purpose:
"The HWS (Hardware Workgroup/Wavefront Schedulers) are essentially ACE pipelines that are configured without dispatch controllers. Their job is to offload the CPU by handling the scheduling of user/driver queues on the available hardware queue slots. They are microcode-programmable processors that can implement a variety of scheduling policies. We used them to implement the Quick Response Queue and CU Reservation features in Polaris, and we were able to port those changes to third-generation GCN products with driver updates."
Quick Response Queues allow developers to prioritize certain tasks running asynchronously without preempting other processes entirely. In case you missed Dave's blog post on this feature, you cancheck it out here. In short, though, flexibility is the point AMD wants to drive home. Its architecture allows multiple approaches to improving utilization and minimizing latency, both of which are immensely important in applications like VR.
http://www.tomshardware.com/reviews/amd-radeon-rx-480-polaris-10,4616.html
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