Archives Discussions

[ryta1203]

If the TEX and ALU clauses run in parallel and there exists a dependency, is the ALU clause execution halted until the TEX clause is complete? Or just until the dependency is resolved?

It would seem to me that the entire TEX clause would have to complete before allowing the ALU clause to execute, thus if only one dependency exists there might be a long cycle count (assuming a 4 to 1 cycle count and 8 fetches/TEX that would be a 32 cycle latency) before the ALU clause would be allowed to execute because of one dependency?

Is this correct? If so or not, can I find this in the ISA docs and where?

[Jawed]

Yes that's right, the entire texture clause must first finish.

Jawed

[ryta1203]

Originally posted by: Jawed Yes that's right, the entire texture clause must first finish.

Jawed

Can you point me to the doc that states this? Thanks.

[Jawed]

Threading and Texture Latency Hiding

Multi-thread graphic processing system

Method and apparatus for managing tasks in a multiprocessor system  

If there's something friendlier I've forgotten about it.

Jawed

[ryta1203]

Jawed,

  I can only get your first link and that data is pretty old. I'd tend to agree with you though as it appears that is the case and that it makes sense, since switching is clause to clause (though they don't discuss it in detail and don't discuss the differences between fetch units and stream core units operations/switching/execution/etc). This is certainly implied in the docs but it doesn't appear to be explicitly stated.